Product
Folder
Order
Now
Support &
Community
Tools &
Software
Technical
Documents
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
ADS7138 Small, 8-Channel, 12-Bit ADC With I2C Interface, GPIOs, and CRC
1 Features
2 Applications
•
•
•
•
•
1
•
•
•
•
•
•
•
Small package size:
– 3-mm × 3-mm WQFN
8 channels configurable as any combination of:
– Up to 8 analog inputs, digital inputs, or digital
outputs
GPIOs for I/O expansion:
– Open-drain, push-pull digital outputs
Analog watchdog:
– Programmable thresholds per channel
– Event counter for transient rejection
Wide operating ranges:
– AVDD: 2.35 V to 5.5 V
– DVDD: 1.65 V to 5.5 V
– –40°C to +125°C temperature range
CRC for read/write operations:
– CRC on data read/write
– CRC on power-up configuration
I2C interface:
– Up to 3.4 MHz (high-speed mode)
– 8 configurable I2C addresses
Programmable averaging filters:
– Programmable sample size for averaging
– Averaging with internal conversions
– 16-bit resolution for average output
Automotive center information displays
Mobile robot CPU boards
Rack servers
Intra-DC interconnect (metro)
3 Description
The ADS7138 is an easy-to-use, 8-channel,
multiplexed, 12-bit, successive approximation register
analog-to-digital converter (SAR ADC). The eight
channels can be independently configured as either
analog inputs, digital inputs, or digital outputs. The
device has an internal oscillator for ADC conversion
processes.
The ADS7138 communicates via an I2C-compatible
interface and operates in either autonomous or
single-shot conversion mode. The ADS7138
implements analog watchdog function by eventtriggered interrupts per channel using a digital
window comparator with programmable high and low
thresholds, hysteresis, and an event counter. The
ADS7138 has a built-in cyclic redundancy check
(CRC) for data read/write operations and the powerup configuration.
Device Information(1)
PART NAME
ADS7138
PACKAGE
BODY SIZE (NOM)
WQFN (16)
3.00 mm × 3.00 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
ADS7138 Block Diagram and Applications
Example System Architecture
Device Block Diagram
DECAP
AVDD
VCC
DVDD
AIN0 / GPIO0
AIN1 / GPIO1
ADC
Digital Window
Comparator
AIN3 / GPIO3
AIN5 / GPIO5
AIN6 / GPIO6
AIN7 / GPIO7
MUX
ADDR
Sequencer
2
I C Interface
GPO Write
GPI Read
ADC
GPIO
MUX
Pin CFG
OVP
ALERT
Programmable
Averaging Filter
AIN2 / GPIO2
AIN4 / GPIO4
LOAD
AVDD
High/Low Threshold
± Hysteresis
OCP
SDA
SCL
CRC
GND
OVP: Over voltage protection
OCP: Over current protection
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Table of Contents
1
2
3
4
5
6
7
8
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Device Comparison Table.....................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
4
5
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
7.9
7.10
5
5
5
5
6
7
7
7
8
9
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
I2C Timing Requirements..........................................
Timing Requirements ................................................
I2C Switching Characteristics....................................
Switching Characteristics ..........................................
Typical Characteristics ............................................
Detailed Description ............................................ 13
8.1 Overview ................................................................. 13
8.2 Functional Block Diagram ....................................... 13
8.3
8.4
8.5
8.6
9
Feature Description.................................................
Device Functional Modes........................................
Programming...........................................................
ADS7138 Registers.................................................
14
22
26
29
Application and Implementation ........................ 69
9.1 Application Information............................................ 69
9.2 Typical Applications ................................................ 69
10 Power Supply Recommendations ..................... 72
10.1 AVDD and DVDD Supply Recommendations....... 72
11 Layout................................................................... 73
11.1 Layout Guidelines ................................................. 73
11.2 Layout Example .................................................... 73
12 Device and Documentation Support ................. 74
12.1
12.2
12.3
12.4
12.5
Receiving Notification of Documentation Updates
Support Resources ...............................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
74
74
74
74
74
13 Mechanical, Packaging, and Orderable
Information ........................................................... 74
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Original (May 2019) to Revision A
•
2
Page
Changed document status from advance information to production data.............................................................................. 1
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
5 Device Comparison Table
PART NUMBER
DESCRIPTION
ADS7128
ADS7138
8-channel, 12-bit ADC with
I2C interface and GPIOs
ADS7138-Q1
CRC MODULE
ZERO-CROSSING-DETECT
(ZCD) MODULE
ROOT-MEAN-SQUARE
(RMS) MODULE
Yes
Yes
Yes
Yes
No
No
Yes
No
No
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
3
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
6 Pin Configuration and Functions
AIN2/GPIO2
1
AIN3/GPIO3
2
AIN1/GPIO1
AIN0/GPIO0
SDA
SCL
16
15
14
13
RTE Package
16-Pin WQFN
Top View
12
ALERT
11
ADDR
10
DVDD
Thermal
7
8
AVDD
DECAP
9
6
4
AIN7/GPIO7
AIN5/GPIO5
Pad
5
3
AIN6/GPIO6
AIN4/GPIO4
GND
Not to scale
Pin Functions
PIN
NAME
NO.
FUNCTION (1)
DESCRIPTION
AIN0/GPIO0
15
AI, DI, DO
Channel 0; configurable as either an analog input (default) or a general-purpose
input/output (GPIO)
AIN1/GPIO1
16
AI, DI, DO
Channel 1; configurable as either an analog input (default) or a GPIO
AIN2/GPIO2
1
AI, DI, DO
Channel 2; configurable as either an analog input (default) or a GPIO
AIN3/GPIO3
2
AI, DI, DO
Channel 3; configurable as either an analog input (default) or a GPIO
AIN4/GPIO4
3
AI, DI, DO
Channel 4; configurable as either an analog input (default) or a GPIO
AIN5/GPIO5
4
AI, DI, DO
Channel 5; configurable as either an analog input (default) or a GPIO
AIN6/GPIO6
5
AI, DI, DO
Channel 6; configurable as either an analog input (default) or a GPIO
AIN7/GPIO7
6
AI, DI, DO
Channel 7; configurable as either an analog input (default) or a GPIO
ADDR
11
AI
ALERT
12
Digital output
AVDD
7
Supply
Analog supply input, also used as the reference voltage to the ADC; connect a
1-µF decoupling capacitor to GND
DECAP
8
Supply
Connect a1-µF decoupling capacitor between the DECAP and GND pins for the
internal power supply
DVDD
10
Supply
Digital I/O supply voltage; connect a 1-µF decoupling capacitor to GND
GND
9
Supply
Ground for the power supply; all analog and digital signals are referred to this
pin voltage
SDA
14
DI, DO
Serial data input or output for the I2C interface
SCL
13
DI
Thermal pad
—
Supply
(1)
4
Input for selecting the device I2C address.
Connect a resistor to this pin from DECAP pin or GND to select one of the eight
addresses.
Open-drain (default) or push-pull output for the digital comparator
Serial clock for the I2C interface
Exposed thermal pad; connect to GND.
AI = analog input, DI = digital input, and DO = digital output.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
7 Specifications
7.1 Absolute Maximum Ratings
over operating ambient temperature range (unless otherwise noted) (1)
DVDD to GND
AVDD to GND
MIN
MAX
–0.3
5.5
UNIT
V
–0.3
5.5
V
AINx/GPOx (2)
GND – 0.3 AVDD + 0.3
V
ADDR
GND – 0.3
2.1
V
Digital inputs
GND – 0.3
5.5
V
Current through any pin except supply pins (3)
–10
10
mA
Junction temperature, TJ
–40
125
°C
Storage temperature, Tstg
–60
150
°C
(1)
(2)
(3)
Stresses beyond those listed under Absolute Maximum Rating may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Condition. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
AINx/GPIOx refers to pins 1, 2, 3, 4, 5, 6, 15, and 16.
Pin current must be limited to 10mA or less.
7.2 ESD Ratings
VALUE
V(ESD)
(1)
(2)
Electrostatic discharge
Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins (1)
±2000
Charged device model (CDM), per JEDEC specification JESD22-C101, all
pins (2)
±500
UNIT
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
7.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
POWER SUPPLY
AVDD
Analog supply voltage
2.35
3.3
5.5
V
DVDD
Digital supply voltage
1.65
3.3
5.5
V
0
AVDD
V
–0.1
AVDD + 0.1
V
125
℃
ANALOG INPUTS
FSR
Full-scale input range
AINX (1) - GND
VIN
Absolute input voltage
AINX - GND
TEMPERATURE RANGE
TA
(1)
Ambient temperature
–40
25
AINx refers to AIN0, AIN1, AIN2, AIN3, AIN4, AIN5, AIN6, and AIN7.
7.4 Thermal Information
ADS7138
THERMAL METRIC
(1)
RTE (WQFN)
UNIT
16 PINS
RθJA
Junction-to-ambient thermal resistance
49.7
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
53.4
°C/W
RθJB
Junction-to-board thermal resistance
24.7
°C/W
ΨJT
Junction-to-top characterization parameter
1.3
°C/W
ΨJB
Junction-to-board characterization parameter
24.7
°C/W
RθJC(bot)
Junction-to-case (bottom) thermal resistance
9.3
°C/W
(1)
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
5
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
7.5 Electrical Characteristics
at AVDD = 2.35 V to 5 V, DVDD = 1.65 V to 5.5 V, and maximum throughput (unless otherwise noted); minimum and
maximum values at TA = –40°C to +125°C; typical values at TA = 25°C.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
ANALOG INPUTS
CSH
Sampling capacitance
12
pF
DC PERFORMANCE
Resolution
No missing codes
DNL
Differential nonlinearity
INL
Integral nonlinearity
V(OS)
Input offset error
Post offset calibration
Input offset thermal drift
Post offset calibration
GE
Gain error
12
bits
–0.75
±0.45
0.75
LSB
–1.5
±0.5
1.5
LSB
–2
±0.3
2
±1
–0.065
Gain error thermal drift
±0.05
LSB
ppm/°C
0.65
±1
%FSR
ppm/°C
AC PERFORMANCE
AVDD = 5 V, fIN = 2 kHz
70
72.8
AVDD = 3 V, fIN = 2 kHz
69.8
72.4
AVDD = 5 V, fIN = 2 kHz
71.2
73
AVDD = 3 V, fIN = 2 kHz
70.5
72.5
SINAD
Signal-to-noise + distortion ratio
dB
SNR
Signal-to-noise ratio
THD
Total harmonic distortion
fIN = 2 kHz
–85
dB
SFDR
Spurious-free dynamic range
fIN = 2 kHz
91
dB
Crosstalk
100-kHz signal applied on any OFF
channel and measured on ON the
channel
–100
dB
dB
DECAP Pin
CDECAP
Decoupling capacitor on DECAP
pin
Voltage output on DECAP pin
0.1
CDECAP = 1 µF
1
4.7
1.8
µF
V
DIGITAL INPUT/OUTPUT (SCL, SDA)
VIH
Input high logic level
All I2C modes
0.7 x DVDD
DVDD
V
VIL
Input low logic level
All I2C modes
–0.3
0.3 x DVDD
V
Sink current = 2 mA, DVDD > 2 V
0
0.4
Sink current = 2 mA, DVDD ≤ 2 V
0
0.2 x DVDD
VOL
IOL
Output low logic level
Low-level output current (sink)
VOL = 0.4 V, standard and fast
Mode
3
VOL = 0.6 V, fast mode
6
VOL = 0.4 V, fast mode plus
V
mA
20
GPIOs
VIH
Input high logic level
VIL
Input low logic level
0.7 x AVDD
AVDD + 0.3
–0.3
V
0.3 x AVDD
V
100
nA
0.8 x AVDD
AVDD
V
0
0.2 x AVDD
Input leakge current
GPIO configured as input
10
VOH
Output high logic level
GPO_DRIVE_CFG = push-pull,
ISOURCE = 2 mA
VOL
Output low logic level
ISINK = 2 mA
IOH
Output high source current
VOH > 0.7 x AVDD
5
mA
IOL
Output low sink current
VOL < 0.3 x AVDD
5
mA
V
DIGITAL OUTPUT (ALERT)
VOH
Output high logic level
GPO_DRIVE_CFG = push-pull,
ISOURCE = 2 mA
VOL
Output low logic level
ISINK = 2 mA
IOH
Output high sink current
VOH > 0.7 x DVDD
6
Submit Documentation Feedback
0.8 x DVDD
DVDD
V
0
0.2 x DVDD
V
5
mA
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Electrical Characteristics (continued)
at AVDD = 2.35 V to 5 V, DVDD = 1.65 V to 5.5 V, and maximum throughput (unless otherwise noted); minimum and
maximum values at TA = –40°C to +125°C; typical values at TA = 25°C.
PARAMETER
IOL
TEST CONDITIONS
Output low sink current
MIN
TYP
MAX
VOL < 0.3 x DVDD
UNIT
5
mA
POWER SUPPLY CURRENTS
I2C high-speed mode, AVDD = 5 V
150
210
45
85
I C fast mode, AVDD = 5 V
28
46
I2C standard mode, AVDD = 5 V
12
26
7
20
I2C fast mode plus, AVDD = 5 V
IAVDD
2
Analog supply current
No conversion, AVDD = 5 V
µA
7.6 I2C Timing Requirements
MODE (1)
STANDARD, FAST, AND
FAST MODE PLUS
MIN
MAX
(2)
HIGH-SPEED MODE
MIN
UNIT
MAX
fSCL
SCL clock frequency
tSUSTA
START condition setup time for repeated start
260
160
ns
tHDSTA
Start condition hold time
260
160
ns
tLOW
Clock low period
500
160
ns
tHIGH
Clock high period
260
60
ns
tSUDAT
Data in setup time
50
10
ns
tHDDAT
Data in hold time
0
0
ns
tR
SCL rise time
120
80
ns
tF
SCL fall time
120
80
ns
tSUSTO
STOP condition hold time
260
60
ns
tBUF
Bus free time before new transmission
500
300
ns
(1)
(2)
1
3.4
MHz
The device supports standard, full-speed, and fast modes by default on power-up. For selecting high-speed mode refer to the section on
Configuring the Device for High-Speed I2C Mode.
Bus load (CB) consideration; CB ≤ 400 pF for fSCL ≤ 1 MHz; CB < 100 pF for fSCL = 3.4 MHz.
7.7 Timing Requirements
at AVDD = 2.35 V to 5 V, DVDD = 1.65 V to 5.5 V, and maximum throughput (unless otherwise noted); minimum and
maximum values at TA = –40°C to +125°C; typical values at TA = 25°C.
MIN
tACQ
Acquisition time
MAX
UNIT
300
ns
7.8 I2C Switching Characteristics
MODE
STANDARD, FAST, AND
FAST MODE PLUS
MIN
tVDDATA
SCL low to SDA data out valid
tVDACK
SCL low to SDA acknowledge time
tSTRETCH
Clock stretch time in one-shot conversion mode
tSP
Noise supression time constant on SDA and SCL
MAX
450
HIGH-SPEED MODE
MIN
UNIT
MAX
200
ns
450
200
ns
1400
1000
ns
50
10
ns
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
7
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
7.9 Switching Characteristics
at AVDD = 2.35 V to 5 V, DVDD = 1.65 V to 5.5 V, and maximum throughput (unless otherwise noted); minimum and
maximum values at TA = –40°C to +125°C; typical values at TA = 25°C.
PARAMETER
TEST CONDITIONS
MIN
MAX
UNIT
CONVERSION CYCLE
tCONV
Manual and auto
sequence modes
ADC conversion time
Autonomous mode
tSTRETCH
ns
600
ns
5
ms
5
ms
RESET AND ALERT
AVDD ≥ 2.35 V
tPU
Power-up time for device
tRST
Delay time; RST bit = 1b to device reset
complete (1)
tALERT_HI
ALERT high period
ALERT_LOGIC[1:0]
= 1x
50
150
ns
tALERT_LO
ALERT low period
ALERT_LOGIC[1:0]
= 1x
50
150
ns
(1)
RST bit is automatically reset to 0b after tRST.
9th clock
tLOW
tHIGH
SCL
tR
tSUDAT
tF
tSUSTO
tSTRETCH
tHDSTA tHDDAT
tSUSTA
tSP
SDA
tBUF
P
tVDDAT
tVDACK
Sr
S
P
NOTE: S = start, Sr = repeated start, and P = stop.
Figure 1. I2C Timing Diagram
8
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
7.10 Typical Characteristics
at TA = 25°C, AVDD = 5 V, DVDD = 3.3 V, and maximum throughput (unless otherwise noted)
Frequency
45000
0.8
Differential Nonlinearity (LSB)
60000
39581
30000
25955
15000
0.4
0
-0.4
-0.8
0
2048
2049
0
Output Code
1024
2048
Output Code
C001
Standard deviation = 0.49 LSB
3072
4095
C002
Typical DNL = ±0.2 LSB
Figure 2. DC Input Histogram
Figure 3. Typical DNL
0.8
0.5
0.3
0.4
Differential Nonlinearity
Integral Nonlinearity (LSB)
Minimum
Maximum
0
-0.4
0.1
-0.1
-0.3
-0.8
0
1024
2048
Output Code
3072
-0.5
-40
4095
-7
C004
26
59
Temperature (°C)
92
125
C003
Typical INL = ±0.5 LSB
Figure 4. Typical INL
Figure 5. DNL vs Temperature
0.75
Differential Nonlinearity (LSB)
Integral Nonlinearity (LSB)
0.6
0.3
Minimum
Maximum
0
-0.3
-0.6
-40
-7
26
59
Temperature (°C)
92
125
0.5
Maximum
Minimum
0.25
0
-0.25
-0.5
-0.75
2.5
C005
3
3.5
4
AVDD (V)
4.5
5
5.5
C018
Figure 7. DNL vs AVDD
Figure 6. INL vs Temperature
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
9
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Typical Characteristics (continued)
at TA = 25°C, AVDD = 5 V, DVDD = 3.3 V, and maximum throughput (unless otherwise noted)
0.5
0.5
Maximum
Minimum
0.3
Offset Error (LSB)
Integral Nonlinearity (LSB)
0.75
0.25
0
-0.25
-0.5
-0.75
2.5
0.1
-0.1
-0.3
3
3.5
4
AVDD (V)
4.5
5
-0.5
-40
5.5
C019
-7
26
59
Temperature (°C)
92
125
C006
Figure 8. INL vs AVDD
0.5
0.45
0.3
Offset error (LSB)
Gain Error (%FSR)
Figure 9. Offset Error vs Temperature
0.75
0.15
-0.15
0.1
-0.1
-0.3
-0.45
-0.75
-40
-7
26
59
Temperature (°C)
92
-0.5
2.5
125
3
4.5
5
5.5
C016
Figure 11. Offset Error vs AVDD
1
0
0.6
-30
Amplitude (dBFS)
Gain error (%FSR)
4
AVDD (V)
C007
Figure 10. Gain Error vs Temperature
0.2
-0.2
-0.6
-1
2.5
3.5
-60
-90
-120
-150
3
3.5
4
AVDD (V)
4.5
5
5.5
0
16.7
C017
33.4
50.1
Frequency (kHz)
66.8
83.5
C008
fIN = 2 kHz, SNR = 73.2 dB, THD = 92.3 dB
Figure 12. Gain Error vs AVDD
10
Figure 13. Typical FFT
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Typical Characteristics (continued)
at TA = 25°C, AVDD = 5 V, DVDD = 3.3 V, and maximum throughput (unless otherwise noted)
73.5
73.2
11.8
73
11.775
72.8
-40
-7
26
59
Temperature (°C)
SNR, SINAD (dBFS)
11.825
ENOB (Bits)
SNR, SINAD (dBFS)
73.2
73.4
11.75
125
92
12
SINAD
SNR
ENOB
72.9
11.8
72.6
11.7
72.3
11.6
72
2.5
3
Figure 14. Noise Performance vs Temperature
96
-90
94.5
-91
93
91.5
125
THD (dBFS)
-89
SFDR (dBFS)
THD (dBFS)
97.5
C010
94
-84
92
-86
90
-88
88
-90
2.5
3
3.5
4
AVDD (V)
C011
Figure 16. Distortion Performance vs Temperature
132
140
129
135
126
130
125
4.5
86
5.5
5
C012
Figure 17. Distortion Performance vs AVDD
145
IAVDD (PA)
IAVDD (PA)
11.5
5.5
5
THD
SFDR
-88
92
4.5
Figure 15. Noise Performance vs AVDD
THD
SFDR
26
59
Temperature (°C)
4
AVDD (V)
-82
99
-7
3.5
C009
-87
-92
-40
11.9
ENOB (Bits)
11.85
SINAD
SNR
ENOB
SFDR (dBFS)
73.6
123
120
120
-40
-7
26
59
Temperature (°C)
92
125
117
2.5
3
C013
Figure 18. Analog Supply Current vs Temperature
3.5
4
AVDD (V)
4.5
5
5.5
C014
Figure 19. Analog Supply Current vs AVDD
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
11
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Typical Characteristics (continued)
at TA = 25°C, AVDD = 5 V, DVDD = 3.3 V, and maximum throughput (unless otherwise noted)
150
IAVDD (µA)
120
90
60
30
0
0
30
60
90
120
Throughput (kSPS)
150
180
C015
Figure 20. Analog Supply Current vs Throughput
12
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
8 Detailed Description
8.1 Overview
The ADS7138 is a small, eight-channel, multiplexed, 12-bit, analog-to-digital converter (ADC) with an I2Ccompatible serial interface. The eight channels of the ADS7138 can be individually configured as either analog
inputs, digital inputs, or digital outputs. The device includes a digital comparator with a dedicated alert pin that
can be used to interrupt the host when a programmed high or low threshold is crossed on any input channel. The
device uses an internal oscillator for conversion. The ADC can be used in the manual mode for reading ADC
data over the I2C interface or in autonomous mode for monitoring the analog inputs without an active I2C
interface.
The device features a programmable averaging filter that outputs a 16-bit result for enhanced resolution.
The I2C serial interface supports standard-mode, fast-mode, fast-mode plus, and high-speed mode. The device
also features an 8-bit cyclic redundancy check (CRC) for the serial communication interface.
8.2 Functional Block Diagram
DECAP
AVDD
High/Low Threshold
± Hysteresis
DVDD
AIN0 / GPIO0
AIN1 / GPIO1
ADC
ALERT
Programmable
Averaging Filter
AIN2 / GPIO2
Digital Window
Comparator
AIN3 / GPIO3
AIN4 / GPIO4
MUX
AIN5 / GPIO5
AIN6 / GPIO6
AIN7 / GPIO7
ADDR
Sequencer
Pin CFG
2
I C Interface
GPO Write
GPI Read
SDA
SCL
CRC
GND
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
13
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
8.3 Feature Description
8.3.1 Multiplexer and ADC
The eight channels of the multiplexer can be independently configured as ADC inputs or general-purpose
inputs/outputs (GPIOs). Figure 21 shows that each input pin has electrostatic discharge (ESD) protection diodes
to AVDD and GND. On power-up or after device reset, all eight multiplexer channels are configured as analog
inputs.
Figure 21 shows an equivalent circuit for pins configured as analog inputs. The ADC sampling switch is
represented by an ideal switch (SW) in series with the resistor, RSW (typically 150 Ω), and the sampling capacitor,
CSH (typically 12 pF).
GPO_VALUE[0]
GPIO_CFG[0]
AVDD
GPI_VALUE[0]
PIN_CFG[0]
AIN0 / GPIO0
RSW
SW
MUX
Multiplexer
AVDD
CSH
ADC
AIN7 / GPIO7
PIN_CFG[7]
GPI_VALUE[7]
GPIO_CFG[7]
GPO_VALUE[7]
Figure 21. Analog Inputs, GPIOs, and ADC Connections
During acquisition, the SW switch is closed to allow the signal on the selected analog input channel to charge the
internal sampling capacitor. During conversion, the SW switch is opened to disconnect the analog input channel
from the sampling capacitor.
The multiplexer channels can be configured as GPIOs in the PIN_CFG register. The direction of a GPIO (either
as an input or an output) can be set in the GPIO_CFG register. The logic level on the channels configured as
digital I/O can be read from the GPI_VALUE register. The digital outputs can be accessed by writing to the
GPO_VALUE register. The digital outputs can be configured as either open-drain or push-pull in the
GPO_DRIVE_CFG register.
8.3.2 Reference
The device uses the analog supply voltage (AVDD) as a reference for the analog-to-digital conversion process.
TI recommends connecting a 1-µF, low-equivalent series resistance (ESR) ceramic decoupling capacitor
between the AVDD and GND pins.
8.3.3 ADC Transfer Function
The ADC output is in straight binary format. Equation 1 computes the ADC resolution:
1 LSB = VREF / 2N
where:
•
•
VREF = AVDD
N = 12
(1)
Figure 22 and Table 1 detail the transfer characteristics for the device.
14
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Feature Description (continued)
ADC Code (Hex)
PFSC
MC + 1
MC
NFSC+1
NFSC
VIN
1 LSB
AVDD/2 (AVDD/2 + 1 LSB)
(AVDD ± 1 LSB)
Figure 22. Ideal Transfer Characteristics
Table 1. Transfer Characteristics
INPUT VOLTAGE
CODE
DESCRIPTION
IDEAL OUTPUT CODE
≤1 LSB
NFSC
Negative full-scale code
000
1 LSB to 2 LSBs
NFSC + 1
—
001
(AVDD / 2) to (AVDD / 2) + 1 LSB
MC
Mid code
800
(AVDD / 2) + 1 LSB to (AVDD / 2) + 2 LSB
MC + 1
—
801
≥ AVDD – 1 LSB
PFSC
Positive full-scale code
FFF
8.3.4 ADC Offset Calibration
The variation in ADC offset error resulting from changes in temperature or AVDD can be calibrated by setting the
CAL bit in the GENERAL_CFG register. The CAL bit is reset to 0 after calibration. The host can poll the CAL bit
to check the ADC offset calibration completion status.
8.3.5 I2C Address Selector
The I2C address for the device is determined by connecting external resistors on the ADDR pin. The device
address is determined at power-up based on the resistor values. The device retains this address until the next
power-up event, until the next device reset, or until the device receives a command to program its own address.
Figure 23 shows a connection diagram for the ADDR pin and Table 2 lists the resistor values for selecting
different addresses of the device.
DECAP Pin
R1
ADDR
R2
Figure 23. External Resistor Connection Diagram for the ADDR Pin
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
15
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Table 2. I2C Address Selection
RESISTORS
R2 (1)
0Ω
DNP (2)
001 0111b (17h)
11 kΩ
DNP (2)
001 0110b (16h)
33 kΩ
DNP (2)
001 0101b (15h)
100 kΩ
DNP (2)
001 0100b (14h)
(2)
(2)
001 0000b (10h)
DNP
DNP
DNP (2)
11 kΩ
001 0001b (11h)
DNP (2)
33 kΩ
001 0010b (12h)
100 kΩ
001 0011b (13h)
DNP
(1)
(2)
ADDRESS
R1 (1)
(2)
Tolerance for R1, R2 ≤ ±5%.
DNP = Do not populate.
8.3.6 Programmable Averaging Filter
The ADS7138 features a built-in oversampling (OSR) function that can be used to average several samples. The
averaging filter can be enabled by programming the OSR[2:0] bits in the OSR_CFG register. The averaging filter
configuration is common to all analog input channels. Figure 24 shows that the averaging filter module output is
16 bits long. In the manual conversion mode and auto-sequence mode, only the first conversion for the selected
analog input channel must be initiated by the host; see the Manual Mode and Auto-Sequence Mode sections. As
shown in Figure 24, any remaining conversions for the selected averaging factor are generated internally. The
time required to complete the averaging operation is determined by the sampling speed and number of samples
to be averaged. As shown in Figure 24, the 16-bit result can be read out after the averaging operation completes.
Sample AINX
S
7-bit ADDR
R
Sample AINX
A
Sample AINX
Sample AINX
OSR_DONE = 1
Bus idle or Poll OSR_DONE bit
DATA[15:8]
A
DATA[7:0]
A
OSR_DONE = 0
OSR_CFG[2:0] = 2
Time = tCONV x OSR_CFG[2:0]
Data from host to device
Data from device to host
Figure 24. Averaging Example
In Figure 24, SCL is stretched by the device after the start of conversions until the averaging operation is
complete.
If SCL stretching is not required during averaging, enable the statistics registers by setting STATS_EN to 1b and
initiate conversions by writing 1b to the CNVST bit. The OSR_DONE bit in the SYSTEM_STATUS register can
be polled to check the averaging completion status. When using the CNVST bit to initiate conversion, the result
can be read in the RECENT_CHx_LSB and RECENT_CHx_MSB registers.
In the autonomous mode of operation, samples from the analog input channels that are enabled in the
AUTO_SEQ_CH_SEL register are averaged sequentially; see the Autonomous Mode section. The digital window
comparator compares the top 12 bits of the 16-bit average result with the thresholds.
Equation 2 provides the LSB value of the 16-bit average result.
AVDD
1 LSB
216
16
Submit Documentation Feedback
(2)
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
8.3.7 CRC on Data Interface
The ADS7138 features a cyclic redundancy check (CRC) module for checking the integrity of the data bits
exchanged over the I2C interface. The CRC module is bidirectional and appends an 8-bit CRC to every byte read
from the device while also evaluating the CRC of every incoming byte over the I2C interface. The CRC module
uses the CRC-8-CCITT polynomial (x8 + x2 + x + 1) for CRC computation.
To enable the CRC module, set the CRC_EN bit in the GENERAL_CFG register. Table 3 shows how a CRC
error can be detected when configuring the ADS7138.
Table 3. Configuration Notifications When a CRC Error is Detected
CRC ERROR NOTIFICATION
CONFIGURATION
DESCRIPTION
ALERT pin
ALERT_CRCIN = 1b
ALERT pin is asserted if a CRC error is detected by the device.
Status flags
APPEND_STATUS = 10b
4-bit status flags are appended to the ADC data; see the Output Data
Format section for details.
Register read
—
Read the CRC_ERR_IN bit to check if a CRC error is detected.
When the ADS7138 detects a CRC error, the erroneous data are ignored and the CRC_ERR_IN bit is set.
Table 3 describes the additional notifications that can be enabled. Further register writes are disabled until the
CRC_ERR_IN bit is cleared by writing 1b to it. When using autonomous mode, further conversions can be
disabled on the CRC error by setting CONV_ON_ERR to 1b; see the Autonomous Mode section.
8.3.8 General-Purpose I/Os (GPIOs)
The eight channels of the ADS7138 can be independently configured as analog inputs, digital inputs, or digital
outputs. Table 4 describes how the PIN_CFG and GPIO_CFG registers can be used to configure the channels.
Table 4. Configuring Channels as Analog Inputs or GPIOs
PIN_CFG[7:0]
GPIO_CFG[7:0]
GPO_DRIVE_CFG[7:0]
CHANNEL CONFIGURATION
0
x
x
Analog input (default)
1
0
x
Digital input
1
1
0
Digital output; open-drain driver
1
1
1
Digital output; push-pull driver
The digital outputs can be configured to logic 1 or 0 by writing to the GPO_VALUE register. Reading the
GPI_VALUE register returns the logic level for all channels configured as digital inputs.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
17
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
8.3.9 Oscillator and Timing Control
The device uses an internal oscillator for conversions. When using the averaging module, the host initiates the
first conversion and all subsequent conversions are generated internally by the device. Table 5 shows that when
the device generates the start of the conversion, the sampling rate is controlled by the OSC_SEL and
CLK_DIV[3:0] register fields.
Table 5. Configuring Sampling Rate for Internal Conversion Start Control
OSC_SEL = 0
CLK_DIV[3:0]
SAMPLING FREQUENCY,
fCYCLE (kSPS)
OSC_SEL = 1
CYCLE TIME,
tCYCLE (µs)
SAMPLING FREQUENCY, fCYCLE
(kSPS)
CYCLE TIME, tCYCLE
(µs)
0000b
1000
1
31.25
32
0001b
666.7
1.5
20.83
48
0010b
500
2
15.63
64
0011b
333.3
3
10.42
96
0100b
250
4
7.81
128
0101b
166.7
6
5.21
192
0110b
125
8
3.91
256
0111b
83
12
2.60
384
1000b
62.5
16
1.95
512
1001b
41.7
24
1.3
768
1010b
31.3
32
0.98
1024
1011b
20.8
48
0.65
1536
1100b
15.6
64
0.49
2048
1101b
10.4
96
0.33
3072
1110b
7.8
128
0.24
4096
1111b
5.2
192
0.16
6144
The conversion time of the device (see tCONV in the Switching Characteristics table) is independent of the
OSC_SEL and CLK_DIV[3:0] configuration.
8.3.10 Output Data Format
Figure 25 illustrates various I2C frames for reading data.
• Read the ADC conversion result: Two 8-bit I2C packets are required (frame A).
• Read the averaged conversion result: Two 8-bit I2C packets are required (frame B).
• Read data with the channel ID or status flags appended: The 4-bit channel ID or status flags can be
appended to the 12-bit ADC result by configuring the APPEND_STATUS field in the GENERAL_CFG
register. The status flags can be used to detect if a CRC error is detected and if an alert condition is detected
by the digital window comparator. When the channel ID or status flags are appended to the 12-bit ADC data,
two I2C packets are required (frame C). If the channel ID or status flags are appended to the 16-bit average
result, three I2C frames are required (frame D).
18
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Sample A
S
7-bit Slave Address
R
A
Sample A + 1
D11
D10
D9
D8
D7
D6
D5
D4
A
D3
D2
D1
D0
0
0
0
0
A
D7
D6
D5
D4
D3
D2
D1
D0
A
D1
D0
Frame A : Reading ADC data
S
7-bit Slave Address
R
A
D15
D14
D13
D12
D11
D10
D9
D8
A
Frame B : Reading ADC data with averaging enabled
S
7-bit Slave Address
R
A
D11
D10
D9
D8
D7
D6
D5
D4
A
D3
D2
4-bit Channel ID
or Status Flags
A
Frame C : Reading ADC data with status flags or channel ID appended
S
7-bit Slave Address
R
A
D15
D14
D8
A
D7
D6
D0
A
4-bit Channel ID
or Status Flags
0
0
0
0
A
Frame D : Reading ADC data with averaging enabled &
status flags or channel ID appended
Clock stretching for conversion time
Data from host to device
Data from device to host
Figure 25. Data Frames for Reading Data
When status flags are enabled, APPEND_STATUS is set to 10b and four bits are appended to the ADC output.
The device outputs status flags in this order: {1b, 0b, CRCERR_IN, ALERT}. The level transitions on the digital
interface, resulting from the fixed 1b and 0b in the status flags, can be used to detect if the digital outputs are
shorted to a fixed voltage in the system. The CRCERR_IN flag reflects the corresponding bit in the
GENERAL_CFG register. The ALERT flag is the output of the logical OR of the bits in the EVENT_FLAG
register.
8.3.11 Digital Window Comparator
The internal digital window comparator (DWC) is available in all functional modes of the device (see the Device
Functional Modes section for details). The digital window comparator controls output of the ALERT pin buffer.
The ALERT pin can be configured as open-drain (default) or push-pull output using the ALERT_DRIVE bit in the
ALERT_PIN_CFG register. Figure 26 shows a block diagram for the digital window comparator.
EVENT_RGN[7]
EVENT_RGN[0]
Digital input CH0
12-bit ADC data
or
[15:4] Average result
ADC
High threshold Hysteresis
Programmable
Averaging Filter
Event
Counter
Low threshold +
Hysteresis
ALERT
EVENT_HIGH_FLAG[0]
MUX
EVENT_LOW_FLAG[0]
ALERT_CH_SEL[0]
PIN_CFG[0]
GPIO_CFG[0]
All registers are specific for individual
analog input channels
Figure 26. Digital Window Comparator Block Diagram
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
19
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
The low-side threshold, high-side threshold, event counter, and hysteresis parameters are independently
programmable for each input channel. Figure 27 shows the events that can be monitored for every analog input
channel by the window comparator.
High threshold Hysteresis
0xFFF
High threshold Hysteresis
Digital code
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
Signal above limit
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
Digital code
0xFFF
Low threshold +
Hysteresis
0x000
0x000
Low threshold +
Hysteresis
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
Signal below limit
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
Samples
0x000
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
Signal out of band
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
High threshold Hysteresis
DWC_CH_POL = 0
Low threshold +
Hysteresis
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
Signal out of band
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
0xFFF
High threshold Digital code
Digital code
0xFFF
Samples
Hysteresis
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
Signal in band
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxx
Low threshold +
Hysteresis
DWC_CH_POL = 1
0x000
Samples
Samples
Figure 27. Event Monitoring With the Window Comparator
To enable the digital window comparator, set the DWC_EN bit in the GENERAL_CFG register. By default,
hysteresis is 0, the high threshold is 0xFFF, and the low threshold is 0x000. A 12-bit straight binary code cannot
be higher than 0xFFF or lower than 0x000, thus the thresholds have no effect unless set to different values.
Figure 27 shows the various types of event that can be detected by adjusting the thresholds. For detecting when
a signal is in-band, the EVENT_RGN register must be configured. In each of the cases shown in Figure 27,
either or both EVENT_HIGH_FLAG and EVENT_LOW_FLAG can be set.
The programmable event counter counts consecutive thresholds violations before alert flags can be set. The
event count can be set to a higher value to avoid transients in the input signal setting the alert flags.
In order to assert the ALERT pin when the alert flag is set for a particular analog input channel, set the
corresponding bit in the ALERT_CH_SEL register. Alert flags are set regardless of the ALERT_CH_SEL
configuration if DWC_EN is 1 and the high or low thresholds are exceeded.
20
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
8.3.11.1 Interrupts From Digital Inputs
Logic 1 or logic 0 events can detected on channels configured as digital inputs, as shown in Table 6, by enabling
the corresponding ALERT_CH_SEL bit.
Table 6. Configuring Interrupts From Digital Inputs
ALERT_CH_SEL[7:
EVENT_RGN [7:0]
0]
PIN_CFG[7:0]
GPIO_CFG[7:0]
EVENT DESCRIPTION
1
0
1
0
EVENT_HIGH_FLAG is set when digital input channel is at
logic 1.
1
0
1
1
EVENT_LOW_FLAG is set when digital input channel is at
logic 0.
8.3.11.2 Changing Digital Outputs on Alert
Figure 28 shows how digital outputs can be updated in response to alerts from individual channels.
Digital output 7
Digital output 0
Select alerts on which channels
should be enabled as triggers
GPO0_TRIG_EVENT_SEL[7:0]
trigger
GPO_TRIGGER_UPDATE_EN [0]
Enable the triggers
0
GPO_OUTPUT_VALUE [0]
1
GPO_VALUE_ON_TRIGGER [0]
Figure 28. Block Diagram for the Digital Output Logic
8.3.11.2.1 Changing Digital Outputs on Alerts
Any given digital output can be updated in response to an alert condition on one or more analog inputs and
digital inputs. To update the digital output in response to alert conditions, the trigger must be configured and the
value must be launched on the trigger.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
21
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
8.3.11.2.1.1 Trigger
The following events can act as triggers for updating the value on the digital output:
• An alert occurs on one or more analog input channels. The digital window comparator must be enabled for
these channels.
• An alert occurs on one or more digital input channels. The digital window comparator must be enabled for
these channels.
Configure the GPOx_TRIG_EVENT_SEL register to select which channels, analog inputs, or digital inputs can
trigger an update on the digital output pin. After configuring the triggers for updating a digital output, the logic can
be enabled by configuring the corresponding bit in the GPO_TRIGGER_UPDATE_EN register.
8.3.11.2.1.2 Output Value
The digital outputs can be set to logic 1 or logic 0 in response to the triggers. The value to be updated on the
digital output when a trigger event occurs can be configured in the GPO_VALUE_ON_TRIGGER register.
8.3.12 Minimum, Maximum, and Latest Data Registers
The ADS7138 can record the minimum, maximum, and latest code (statistics registers) for every analog input
channel. To enable or re-enable recording statistics, set the STATS_EN bit in the GENERAL_CFG register.
Writing 1 to the STATS_EN bit reinitializes the statistics module, after which results from new conversions are
recorded in the statistics registers. Until a new conversion result is available, previous values can be read from
the statistics registers. Before reading the statistics registers, set STATS_EN to 0 to prevent any updates to this
register block.
8.3.13 I2C Protocol Features
8.3.13.1 General Call
On receiving a general call (00h), the device provides an acknowledge (ACK).
8.3.13.2 General Call With Software Reset
On receiving a general call (00h) followed by a software reset (06h), the device resets itself.
8.3.13.3 General Call With a Software Write to the Programmable Part of the Slave Address
On receiving a general call (00h) followed by 04h, the device reevaluates its own I2C address configured by the
ADDR pin. During this operation, the device does not respond to other I2C commands except the general-call
command.
8.3.13.4 Configuring the Device for High-Speed I2C Mode
The device can be configured in high-speed I2C mode by providing an I2C frame with one of these codes: 0x09,
0x0B, 0x0D, or 0x0F.
After receiving one of these codes, the device sets the I2C_HIGH_SPEED bit in the SYSTEM_STATUS register
and remains in high-speed I2C mode until a STOP condition is received in an I2C frame.
8.4 Device Functional Modes
Table 7 lists the functional modes supported by the ADS7138.
Table 7. Functional Modes
FUNCTIONAL
MODE
CONVERSION CONTROL
MUX CONTROL
CONV_MODE[1:0]
SEQ_MODE[1:0]
Manual
9th falling edge of SCL (ACK)
Register write to MANUAL_CHID
00b
00b
Auto-sequence
9th falling edge of SCL (ACK)
Channel sequencer
00b
01b
Autonomous
Internal to the device
Channel sequencer
01b
01b
22
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
The device powers up in manual mode (see the Manual Mode section) and can be configured into any mode
listed in Table 7 by writing the configuration registers for the desired mode.
8.4.1 Device Power-Up and Reset
On power-up, the device calculates the address from the resistors connected on the ADDR pin and the BOR bit
is set, thus indicating a power-cycle or reset event.
The device can be reset by an I2C general call (00h) followed by a software reset (06h), by setting the RST bit, or
by recycling the power on the AVDD pin.
8.4.2 Manual Mode
Manual mode allows the external host processor to directly select the analog input channel. Figure 29 lists the
steps for operating the device in manual mode.
Idle
SEQ_MODE = 0
CONV_MODE = 0
Configure channels as AIN/GPIO using PIN_CFG
Select Manual mode
(CONV_MODE = 00b, SEQ_MODE = 00b)
Configure desired Channel ID in MANUAL_CHID field
Host provides Conversion Start Frame on I2C Bus
Host provides Conversion Read Frame on I2C Bus
No
Yes
Same
Channel ID?
Manual mode with channel selection using register write
Figure 29. Device Operation in Manual Mode
Provide an I2C start or restart frame to initiate a conversion, as shown in the conversion start frame of Figure 30,
after configuring the device registers. ADC data can be read in subsequent I2C frames. The number of I2C
frames required to read conversion data depends on the output data frame size; see the Output Data Format
section for more details. A new conversion is initiated on the ninth falling edge of SCL (ACK bit) when the last
byte of output data is read.
Sample A + 1
Sample A
S
7-bit Slave Address
R
A
8 bit I2C frame
Clock stretching for conversion time
A
8 bit I2C frame
A
8 bit I2C frame
A
8 bit I2C frame
A
Clock stretching for conversion time
Data from host to device
Data from device to host
Figure 30. Starting a Conversion and Reading Data in Manual Mode
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
23
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
8.4.3 Auto-Sequence Mode
In auto-sequence mode, the internal channel sequencer switches the multiplexer to the next analog input
channel after every conversion. The desired analog input channels can be configured for sequencing in the
AUTO_SEQ_CHSEL register. To enable the channel sequencer, set SEQ_START to 1b. After every conversion,
the channel sequencer switches the multiplexer to the next analog input in ascending order. To stop the channel
sequencer from selecting channels, set SEQ_START to 0b. Figure 31 lists the conversion start and read frames
for auto-sequence mode.
Idle
SEQ_MODE = 0
CONV_MODE = 0
Configure channels as AIN/GPIO using PIN_CFG
Enable analog inputs for sequencing (AUTO_SEQ_CHSEL)
Select Auto-sequence mode (SEQ_MODE = 01b)
(optional) Configure alert conditions
(optional) Append Channel ID to data using APPEND_STATUS
Enable channel sequencing SEQ_START = 1
Host provides Conversion Start Frame on I2C Bus
Host provides Conversion Read Frame on I2C Bus
Device selects next channel according to AUTO_SEQ_CHSEL
Continue?
Yes
No
Disable channel sequencing SEQ_START = 0
Idle
Figure 31. Device Operation in Auto-Sequence Mode
8.4.4 Autonomous Mode
In autonomous mode, the device can be programmed to monitor the voltage applied on the analog input pins of
the device and generate a signal on the ALERT pin when the programmable high or low threshold values are
crossed. In this mode, the device generates the start of conversion using the internal oscillator. The first start of
conversion must be provided by the host and the device then generates the subsequent start of conversions.
Figure 32 shows the steps for configuring the operation mode to autonomous mode. Abort the ongoing sequence
by setting SEQ_START to 0b before changing the functional mode or device configuration.
24
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Idle
SEQ_MODE = 0
CONV_MODE = 0
Configure channels as AIN/GPIO using GPIO_CFG
Channel
selection
Enable analog inputs for sequencing (AUTO_SEQ_CHSEL)
Select Auto-sequence mode (SEQ_MODE = 01b)
Configure alert condition using HIGH_THRESHOLD_CHx,
LOW_THRESHOLD_CHx,EVENT_COUNT, HYSTERESIS_CHx, and
EVENT_REGION_CHx fields
Threshold & Alert
configuration
Enable analog inputs to trigger ALERT pin using ALERT_CH_SEL
Configuration
Configure ALERT pin behavior using ALERT_DRIVE and ALERT_LOGIC
Configure sampling rate of analog inputs using OSC_SEL and CLK_DIV
Set mode to autonomous monitoring (CONV_MODE = 01b)
Sampling rate
configuration
(optional) Enable averaging and min/max recording (OSR[2:0] and STATS_EN)
Enable threshold comparison (DWC_EN = 1)
Enable autonomous monitoring (SEQ_START = 1)
Active Operation
(Host can sleep)
No
ALERT?
(optional) read conversion results in
MIN_VALUE_CHx, MAX_VALUE_CHx, and
LAST_VALUE_CHx registers
Yes
Stop autonomous monitoring (SEQ_START = 0)
Disable threshold comparison (DWC_EN = 0)
ALERT Detected
Read alert flags ± EVENT_FLAG, EVENT_HIGH_FLAG, EVENT_LOW_FLAG
Clear alert flags ± EVENT_HIGH_FLAG, EVENT_LOW_FLAG
Figure 32. Configuring the Device in Autonomous Mode
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
25
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
8.5 Programming
Table 8 provides the acronyms for different conditions in an I2C frame. Table 9 lists the various command
opcodes.
Table 8. I2C Frame Acronyms
SYMBOL
DESCRIPTION
S
Start condition for the I2C frame
Sr
Restart condition for the I2C frame
P
Stop condition for the I2C frame
A
ACK (low)
N
NACK (high)
R
Read bit (high)
W
Write bit (low)
Table 9. Opcodes for Commands
OPCODE
COMMAND DESCRIPTION
0001 0000b
Single register read
0000 1000b
Single register write
0001 1000b
Set bit
0010 0000b
Clear bit
0011 0000b
Reading a continuous block of registers
0010 1000b
Writing a continuous block of registers
8.5.1 Reading Registers
The I2C master can either read a single register or a continuous block registers from the device, as described in
the Single Register Read and Reading a Continuous Block of Registers sections.
8.5.1.1 Single Register Read
To read a single register from the device, the I2C master must provide an I2C command with three frames to set
the register address for reading data. Table 9 lists the opcodes for different commands. After this command is
provided, the I2C master must provide another I2C frame (as shown in Figure 33) containing the device address
and the read bit. After this frame, the device provides the register data. The device provides the same register
data even if the host provides more clocks. To end the register read command, the master must provide a STOP
or a RESTART condition in the I2C frame.
S
7-bit Slave Address
W
A
0001 0000b
Register
Address
A
Data from host to device
A
P/Sr
S
7-bit Slave Address
R
A
Register Data
A
P/Sr
Data from device to host
NOTE: S = start, Sr = repeated start, and P = stop.
Figure 33. Reading Register Data
26
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
8.5.1.2 Reading a Continuous Block of Registers
To read a continuous block of registers, the I2C master must provide an I2C command to set the register
address. The register address is the address of the first register in the block that must be read. After this
command is provided, the I2C master must provide another I2C frame, as shown in Figure 34, containing the
device address and the read bit. After this frame, the device provides the register data. The device provides data
for the next register when more clocks are provided. When data are read from addresses that do not exist in the
register map of the device, the device returns zeros. If the device does not have any further registers to provide
data on, the device provide zeros. To end the register read command, the master must provide a STOP or a
RESTART condition in the I2C frame.
S
7-bit Slave Address
W
A
0011 0000b
A
1st Reg Address
in the Block
A
Data from host to device
P/Sr
S
7-bit Slave Address
R
A
Register Data
A
P/Sr
Data from device to host
NOTE: S = start, Sr = repeated start, and P = stop.
Figure 34. Reading a Continuous Block of Registers
8.5.2 Writing Registers
The I2C master can either write a single register or a continuous block of registers to the device, set a few bits in
a register, or clear a few bits in a register.
8.5.2.1 Single Register Write
To write a single register from the device, as shown in Figure 35, the I2C master must provide an I2C command
with four frames. The register address is the address of the register that must be written and the register data is
the value that must be written. Table 9 lists the opcodes for different commands. To end the register write
command, the master must provide a STOP or a RESTART condition in the I2C frame.
S
7-bit Slave Address
W
A
0000 1000b
Data from host to device
A
Register
Address
A
Register Data
A
P/Sr
Data from device to host
NOTE: S = start, Sr = repeated start, and P = stop.
Figure 35. Writing a Single Register
8.5.2.2 Set Bit
The I2C master must provide an I2C command with four frames, as shown in Figure 35, to set bits in a register
without changing the other bits. The register address is the address of the register that the bits must set and the
register data is the value representing the bits that must be set. Bits with a value of 1 in the register data are set
and bits with a value of 0 in the register data are not changed. Table 9 lists the opcodes for different commands.
To end this command, the master must provide a STOP or RESTART condition in the I2C frame.
8.5.2.3 Clear Bit
The I2C master must provide an I2C command with four frames, as shown in Figure 35, to clear bits in a register
without changing the other bits. The register address is the address of the register that the bits must clear and
the register data is the value representing the bits that must be cleared. Bits with a value of 1 in the register data
are cleared and bits with a value of 0 in the register data are not changed. Table 9 lists the opcodes for different
commands. To end this command, the master must provide a STOP or a RESTART condition in the I2C frame.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
27
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
8.5.2.4 Writing a Continuous Block of Registers
The I2C master must provide an I2C command, as shown in Figure 36, to write a continuous block of registers.
The register address is the address of the first register in the block that must be written. The I2C master must
provide data for registers in subsequent I2C frames in an ascending order of register addresses. Writing data to
addresses that do not exist in the register map of the device have no effect. Table 9 lists the opcodes for
different commands. If the data provided by the I2C master exceeds the address space of the device, the device
ignores the data beyond the address space. To end the register write command, the master must provide a
STOP or a RESTART condition in the I2C frame.
S
7-bit Slave Address
W
A
0010 1000b
A
1st Reg Address
in the block
Data from host to device
A
Register Data
A
P/Sr
Data from device to host
NOTE: S = start, Sr = repeated start, and P = stop.
Figure 36. Writing a Continuous Block of Registers
28
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
8.6 ADS7138 Registers
Table 10 lists the ADS7138 registers. All register offset addresses not listed in Table 10 should be considered as
reserved locations and the register contents should not be modified.
Table 10. ADS7138 Registers
Address
Acronym
0x0
SYSTEM_STATUS
0x1
GENERAL_CFG
0x2
DATA_CFG
0x3
OSR_CFG
0x4
OPMODE_CFG
0x5
PIN_CFG
0x7
GPIO_CFG
0x9
GPO_DRIVE_CFG
Register
Name
Section
SYSTEM_STATUS Register (Address = 0x0) [reset = 0x81]
GENERAL_CFG Register (Address = 0x1) [reset = 0x0]
DATA_CFG Register (Address = 0x2) [reset = 0x0]
OSR_CFG Register (Address = 0x3) [reset = 0x0]
OPMODE_CFG Register (Address = 0x4) [reset = 0x0]
PIN_CFG Register (Address = 0x5) [reset = 0x0]
GPIO_CFG Register (Address = 0x7) [reset = 0x0]
GPO_DRIVE_CFG Register (Address = 0x9) [reset = 0x0]
0xB
GPO_VALUE
0xD
GPI_VALUE
GPO_VALUE Register (Address = 0xB) [reset = 0x0]
0x10
SEQUENCE_CFG
0x11
CHANNEL_SEL
0x12
AUTO_SEQ_CH_SEL
0x14
ALERT_CH_SEL
0x16
ALERT_MAP
0x17
ALERT_PIN_CFG
0x18
EVENT_FLAG
0x1A
EVENT_HIGH_FLAG
EVENT_HIGH_FLAG Register (Address = 0x1A) [reset = 0x0]
0x1C
EVENT_LOW_FLAG
EVENT_LOW_FLAG Register (Address = 0x1C) [reset = 0x0]
0x1E
EVENT_RGN
0x20
HYSTERESIS_CH0
0x21
HIGH_TH_CH0
0x22
EVENT_COUNT_CH0
0x23
LOW_TH_CH0
0x24
HYSTERESIS_CH1
0x25
HIGH_TH_CH1
0x26
EVENT_COUNT_CH1
0x27
LOW_TH_CH1
0x28
HYSTERESIS_CH2
0x29
HIGH_TH_CH2
0x2A
EVENT_COUNT_CH2
0x2B
LOW_TH_CH2
0x2C
HYSTERESIS_CH3
0x2D
HIGH_TH_CH3
0x2E
EVENT_COUNT_CH3
0x2F
LOW_TH_CH3
0x30
HYSTERESIS_CH4
0x31
HIGH_TH_CH4
0x32
EVENT_COUNT_CH4
0x33
LOW_TH_CH4
0x34
HYSTERESIS_CH5
0x35
HIGH_TH_CH5
0x36
EVENT_COUNT_CH5
GPI_VALUE Register (Address = 0xD) [reset = 0x0]
SEQUENCE_CFG Register (Address = 0x10) [reset = 0x0]
CHANNEL_SEL Register (Address = 0x11) [reset = 0x0]
AUTO_SEQ_CH_SEL Register (Address = 0x12) [reset = 0x0]
ALERT_CH_SEL Register (Address = 0x14) [reset = 0x0]
ALERT_MAP Register (Address = 0x16) [reset = 0x0]
ALERT_PIN_CFG Register (Address = 0x17) [reset = 0x0]
EVENT_FLAG Register (Address = 0x18) [reset = 0x0]
EVENT_RGN Register (Address = 0x1E) [reset = 0x0]
HYSTERESIS_CH0 Register (Address = 0x20) [reset = 0xF0]
HIGH_TH_CH0 Register (Address = 0x21) [reset = 0xFF]
EVENT_COUNT_CH0 Register (Address = 0x22) [reset = 0x0]
LOW_TH_CH0 Register (Address = 0x23) [reset = 0x0]
HYSTERESIS_CH1 Register (Address = 0x24) [reset = 0xF0]
HIGH_TH_CH1 Register (Address = 0x25) [reset = 0xFF]
EVENT_COUNT_CH1 Register (Address = 0x26) [reset = 0x0]
LOW_TH_CH1 Register (Address = 0x27) [reset = 0x0]
HYSTERESIS_CH2 Register (Address = 0x28) [reset = 0xF0]
HIGH_TH_CH2 Register (Address = 0x29) [reset = 0xFF]
EVENT_COUNT_CH2 Register (Address = 0x2A) [reset = 0x0]
LOW_TH_CH2 Register (Address = 0x2B) [reset = 0x0]
HYSTERESIS_CH3 Register (Address = 0x2C) [reset = 0xF0]
HIGH_TH_CH3 Register (Address = 0x2D) [reset = 0xFF]
EVENT_COUNT_CH3 Register (Address = 0x2E) [reset = 0x0]
LOW_TH_CH3 Register (Address = 0x2F) [reset = 0x0]
HYSTERESIS_CH4 Register (Address = 0x30) [reset = 0xF0]
HIGH_TH_CH4 Register (Address = 0x31) [reset = 0xFF]
EVENT_COUNT_CH4 Register (Address = 0x32) [reset = 0x0]
LOW_TH_CH4 Register (Address = 0x33) [reset = 0x0]
HYSTERESIS_CH5 Register (Address = 0x34) [reset = 0xF0]
HIGH_TH_CH5 Register (Address = 0x35) [reset = 0xFF]
EVENT_COUNT_CH5 Register (Address = 0x36) [reset = 0x0]
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
29
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Table 10. ADS7138 Registers (continued)
Address
30
Acronym
Register
Name
Section
0x37
LOW_TH_CH5
0x38
HYSTERESIS_CH6
LOW_TH_CH5 Register (Address = 0x37) [reset = 0x0]
0x39
HIGH_TH_CH6
0x3A
EVENT_COUNT_CH6
0x3B
LOW_TH_CH6
0x3C
HYSTERESIS_CH7
0x3D
HIGH_TH_CH7
0x3E
EVENT_COUNT_CH7
0x3F
LOW_TH_CH7
LOW_TH_CH7 Register (Address = 0x3F) [reset = 0x0]
0x60
MAX_CH0_LSB
MAX_CH0_LSB Register (Address = 0x60) [reset = 0x0]
0x61
MAX_CH0_MSB
MAX_CH0_MSB Register (Address = 0x61) [reset = 0x0]
0x62
MAX_CH1_LSB
MAX_CH1_LSB Register (Address = 0x62) [reset = 0x0]
0x63
MAX_CH1_MSB
MAX_CH1_MSB Register (Address = 0x63) [reset = 0x0]
0x64
MAX_CH2_LSB
MAX_CH2_LSB Register (Address = 0x64) [reset = 0x0]
0x65
MAX_CH2_MSB
MAX_CH2_MSB Register (Address = 0x65) [reset = 0x0]
0x66
MAX_CH3_LSB
MAX_CH3_LSB Register (Address = 0x66) [reset = 0x0]
0x67
MAX_CH3_MSB
MAX_CH3_MSB Register (Address = 0x67) [reset = 0x0]
0x68
MAX_CH4_LSB
MAX_CH4_LSB Register (Address = 0x68) [reset = 0x0]
0x69
MAX_CH4_MSB
MAX_CH4_MSB Register (Address = 0x69) [reset = 0x0]
0x6A
MAX_CH5_LSB
MAX_CH5_LSB Register (Address = 0x6A) [reset = 0x0]
MAX_CH5_MSB Register (Address = 0x6B) [reset = 0x0]
HYSTERESIS_CH6 Register (Address = 0x38) [reset = 0xF0]
HIGH_TH_CH6 Register (Address = 0x39) [reset = 0xFF]
EVENT_COUNT_CH6 Register (Address = 0x3A) [reset = 0x0]
LOW_TH_CH6 Register (Address = 0x3B) [reset = 0x0]
HYSTERESIS_CH7 Register (Address = 0x3C) [reset = 0xF0]
HIGH_TH_CH7 Register (Address = 0x3D) [reset = 0xFF]
EVENT_COUNT_CH7 Register (Address = 0x3E) [reset = 0x0]
0x6B
MAX_CH5_MSB
0x6C
MAX_CH6_LSB
MAX_CH6_LSB Register (Address = 0x6C) [reset = 0x0]
0x6D
MAX_CH6_MSB
MAX_CH6_MSB Register (Address = 0x6D) [reset = 0x0]
0x6E
MAX_CH7_LSB
MAX_CH7_LSB Register (Address = 0x6E) [reset = 0x0]
0x6F
MAX_CH7_MSB
MAX_CH7_MSB Register (Address = 0x6F) [reset = 0x0]
0x80
MIN_CH0_LSB
MIN_CH0_LSB Register (Address = 0x80) [reset = 0xFF]
0x81
MIN_CH0_MSB
MIN_CH0_MSB Register (Address = 0x81) [reset = 0xFF]
0x82
MIN_CH1_LSB
MIN_CH1_LSB Register (Address = 0x82) [reset = 0xFF]
0x83
MIN_CH1_MSB
MIN_CH1_MSB Register (Address = 0x83) [reset = 0xFF]
0x84
MIN_CH2_LSB
MIN_CH2_LSB Register (Address = 0x84) [reset = 0xFF]
0x85
MIN_CH2_MSB
MIN_CH2_MSB Register (Address = 0x85) [reset = 0xFF]
0x86
MIN_CH3_LSB
MIN_CH3_LSB Register (Address = 0x86) [reset = 0xFF]
0x87
MIN_CH3_MSB
MIN_CH3_MSB Register (Address = 0x87) [reset = 0xFF]
0x88
MIN_CH4_LSB
MIN_CH4_LSB Register (Address = 0x88) [reset = 0xFF]
0x89
MIN_CH4_MSB
MIN_CH4_MSB Register (Address = 0x89) [reset = 0xFF]
0x8A
MIN_CH5_LSB
MIN_CH5_LSB Register (Address = 0x8A) [reset = 0xFF]
MIN_CH5_MSB Register (Address = 0x8B) [reset = 0xFF]
0x8B
MIN_CH5_MSB
0x8C
MIN_CH6_LSB
MIN_CH6_LSB Register (Address = 0x8C) [reset = 0xFF]
0x8D
MIN_CH6_MSB
MIN_CH6_MSB Register (Address = 0x8D) [reset = 0xFF]
0x8E
MIN_CH7_LSB
MIN_CH7_LSB Register (Address = 0x8E) [reset = 0xFF]
0x8F
MIN_CH7_MSB
0xA0
RECENT_CH0_LSB
RECENT_CH0_LSB Register (Address = 0xA0) [reset = 0x0]
MIN_CH7_MSB Register (Address = 0x8F) [reset = 0xFF]
0xA1
RECENT_CH0_MSB
RECENT_CH0_MSB Register (Address = 0xA1) [reset = 0x0]
0xA2
RECENT_CH1_LSB
RECENT_CH1_LSB Register (Address = 0xA2) [reset = 0x0]
0xA3
RECENT_CH1_MSB
RECENT_CH1_MSB Register (Address = 0xA3) [reset = 0x0]
0xA4
RECENT_CH2_LSB
RECENT_CH2_LSB Register (Address = 0xA4) [reset = 0x0]
0xA5
RECENT_CH2_MSB
RECENT_CH2_MSB Register (Address = 0xA5) [reset = 0x0]
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Table 10. ADS7138 Registers (continued)
Address
Acronym
Register
Name
Section
0xA6
RECENT_CH3_LSB
RECENT_CH3_LSB Register (Address = 0xA6) [reset = 0x0]
0xA7
RECENT_CH3_MSB
RECENT_CH3_MSB Register (Address = 0xA7) [reset = 0x0]
0xA8
RECENT_CH4_LSB
RECENT_CH4_LSB Register (Address = 0xA8) [reset = 0x0]
RECENT_CH4_MSB Register (Address = 0xA9) [reset = 0x0]
0xA9
RECENT_CH4_MSB
0xAA
RECENT_CH5_LSB
RECENT_CH5_LSB Register (Address = 0xAA) [reset = 0x0]
0xAB
RECENT_CH5_MSB
RECENT_CH5_MSB Register (Address = 0xAB) [reset = 0x0]
0xAC
RECENT_CH6_LSB
RECENT_CH6_LSB Register (Address = 0xAC) [reset = 0x0]
0xAD
RECENT_CH6_MSB
RECENT_CH6_MSB Register (Address = 0xAD) [reset = 0x0]
0xAE
RECENT_CH7_LSB
RECENT_CH7_LSB Register (Address = 0xAE) [reset = 0x0]
0xAF
RECENT_CH7_MSB
RECENT_CH7_MSB Register (Address = 0xAF) [reset = 0x0]
0xC3
GPO0_TRIG_EVENT_SEL
GPO0_TRIG_EVENT_SEL Register (Address = 0xC3) [reset = 0x2]
0xC5
GPO1_TRIG_EVENT_SEL
GPO1_TRIG_EVENT_SEL Register (Address = 0xC5) [reset = 0x2]
0xC7
GPO2_TRIG_EVENT_SEL
GPO2_TRIG_EVENT_SEL Register (Address = 0xC7) [reset = 0x2]
0xC9
GPO3_TRIG_EVENT_SEL
GPO3_TRIG_EVENT_SEL Register (Address = 0xC9) [reset = 0x2]
0xCB
GPO4_TRIG_EVENT_SEL
GPO4_TRIG_EVENT_SEL Register (Address = 0xCB) [reset = 0x2]
0xCD
GPO5_TRIG_EVENT_SEL
GPO5_TRIG_EVENT_SEL Register (Address = 0xCD) [reset = 0x2]
0xCF
GPO6_TRIG_EVENT_SEL
GPO6_TRIG_EVENT_SEL Register (Address = 0xCF) [reset = 0x2]
0xD1
GPO7_TRIG_EVENT_SEL
GPO7_TRIG_EVENT_SEL Register (Address = 0xD1) [reset = 0x2]
0xE9
GPO_TRIGGER_CFG
0xEB
GPO_VALUE_TRIG
GPO_TRIGGER_CFG Register (Address = 0xE9) [reset = 0x0]
GPO_VALUE_TRIG Register (Address = 0xEB) [reset = 0x0]
Complex bit access types are encoded to fit into small table cells. Table 11 shows the codes that are used for
access types in this section.
Table 11. ADS7138 Access Type Codes
Access Type
Code
Description
R
Read
W
Write
Read Type
R
Write Type
W
Reset or Default Value
-n
Value after reset or the default
value
Register Array Variables
i,j,k,l,m,n
When these variables are used in
a register name, an offset, or an
address, they refer to the value of
a register array where the register
is part of a group of repeating
registers. The register groups form
a hierarchical structure and the
array is represented with a
formula.
y
When this variable is used in a
register name, an offset, or an
address it refers to the value of a
register array.
8.6.1 SYSTEM_STATUS Register (Address = 0x0) [reset = 0x81]
SYSTEM_STATUS is shown in Figure 37 and described in Table 12.
Return to the Summary Table.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
31
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Figure 37. SYSTEM_STATUS Register
7
RSVD
6
SEQ_STATUS
5
I2C_SPEED
4
RESERVED
3
OSR_DONE
R-1b
R-0b
R-0b
R-0b
R/W-0b
2
CRC_ERR_FU
SE
R-0b
1
CRC_ERR_IN
0
BOR
R/W-0b
R/W-1b
Table 12. SYSTEM_STATUS Register Field Descriptions
Bit
Field
Type
Reset
Description
7
RSVD
R
1b
Reads return 1b.
6
SEQ_STATUS
R
0b
Status of the channel sequencer.
0b = Sequence stopped
1b = Sequence in progress
2
5
I C_SPEED
R
0b
I2C high-speed status.
0b = I2C bus is not in high-speed mode.
1b = I2C bus is in high-speed mode.
4
RESERVED
R
0b
Reserved. Reads return 0.
3
OSR_DONE
R/W
0b
Averaging status. Clear this bit by writing 1b to this bit.
0b = Averaging in progress or not started; average result is not
ready.
1b = Averaging complete; average result is ready.
2
CRC_ERR_FUSE
R
0b
Device power-up configuration CRC check status. To re-evaluate
this bit, software reset the device or power cycle AVDD.
0b = No problems detected in power-up configuration.
1b = Device configuration not loaded correctly.
1
CRC_ERR_IN
R/W
0b
Status of CRC check on incoming data. Write 1b to clear this error
flag.
0b = No CRC error.
1b = CRC error detected. All register writes, except to addresses
0x00 and 0x01, are blocked.
0
BOR
R/W
1b
Brown out reset indicator. This bit is set if brown out condition occurs
or device is power cycled. Write 1b to this bit to clear the flag.
0b = No brown out from last time this bit was cleared.
1b = Brown out condition detected or device power cycled.
8.6.2 GENERAL_CFG Register (Address = 0x1) [reset = 0x0]
GENERAL_CFG is shown in Figure 38 and described in Table 13.
Return to the Summary Table.
Figure 38. GENERAL_CFG Register
7
RESERVED
R-0b
6
CRC_EN
R/W-0b
5
STATS_EN
R/W-0b
4
DWC_EN
R/W-0b
3
CNVST
W-0b
2
CH_RST
R/W-0b
1
CAL
R/W-0b
0
RST
W-0b
Table 13. GENERAL_CFG Register Field Descriptions
Bit
Field
Type
Reset
Description
7
RESERVED
R
0b
Reserved. Reads return 0.
6
CRC_EN
R/W
0b
Enable or disable the CRC on device interface.
0b = CRC module disabled.
1b = CRC appended to data output. CRC check is enabled on
incoming data.
32
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Table 13. GENERAL_CFG Register Field Descriptions (continued)
Bit
5
Field
Type
Reset
Description
STATS_EN
R/W
0b
Enable or disable the statistics module to update minimu, maximum,
and latest output code registers.
0b = Statistics registers are not updated.
1b = Clear statistics registers and conitnue updating with new
conversion results.
4
DWC_EN
R/W
0b
Enable or disable the digital window comparator.
0b = Reset or disable the digital window comparator.
1b = Enable the digital window comparator.
3
CNVST
W
0b
Control start conversion on selected analog input. Readback of this
bit returns 0b.
0b = Normal operation; conversions starts on the 9th falling edge of
I2C frame. Device stretches SCL until end of conversion or
completion of averaging.
1b = Initiate start of conversion. Device does not stretch SCL until
end of conversion or completion of averaging.
2
CH_RST
R/W
0b
Force all channels to be analog inputs.
0b = Normal operation.
1b = All channels are configured as analog inputs irrespective of
configuration in other registers.
1
CAL
R/W
0b
Calibrate ADC offset.
0b = Normal operation.
1b = ADC offset is calibrated. After calibration is complete, this bit is
set to 0b.
0
RST
W
0b
Software reset all registers to default values.
0b = Normal operation.
1b = Device is reset. After reset is complete, this bit is set to 0b and
BOR bit is set to 1b.
8.6.3 DATA_CFG Register (Address = 0x2) [reset = 0x0]
DATA_CFG is shown in Figure 39 and described in Table 14.
Return to the Summary Table.
Figure 39. DATA_CFG Register
7
FIX_PAT
R/W-0b
6
RESERVED
R-0b
5
4
APPEND_STATUS[1:0]
R/W-0b
3
2
1
0
RESERVED
R-0b
Table 14. DATA_CFG Register Field Descriptions
Bit
7
Field
Type
Reset
Description
FIX_PAT
R/W
0b
Device will output fixed data bits, which can be helpful for debugging
communication with the device.
0b = Normal operation.
1b = Device outputs fixed code 0xA5A repeatitively when reading
ADC data.
6
5-4
RESERVED
R
0b
Reserved. Reads return 0.
APPEND_STATUS[1:0]
R/W
0b
Append 4-bit channel ID or status flags to output data.
0b = Channel ID and status flags are not appended to ADC data.
1b = 4-bit channel ID is appended to ADC data.
10b = 4-bit status flags are appended to ADC data.
11b = Reserved.
3-0
RESERVED
R
0b
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
33
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
8.6.4 OSR_CFG Register (Address = 0x3) [reset = 0x0]
OSR_CFG is shown in Figure 40 and described in Table 15.
Return to the Summary Table.
Figure 40. OSR_CFG Register
7
6
5
RESERVED
R-0b
4
3
2
1
OSR[2:0]
R/W-0b
0
Table 15. OSR_CFG Register Field Descriptions
Bit
Field
Type
Reset
Description
7-3
RESERVED
R
0b
Reserved. Reads return 0.
2-0
OSR[2:0]
R/W
0b
Selects the oversampling ratio for ADC conversion result.
0b = No averaging
1b = 2 samples
10b = 4 samples
11b = 8 samples
100b = 16 samples
101b = 32 samples
110b = 64 samples
111b = 128 samples
8.6.5 OPMODE_CFG Register (Address = 0x4) [reset = 0x0]
OPMODE_CFG is shown in Figure 41 and described in Table 16.
Return to the Summary Table.
Figure 41. OPMODE_CFG Register
7
CONV_ON_ER
R
R/W-0b
6
5
CONV_MODE[1:0]
4
OSC_SEL
R/W-0b
R/W-0b
3
2
1
0
CLK_DIV[3:0]
R/W-0b
Table 16. OPMODE_CFG Register Field Descriptions
Bit
7
Field
Type
Reset
Description
CONV_ON_ERR
R/W
0b
Control continuation of autonomous modes if CRC error is detected
on communication interface.
0b = If CRC error is detected, device continues channel sequencing
and pin configuration is retained. See the CRC_ERR_IN bit for more
details.
1b = If CRC error is detected, device changes all channels to analog
inputs and channel sequencing will be paused until CRC_ERR_IN =
1b. After clearing CRC_ERR_IN flag, device resumes channel
sequencing and pin confguration is restored.
6-5
CONV_MODE[1:0]
R/W
0b
These bits set the mode of conversion of the ADC.
0b = Manual mode; conversions are initiated by host.
1b = Autonomous mode; conversions are initiated by internal state
machine.
4
OSC_SEL
R/W
0b
Selects the oscillator for internal timing generation.
0b = High-speed oscillator.
1b = Low-power oscillator.
3-0
34
CLK_DIV[3:0]
R/W
0b
Sampling speed control in autonomous monitoring mode
(CONV_MODE = 01b). See the section on oscillator and timing
control for details.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
8.6.6 PIN_CFG Register (Address = 0x5) [reset = 0x0]
PIN_CFG is shown in Figure 42 and described in Table 17.
Return to the Summary Table.
Figure 42. PIN_CFG Register
7
6
5
4
3
2
1
0
PIN_CFG[7:0]
R/W-0b
Table 17. PIN_CFG Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
PIN_CFG[7:0]
R/W
0b
Configure device channels AIN/GPIO[7:0] as analog inputs or
GPIOs.
0b = Channel is configured as analog input.
1b = Channel is configured as GPIO.
8.6.7 GPIO_CFG Register (Address = 0x7) [reset = 0x0]
GPIO_CFG is shown in Figure 43 and described in Table 18.
Return to the Summary Table.
Figure 43. GPIO_CFG Register
7
6
5
4
3
2
1
0
GPIO_CFG[7:0]
R/W-0b
Table 18. GPIO_CFG Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
GPIO_CFG[7:0]
R/W
0b
Configure GPIO[7:0] as either digital inputs or digital outputs.
0b = GPIO is configured as digital input.
1b = GPIO is configured as digital output.
8.6.8 GPO_DRIVE_CFG Register (Address = 0x9) [reset = 0x0]
GPO_DRIVE_CFG is shown in Figure 44 and described in Table 19.
Return to the Summary Table.
Figure 44. GPO_DRIVE_CFG Register
7
6
5
4
3
GPO_DRIVE_CFG[7:0]
R/W-0b
2
1
0
Table 19. GPO_DRIVE_CFG Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
GPO_DRIVE_CFG[7:0]
R/W
0b
Configure digital outputs GPO[7:0] as either open-drain or push-pull
outputs.
0b = Digital output is open-drain; connect external pullup resistor.
1b = Push-pull driver is used for digital output.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
35
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
8.6.9 GPO_VALUE Register (Address = 0xB) [reset = 0x0]
GPO_VALUE is shown in Figure 45 and described in Table 20.
Return to the Summary Table.
Figure 45. GPO_VALUE Register
7
6
5
4
3
GPO_VALUE[7:0]
R/W-0b
2
1
0
Table 20. GPO_VALUE Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
GPO_VALUE[7:0]
R/W
0b
Logic level to be set on digital outputs GPO[7:0].
0b = Digital output set to logic 0.
1b = Digital output set to logic 1.
8.6.10 GPI_VALUE Register (Address = 0xD) [reset = 0x0]
GPI_VALUE is shown in Figure 46 and described in Table 21.
Return to the Summary Table.
Figure 46. GPI_VALUE Register
7
6
5
4
3
GPI_VALUE[7:0]
R-0b
2
1
0
Table 21. GPI_VALUE Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
GPI_VALUE[7:0]
R
0b
Readback the logic level on GPIO[7:0].
0b = GPIO is at logic 0.
1b = GPIO is at logic 1.
8.6.11 SEQUENCE_CFG Register (Address = 0x10) [reset = 0x0]
SEQUENCE_CFG is shown in Figure 47 and described in Table 22.
Return to the Summary Table.
Figure 47. SEQUENCE_CFG Register
7
6
RESERVED
R-0b
5
4
SEQ_START
R/W-0b
3
2
RESERVED
R-0b
1
0
SEQ_MODE[1:0]
R/W-0b
Table 22. SEQUENCE_CFG Register Field Descriptions
Bit
Field
Type
Reset
Description
7-5
RESERVED
R
0b
Reserved. Reads return 0.
4
SEQ_START
R/W
0b
Control for start of channel sequence when using auto sequence
mode (SEQ_MODE = 01b).
0b = Stop channel sequencing.
1b = Start channel sequencing in ascending order for channels
enabled in AUTO_SEQ_CH_SEL register.
3-2
36
RESERVED
R
0b
Reserved. Reads return 0.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Table 22. SEQUENCE_CFG Register Field Descriptions (continued)
Bit
Field
Type
Reset
Description
1-0
SEQ_MODE[1:0]
R/W
0b
Selects the mode of scanning of analog input channels.
0b = Manual sequence mode; channel selected by MANUAL_CHID
field.
1b = Auto sequence mode; channel selected by internal channel
sequencer.
10b = Reserved.
11b = Reserved.
8.6.12 CHANNEL_SEL Register (Address = 0x11) [reset = 0x0]
CHANNEL_SEL is shown in Figure 48 and described in Table 23.
Return to the Summary Table.
Figure 48. CHANNEL_SEL Register
7
6
5
4
3
RESERVED
R-0b
2
1
MANUAL_CHID[3:0]
R/W-0b
0
Table 23. CHANNEL_SEL Register Field Descriptions
Bit
Field
Type
Reset
Description
7-4
RESERVED
R
0b
Reserved. Reads return 0.
3-0
MANUAL_CHID[3:0]
R/W
0b
In manual mode (SEQ_MODE = 00b), this field contains the 4-bit
channel ID of the analog input channel for next ADC conversion. For
valid ADC data, the selected channel must not be configured as
GPIO in PIN_CFG register.
0b = AIN0
1b = AIN1
10b = AIN2
11b = AIN3
100b = AIN4
101b = AIN5
110b = AIN6
111b = AIN7
1000b = Reserved.
8.6.13 AUTO_SEQ_CH_SEL Register (Address = 0x12) [reset = 0x0]
AUTO_SEQ_CH_SEL is shown in Figure 49 and described in Table 24.
Return to the Summary Table.
Figure 49. AUTO_SEQ_CH_SEL Register
7
6
5
4
3
AUTO_SEQ_CH_SEL[7:0]
R/W-0b
2
1
0
Table 24. AUTO_SEQ_CH_SEL Register Field Descriptions
Bit
Field
7-0
AUTO_SEQ_CH_SEL[7:0] R/W
Type
Reset
Description
0b
Select analog input channels AIN[7:0] in for auto sequencing mode.
0b = Analog input channel is not enabled in scanning sequence.
1b = Analog input channel is enabled in scanning sequence.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
37
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
8.6.14 ALERT_CH_SEL Register (Address = 0x14) [reset = 0x0]
ALERT_CH_SEL is shown in Figure 50 and described in Table 25.
Return to the Summary Table.
Figure 50. ALERT_CH_SEL Register
7
6
5
4
3
ALERT_CH_SEL[7:0]
R/W-0b
2
1
0
Table 25. ALERT_CH_SEL Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
ALERT_CH_SEL[7:0]
R/W
0b
Select channels for which the alert flags can assert the ALERT pin.
0b = Alert flags for this channel do not assert the ALERT pin.
1b = Alert flags for this channel assert the ALERT pin.
8.6.15 ALERT_MAP Register (Address = 0x16) [reset = 0x0]
ALERT_MAP is shown in Figure 51 and described in Table 26.
Return to the Summary Table.
Figure 51. ALERT_MAP Register
7
6
5
4
RESERVED
R-0b
3
2
1
0
ALERT_CRCIN
R/W-0b
Table 26. ALERT_MAP Register Field Descriptions
Bit
Field
Type
Reset
Description
7-1
RESERVED
R
0b
Reserved. Reads return 0.
ALERT_CRCIN
R/W
0b
Enable or disable the alert notification for CRC error on input data
(CRCERR_IN = 1b).
0
0b = ALERT pin is not asserted when CRCERR_IN = 1b.
1b = ALERT pin is asserted when CRCERR_IN = 1b. Clear
CRCERR_IN for deasserting the ALERT pin.
8.6.16 ALERT_PIN_CFG Register (Address = 0x17) [reset = 0x0]
ALERT_PIN_CFG is shown in Figure 52 and described in Table 27.
Return to the Summary Table.
Figure 52. ALERT_PIN_CFG Register
7
6
5
RESERVED
R-0b
4
3
2
ALERT_DRIVE
R/W-0b
1
0
ALERT_LOGIC[1:0]
R/W-0b
Table 27. ALERT_PIN_CFG Register Field Descriptions
Bit
Field
Type
Reset
Description
7-3
RESERVED
R
0b
Reserved. Reads return 0.
ALERT_DRIVE
R/W
0b
Configure output drive of the ALERT pin.
2
0b = Open-drain output. Connect external pullup resistor.
1b = Push-pull output.
38
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Table 27. ALERT_PIN_CFG Register Field Descriptions (continued)
Bit
Field
Type
Reset
Description
1-0
ALERT_LOGIC[1:0]
R/W
0b
Configure how ALERT pin is asserted.
0b = Active low.
1b = Active high.
10b = Pulsed low (one logic low pulse one time per alert flag).
11b = Pulsed high (one logic high pulse one time per alert flag).
8.6.17 EVENT_FLAG Register (Address = 0x18) [reset = 0x0]
EVENT_FLAG is shown in Figure 53 and described in Table 28.
Return to the Summary Table.
Figure 53. EVENT_FLAG Register
7
6
5
4
3
EVENT_FLAG[7:0]
R-0b
2
1
0
Table 28. EVENT_FLAG Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
EVENT_FLAG[7:0]
R
0b
Alert flags indicating digital window comparator status for CH[7:0].
Clear individual bits of EVENT_HIGH_FLAG or EVENT_LOW_FLAG
registers to clear the corresponding alert flag.
0b = Event condition not detected.
1b = Event condition detected.
8.6.18 EVENT_HIGH_FLAG Register (Address = 0x1A) [reset = 0x0]
EVENT_HIGH_FLAG is shown in Figure 54 and described in Table 29.
Return to the Summary Table.
Figure 54. EVENT_HIGH_FLAG Register
7
6
5
4
3
EVENT_HIGH_FLAG[7:0]
R/W-0b
2
1
0
Table 29. EVENT_HIGH_FLAG Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
EVENT_HIGH_FLAG[7:0]
R/W
0b
Alert flag corresponding to high threshold of analog input or logic 1
on digital input on CH[7:0]. Write 1b to clear this flag.
0b = No alert condition detected.
1b = Either high threshold was exceeded (analog input) or logic 1
was detected (digital input).
8.6.19 EVENT_LOW_FLAG Register (Address = 0x1C) [reset = 0x0]
EVENT_LOW_FLAG is shown in Figure 55 and described in Table 30.
Return to the Summary Table.
Figure 55. EVENT_LOW_FLAG Register
7
6
5
4
3
EVENT_LOW_FLAG[7:0]
R/W-0b
2
1
0
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
39
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Table 30. EVENT_LOW_FLAG Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
EVENT_LOW_FLAG[7:0]
R/W
0b
Alert flag corresponding to low threshold of analog input or logic 0 on
digital input on CH[7:0]. Write 1b to clear this flag.
0b = No Event condition detected.
1b = Either low threshold was exceeded (analog input) or logic 0 was
detected (digital input).
8.6.20 EVENT_RGN Register (Address = 0x1E) [reset = 0x0]
EVENT_RGN is shown in Figure 56 and described in Table 31.
Return to the Summary Table.
Figure 56. EVENT_RGN Register
7
6
5
4
3
EVENT_RGN[7:0]
R/W-0b
2
1
0
Table 31. EVENT_RGN Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
EVENT_RGN[7:0]
R/W
0b
Choice of region used in monitoring analog and digital inputs
CH[7:0].
0b = Alert flag is set if: (conversion result < low threshold) or
(conversion result > high threshold). For digital inputs, logic 1 sets
the alert flag.
1b = Alert flag is set if: (low threshold > conversion result < high
threshold). For digital inputs, logic 0 sets the alert flag.
8.6.21 HYSTERESIS_CH0 Register (Address = 0x20) [reset = 0xF0]
HYSTERESIS_CH0 is shown in Figure 57 and described in Table 32.
Return to the Summary Table.
Figure 57. HYSTERESIS_CH0 Register
7
6
5
HIGH_THRESHOLD_CH0_LSB[3:0]
R/W-1111b
4
3
2
1
HYSTERESIS_CH0[3:0]
R/W-0b
0
Table 32. HYSTERESIS_CH0 Register Field Descriptions
Bit
Field
Reset
Description
7-4
HIGH_THRESHOLD_CH0 R/W
_LSB[3:0]
Type
1111b
Lower 4-bits of high threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
3-0
HYSTERESIS_CH0[3:0]
0b
4-bit hysteresis for high and low thresholds. This 4-bit hysteris is left
shifted 3 times and applied on the lower 7-bits of the threshold. Total
hysteresis = 7-bits [4-bits, 000b]
R/W
8.6.22 HIGH_TH_CH0 Register (Address = 0x21) [reset = 0xFF]
HIGH_TH_CH0 is shown in Figure 58 and described in Table 33.
Return to the Summary Table.
40
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Figure 58. HIGH_TH_CH0 Register
7
6
5
4
3
HIGH_THRESHOLD_CH0_MSB[7:0]
R/W-11111111b
2
1
0
Table 33. HIGH_TH_CH0 Register Field Descriptions
Bit
Field
Type
7-0
HIGH_THRESHOLD_CH0 R/W
_MSB[7:0]
Reset
Description
11111111b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
8.6.23 EVENT_COUNT_CH0 Register (Address = 0x22) [reset = 0x0]
EVENT_COUNT_CH0 is shown in Figure 59 and described in Table 34.
Return to the Summary Table.
Figure 59. EVENT_COUNT_CH0 Register
7
6
5
LOW_THRESHOLD_CH0_LSB[3:0]
R/W-0b
4
3
2
1
EVENT_COUNT_CH0[3:0]
R/W-0b
0
Table 34. EVENT_COUNT_CH0 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-4
LOW_THRESHOLD_CH0
_LSB[3:0]
R/W
0b
Lower 4-bits of low threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
3-0
EVENT_COUNT_CH0[3:0 R/W
]
0b
Configuration for checking 'n+1' consecutive samples above
threshold before setting event flag.
8.6.24 LOW_TH_CH0 Register (Address = 0x23) [reset = 0x0]
LOW_TH_CH0 is shown in Figure 60 and described in Table 35.
Return to the Summary Table.
Figure 60. LOW_TH_CH0 Register
7
6
5
4
3
LOW_THRESHOLD_CH0_MSB[7:0]
R/W-0b
2
1
0
Table 35. LOW_TH_CH0 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
LOW_THRESHOLD_CH0
_MSB[7:0]
R/W
0b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
8.6.25 HYSTERESIS_CH1 Register (Address = 0x24) [reset = 0xF0]
HYSTERESIS_CH1 is shown in Figure 61 and described in Table 36.
Return to the Summary Table.
Figure 61. HYSTERESIS_CH1 Register
7
6
5
HIGH_THRESHOLD_CH1_LSB[3:0]
R/W-1111b
4
3
2
1
HYSTERESIS_CH1[3:0]
R/W-0b
0
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
41
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Table 36. HYSTERESIS_CH1 Register Field Descriptions
Bit
Field
Reset
Description
7-4
HIGH_THRESHOLD_CH1 R/W
_LSB[3:0]
Type
1111b
Lower 4-bits of high threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
3-0
HYSTERESIS_CH1[3:0]
0b
4-bit hysteresis for high and low thresholds. This 4-bit hysteris is left
shifted 3 times and applied on the lower 7-bits of the threshold. Total
hysteresis = 7-bits [4-bits, 000b]
R/W
8.6.26 HIGH_TH_CH1 Register (Address = 0x25) [reset = 0xFF]
HIGH_TH_CH1 is shown in Figure 62 and described in Table 37.
Return to the Summary Table.
Figure 62. HIGH_TH_CH1 Register
7
6
5
4
3
HIGH_THRESHOLD_CH1_MSB[7:0]
R/W-11111111b
2
1
0
Table 37. HIGH_TH_CH1 Register Field Descriptions
Bit
Field
7-0
HIGH_THRESHOLD_CH1 R/W
_MSB[7:0]
Type
Reset
Description
11111111b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
8.6.27 EVENT_COUNT_CH1 Register (Address = 0x26) [reset = 0x0]
EVENT_COUNT_CH1 is shown in Figure 63 and described in Table 38.
Return to the Summary Table.
Figure 63. EVENT_COUNT_CH1 Register
7
6
5
LOW_THRESHOLD_CH1_LSB[3:0]
R/W-0b
4
3
2
1
EVENT_COUNT_CH1[3:0]
R/W-0b
0
Table 38. EVENT_COUNT_CH1 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-4
LOW_THRESHOLD_CH1
_LSB[3:0]
R/W
0b
Lower 4-bits of low threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
3-0
EVENT_COUNT_CH1[3:0 R/W
]
0b
Configuration for checking 'n+1' consecutive samples above
threshold before setting event flag.
8.6.28 LOW_TH_CH1 Register (Address = 0x27) [reset = 0x0]
LOW_TH_CH1 is shown in Figure 64 and described in Table 39.
Return to the Summary Table.
Figure 64. LOW_TH_CH1 Register
7
42
6
5
4
3
LOW_THRESHOLD_CH1_MSB[7:0]
R/W-0b
Submit Documentation Feedback
2
1
0
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Table 39. LOW_TH_CH1 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
LOW_THRESHOLD_CH1
_MSB[7:0]
R/W
0b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
8.6.29 HYSTERESIS_CH2 Register (Address = 0x28) [reset = 0xF0]
HYSTERESIS_CH2 is shown in Figure 65 and described in Table 40.
Return to the Summary Table.
Figure 65. HYSTERESIS_CH2 Register
7
6
5
HIGH_THRESHOLD_CH2_LSB[3:0]
R/W-1111b
4
3
2
1
HYSTERESIS_CH2[3:0]
R/W-0b
0
Table 40. HYSTERESIS_CH2 Register Field Descriptions
Bit
Field
7-4
3-0
Type
Reset
Description
HIGH_THRESHOLD_CH2 R/W
_LSB[3:0]
1111b
Lower 4-bits of high threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
HYSTERESIS_CH2[3:0]
0b
4-bit hysteresis for high and low thresholds. This 4-bit hysteris is left
shifted 3 times and applied on the lower 7-bits of the threshold. Total
hysteresis = 7-bits [4-bits, 000b]
R/W
8.6.30 HIGH_TH_CH2 Register (Address = 0x29) [reset = 0xFF]
HIGH_TH_CH2 is shown in Figure 66 and described in Table 41.
Return to the Summary Table.
Figure 66. HIGH_TH_CH2 Register
7
6
5
4
3
HIGH_THRESHOLD_CH2_MSB[7:0]
R/W-11111111b
2
1
0
Table 41. HIGH_TH_CH2 Register Field Descriptions
Bit
Field
7-0
HIGH_THRESHOLD_CH2 R/W
_MSB[7:0]
Type
Reset
Description
11111111b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
8.6.31 EVENT_COUNT_CH2 Register (Address = 0x2A) [reset = 0x0]
EVENT_COUNT_CH2 is shown in Figure 67 and described in Table 42.
Return to the Summary Table.
Figure 67. EVENT_COUNT_CH2 Register
7
6
5
LOW_THRESHOLD_CH2_LSB[3:0]
R/W-0b
4
3
2
1
EVENT_COUNT_CH2[3:0]
R/W-0b
0
Table 42. EVENT_COUNT_CH2 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-4
LOW_THRESHOLD_CH2
_LSB[3:0]
R/W
0b
Lower 4-bits of low threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
43
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Table 42. EVENT_COUNT_CH2 Register Field Descriptions (continued)
Bit
Field
3-0
EVENT_COUNT_CH2[3:0 R/W
]
Type
Reset
Description
0b
Configuration for checking 'n+1' consecutive samples above
threshold before setting event flag.
8.6.32 LOW_TH_CH2 Register (Address = 0x2B) [reset = 0x0]
LOW_TH_CH2 is shown in Figure 68 and described in Table 43.
Return to the Summary Table.
Figure 68. LOW_TH_CH2 Register
7
6
5
4
3
LOW_THRESHOLD_CH2_MSB[7:0]
R/W-0b
2
1
0
Table 43. LOW_TH_CH2 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
LOW_THRESHOLD_CH2
_MSB[7:0]
R/W
0b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
8.6.33 HYSTERESIS_CH3 Register (Address = 0x2C) [reset = 0xF0]
HYSTERESIS_CH3 is shown in Figure 69 and described in Table 44.
Return to the Summary Table.
Figure 69. HYSTERESIS_CH3 Register
7
6
5
HIGH_THRESHOLD_CH3_LSB[3:0]
R/W-1111b
4
3
2
1
HYSTERESIS_CH3[3:0]
R/W-0b
0
Table 44. HYSTERESIS_CH3 Register Field Descriptions
Bit
Field
7-4
3-0
Type
Reset
Description
HIGH_THRESHOLD_CH3 R/W
_LSB[3:0]
1111b
Lower 4-bits of high threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
HYSTERESIS_CH3[3:0]
0b
4-bit hysteresis for high and low thresholds. This 4-bit hysteris is left
shifted 3 times and applied on the lower 7-bits of the threshold. Total
hysteresis = 7-bits [4-bits, 000b]
R/W
8.6.34 HIGH_TH_CH3 Register (Address = 0x2D) [reset = 0xFF]
HIGH_TH_CH3 is shown in Figure 70 and described in Table 45.
Return to the Summary Table.
Figure 70. HIGH_TH_CH3 Register
7
6
5
4
3
HIGH_THRESHOLD_CH3_MSB[7:0]
R/W-11111111b
2
1
0
Table 45. HIGH_TH_CH3 Register Field Descriptions
44
Bit
Field
7-0
HIGH_THRESHOLD_CH3 R/W
_MSB[7:0]
Type
Reset
Description
11111111b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
8.6.35 EVENT_COUNT_CH3 Register (Address = 0x2E) [reset = 0x0]
EVENT_COUNT_CH3 is shown in Figure 71 and described in Table 46.
Return to the Summary Table.
Figure 71. EVENT_COUNT_CH3 Register
7
6
5
LOW_THRESHOLD_CH3_LSB[3:0]
R/W-0b
4
3
2
1
EVENT_COUNT_CH3[3:0]
R/W-0b
0
Table 46. EVENT_COUNT_CH3 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-4
LOW_THRESHOLD_CH3
_LSB[3:0]
R/W
0b
Lower 4-bits of low threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
3-0
EVENT_COUNT_CH3[3:0 R/W
]
0b
Configuration for checking 'n+1' consecutive samples above
threshold before setting event flag.
8.6.36 LOW_TH_CH3 Register (Address = 0x2F) [reset = 0x0]
LOW_TH_CH3 is shown in Figure 72 and described in Table 47.
Return to the Summary Table.
Figure 72. LOW_TH_CH3 Register
7
6
5
4
3
LOW_THRESHOLD_CH3_MSB[7:0]
R/W-0b
2
1
0
Table 47. LOW_TH_CH3 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
LOW_THRESHOLD_CH3
_MSB[7:0]
R/W
0b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
8.6.37 HYSTERESIS_CH4 Register (Address = 0x30) [reset = 0xF0]
HYSTERESIS_CH4 is shown in Figure 73 and described in Table 48.
Return to the Summary Table.
Figure 73. HYSTERESIS_CH4 Register
7
6
5
HIGH_THRESHOLD_CH4_LSB[3:0]
R/W-1111b
4
3
2
1
HYSTERESIS_CH4[3:0]
R/W-0b
0
Table 48. HYSTERESIS_CH4 Register Field Descriptions
Bit
Field
7-4
3-0
Type
Reset
Description
HIGH_THRESHOLD_CH4 R/W
_LSB[3:0]
1111b
Lower 4-bits of high threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
HYSTERESIS_CH4[3:0]
0b
4-bit hysteresis for high and low thresholds. This 4-bit hysteris is left
shifted 3 times and applied on the lower 7-bits of the threshold. Total
hysteresis = 7-bits [4-bits, 000b]
R/W
8.6.38 HIGH_TH_CH4 Register (Address = 0x31) [reset = 0xFF]
HIGH_TH_CH4 is shown in Figure 74 and described in Table 49.
Return to the Summary Table.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
45
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Figure 74. HIGH_TH_CH4 Register
7
6
5
4
3
HIGH_THRESHOLD_CH4_MSB[7:0]
R/W-11111111b
2
1
0
Table 49. HIGH_TH_CH4 Register Field Descriptions
Bit
Field
Type
7-0
HIGH_THRESHOLD_CH4 R/W
_MSB[7:0]
Reset
Description
11111111b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
8.6.39 EVENT_COUNT_CH4 Register (Address = 0x32) [reset = 0x0]
EVENT_COUNT_CH4 is shown in Figure 75 and described in Table 50.
Return to the Summary Table.
Figure 75. EVENT_COUNT_CH4 Register
7
6
5
LOW_THRESHOLD_CH4_LSB[3:0]
R/W-0b
4
3
2
1
EVENT_COUNT_CH4[3:0]
R/W-0b
0
Table 50. EVENT_COUNT_CH4 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-4
LOW_THRESHOLD_CH4
_LSB[3:0]
R/W
0b
Lower 4-bits of low threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
3-0
EVENT_COUNT_CH4[3:0 R/W
]
0b
Configuration for checking 'n+1' consecutive samples above
threshold before setting event flag.
8.6.40 LOW_TH_CH4 Register (Address = 0x33) [reset = 0x0]
LOW_TH_CH4 is shown in Figure 76 and described in Table 51.
Return to the Summary Table.
Figure 76. LOW_TH_CH4 Register
7
6
5
4
3
LOW_THRESHOLD_CH4_MSB[7:0]
R/W-0b
2
1
0
Table 51. LOW_TH_CH4 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
LOW_THRESHOLD_CH4
_MSB[7:0]
R/W
0b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
8.6.41 HYSTERESIS_CH5 Register (Address = 0x34) [reset = 0xF0]
HYSTERESIS_CH5 is shown in Figure 77 and described in Table 52.
Return to the Summary Table.
Figure 77. HYSTERESIS_CH5 Register
7
46
6
5
HIGH_THRESHOLD_CH5_LSB[3:0]
R/W-1111b
4
3
Submit Documentation Feedback
2
1
HYSTERESIS_CH5[3:0]
R/W-0b
0
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Table 52. HYSTERESIS_CH5 Register Field Descriptions
Bit
Field
Reset
Description
7-4
HIGH_THRESHOLD_CH5 R/W
_LSB[3:0]
Type
1111b
Lower 4-bits of high threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
3-0
HYSTERESIS_CH5[3:0]
0b
4-bit hysteresis for high and low thresholds. This 4-bit hysteris is left
shifted 3 times and applied on the lower 7-bits of the threshold. Total
hysteresis = 7-bits [4-bits, 000b]
R/W
8.6.42 HIGH_TH_CH5 Register (Address = 0x35) [reset = 0xFF]
HIGH_TH_CH5 is shown in Figure 78 and described in Table 53.
Return to the Summary Table.
Figure 78. HIGH_TH_CH5 Register
7
6
5
4
3
HIGH_THRESHOLD_CH5_MSB[7:0]
R/W-11111111b
2
1
0
Table 53. HIGH_TH_CH5 Register Field Descriptions
Bit
Field
7-0
HIGH_THRESHOLD_CH5 R/W
_MSB[7:0]
Type
Reset
Description
11111111b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
8.6.43 EVENT_COUNT_CH5 Register (Address = 0x36) [reset = 0x0]
EVENT_COUNT_CH5 is shown in Figure 79 and described in Table 54.
Return to the Summary Table.
Figure 79. EVENT_COUNT_CH5 Register
7
6
5
LOW_THRESHOLD_CH5_LSB[3:0]
R/W-0b
4
3
2
1
EVENT_COUNT_CH5[3:0]
R/W-0b
0
Table 54. EVENT_COUNT_CH5 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-4
LOW_THRESHOLD_CH5
_LSB[3:0]
R/W
0b
Lower 4-bits of low threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
3-0
EVENT_COUNT_CH5[3:0 R/W
]
0b
Configuration for checking 'n+1' consecutive samples above
threshold before setting event flag.
8.6.44 LOW_TH_CH5 Register (Address = 0x37) [reset = 0x0]
LOW_TH_CH5 is shown in Figure 80 and described in Table 55.
Return to the Summary Table.
Figure 80. LOW_TH_CH5 Register
7
6
5
4
3
LOW_THRESHOLD_CH5_MSB[7:0]
R/W-0b
2
1
0
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
47
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Table 55. LOW_TH_CH5 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
LOW_THRESHOLD_CH5
_MSB[7:0]
R/W
0b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
8.6.45 HYSTERESIS_CH6 Register (Address = 0x38) [reset = 0xF0]
HYSTERESIS_CH6 is shown in Figure 81 and described in Table 56.
Return to the Summary Table.
Figure 81. HYSTERESIS_CH6 Register
7
6
5
HIGH_THRESHOLD_CH6_LSB[3:0]
R/W-1111b
4
3
2
1
HYSTERESIS_CH6[3:0]
R/W-0b
0
Table 56. HYSTERESIS_CH6 Register Field Descriptions
Bit
Field
7-4
3-0
Type
Reset
Description
HIGH_THRESHOLD_CH6 R/W
_LSB[3:0]
1111b
Lower 4-bits of high threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
HYSTERESIS_CH6[3:0]
0b
4-bit hysteresis for high and low thresholds. This 4-bit hysteris is left
shifted 3 times and applied on the lower 7-bits of the threshold. Total
hysteresis = 7-bits [4-bits, 000b]
R/W
8.6.46 HIGH_TH_CH6 Register (Address = 0x39) [reset = 0xFF]
HIGH_TH_CH6 is shown in Figure 82 and described in Table 57.
Return to the Summary Table.
Figure 82. HIGH_TH_CH6 Register
7
6
5
4
3
HIGH_THRESHOLD_CH6_MSB[7:0]
R/W-11111111b
2
1
0
Table 57. HIGH_TH_CH6 Register Field Descriptions
Bit
Field
7-0
HIGH_THRESHOLD_CH6 R/W
_MSB[7:0]
Type
Reset
Description
11111111b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
8.6.47 EVENT_COUNT_CH6 Register (Address = 0x3A) [reset = 0x0]
EVENT_COUNT_CH6 is shown in Figure 83 and described in Table 58.
Return to the Summary Table.
Figure 83. EVENT_COUNT_CH6 Register
7
6
5
LOW_THRESHOLD_CH6_LSB[3:0]
R/W-0b
4
3
2
1
EVENT_COUNT_CH6[3:0]
R/W-0b
0
Table 58. EVENT_COUNT_CH6 Register Field Descriptions
48
Bit
Field
Type
Reset
Description
7-4
LOW_THRESHOLD_CH6
_LSB[3:0]
R/W
0b
Lower 4-bits of low threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Table 58. EVENT_COUNT_CH6 Register Field Descriptions (continued)
Bit
Field
3-0
EVENT_COUNT_CH6[3:0 R/W
]
Type
Reset
Description
0b
Configuration for checking 'n+1' consecutive samples above
threshold before setting event flag.
8.6.48 LOW_TH_CH6 Register (Address = 0x3B) [reset = 0x0]
LOW_TH_CH6 is shown in Figure 84 and described in Table 59.
Return to the Summary Table.
Figure 84. LOW_TH_CH6 Register
7
6
5
4
3
LOW_THRESHOLD_CH6_MSB[7:0]
R/W-0b
2
1
0
Table 59. LOW_TH_CH6 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
LOW_THRESHOLD_CH6
_MSB[7:0]
R/W
0b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
8.6.49 HYSTERESIS_CH7 Register (Address = 0x3C) [reset = 0xF0]
HYSTERESIS_CH7 is shown in Figure 85 and described in Table 60.
Return to the Summary Table.
Figure 85. HYSTERESIS_CH7 Register
7
6
5
HIGH_THRESHOLD_CH7_LSB[3:0]
R/W-1111b
4
3
2
1
HYSTERESIS_CH7[3:0]
R/W-0b
0
Table 60. HYSTERESIS_CH7 Register Field Descriptions
Bit
Field
7-4
3-0
Type
Reset
Description
HIGH_THRESHOLD_CH7 R/W
_LSB[3:0]
1111b
Lower 4-bits of high threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
HYSTERESIS_CH7[3:0]
0b
4-bit hysteresis for high and low thresholds. This 4-bit hysteris is left
shifted 3 times and applied on the lower 7-bits of the threshold. Total
hysteresis = 7-bits [4-bits, 000b]
R/W
8.6.50 HIGH_TH_CH7 Register (Address = 0x3D) [reset = 0xFF]
HIGH_TH_CH7 is shown in Figure 86 and described in Table 61.
Return to the Summary Table.
Figure 86. HIGH_TH_CH7 Register
7
6
5
4
3
HIGH_THRESHOLD_CH7_MSB[7:0]
R/W-11111111b
2
1
0
Table 61. HIGH_TH_CH7 Register Field Descriptions
Bit
Field
7-0
HIGH_THRESHOLD_CH7 R/W
_MSB[7:0]
Type
Reset
Description
11111111b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
49
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
8.6.51 EVENT_COUNT_CH7 Register (Address = 0x3E) [reset = 0x0]
EVENT_COUNT_CH7 is shown in Figure 87 and described in Table 62.
Return to the Summary Table.
Figure 87. EVENT_COUNT_CH7 Register
7
6
5
LOW_THRESHOLD_CH7_LSB[3:0]
R/W-0b
4
3
2
1
EVENT_COUNT_CH7[3:0]
R/W-0b
0
Table 62. EVENT_COUNT_CH7 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-4
LOW_THRESHOLD_CH7
_LSB[3:0]
R/W
0b
Lower 4-bits of low threshold for analog input. These bits are
compared with bits 3:0 of ADC conversion result.
3-0
EVENT_COUNT_CH7[3:0 R/W
]
0b
Configuration for checking 'n+1' consecutive samples above
threshold before setting event flag.
8.6.52 LOW_TH_CH7 Register (Address = 0x3F) [reset = 0x0]
LOW_TH_CH7 is shown in Figure 88 and described in Table 63.
Return to the Summary Table.
Figure 88. LOW_TH_CH7 Register
7
6
5
4
3
LOW_THRESHOLD_CH7_MSB[7:0]
R/W-0b
2
1
0
Table 63. LOW_TH_CH7 Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
LOW_THRESHOLD_CH7
_MSB[7:0]
R/W
0b
MSB aligned high threshold for analog input. These bits are
compared with top 8 bits of ADC conversion result.
8.6.53 MAX_CH0_LSB Register (Address = 0x60) [reset = 0x0]
MAX_CH0_LSB is shown in Figure 89 and described in Table 64.
Return to the Summary Table.
Figure 89. MAX_CH0_LSB Register
7
6
5
4
3
MAX_VALUE_CH0_LSB[7:0]
R-0b
2
1
0
Table 64. MAX_CH0_LSB Register Field Descriptions
Bit
Field
Type
7-0
MAX_VALUE_CH0_LSB[7 R
:0]
Reset
Description
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.54 MAX_CH0_MSB Register (Address = 0x61) [reset = 0x0]
MAX_CH0_MSB is shown in Figure 90 and described in Table 65.
Return to the Summary Table.
50
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Figure 90. MAX_CH0_MSB Register
7
6
5
4
3
MAX_VALUE_CH0_MSB[7:0]
R-0b
2
1
0
Table 65. MAX_CH0_MSB Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
MAX_VALUE_CH0_MSB[
7:0]
R
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.55 MAX_CH1_LSB Register (Address = 0x62) [reset = 0x0]
MAX_CH1_LSB is shown in Figure 91 and described in Table 66.
Return to the Summary Table.
Figure 91. MAX_CH1_LSB Register
7
6
5
4
3
MAX_VALUE_CH1_LSB[7:0]
R-0b
2
1
0
Table 66. MAX_CH1_LSB Register Field Descriptions
Bit
Field
7-0
MAX_VALUE_CH1_LSB[7 R
:0]
Type
Reset
Description
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.56 MAX_CH1_MSB Register (Address = 0x63) [reset = 0x0]
MAX_CH1_MSB is shown in Figure 92 and described in Table 67.
Return to the Summary Table.
Figure 92. MAX_CH1_MSB Register
7
6
5
4
3
MAX_VALUE_CH1_MSB[7:0]
R-0b
2
1
0
Table 67. MAX_CH1_MSB Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
MAX_VALUE_CH1_MSB[
7:0]
R
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.57 MAX_CH2_LSB Register (Address = 0x64) [reset = 0x0]
MAX_CH2_LSB is shown in Figure 93 and described in Table 68.
Return to the Summary Table.
Figure 93. MAX_CH2_LSB Register
7
6
5
4
3
MAX_VALUE_CH2_LSB[7:0]
R-0b
2
1
0
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
51
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Table 68. MAX_CH2_LSB Register Field Descriptions
Bit
Field
7-0
MAX_VALUE_CH2_LSB[7 R
:0]
Type
Reset
Description
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.58 MAX_CH2_MSB Register (Address = 0x65) [reset = 0x0]
MAX_CH2_MSB is shown in Figure 94 and described in Table 69.
Return to the Summary Table.
Figure 94. MAX_CH2_MSB Register
7
6
5
4
3
MAX_VALUE_CH2_MSB[7:0]
R-0b
2
1
0
Table 69. MAX_CH2_MSB Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
MAX_VALUE_CH2_MSB[
7:0]
R
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.59 MAX_CH3_LSB Register (Address = 0x66) [reset = 0x0]
MAX_CH3_LSB is shown in Figure 95 and described in Table 70.
Return to the Summary Table.
Figure 95. MAX_CH3_LSB Register
7
6
5
4
3
MAX_VALUE_CH3_LSB[7:0]
R-0b
2
1
0
Table 70. MAX_CH3_LSB Register Field Descriptions
Bit
Field
7-0
MAX_VALUE_CH3_LSB[7 R
:0]
Type
Reset
Description
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.60 MAX_CH3_MSB Register (Address = 0x67) [reset = 0x0]
MAX_CH3_MSB is shown in Figure 96 and described in Table 71.
Return to the Summary Table.
Figure 96. MAX_CH3_MSB Register
7
6
5
4
3
MAX_VALUE_CH3_MSB[7:0]
R-0b
2
1
0
Table 71. MAX_CH3_MSB Register Field Descriptions
52
Bit
Field
Type
Reset
Description
7-0
MAX_VALUE_CH3_MSB[
7:0]
R
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
8.6.61 MAX_CH4_LSB Register (Address = 0x68) [reset = 0x0]
MAX_CH4_LSB is shown in Figure 97 and described in Table 72.
Return to the Summary Table.
Figure 97. MAX_CH4_LSB Register
7
6
5
4
3
MAX_VALUE_CH4_LSB[7:0]
R-0b
2
1
0
Table 72. MAX_CH4_LSB Register Field Descriptions
Bit
Field
7-0
MAX_VALUE_CH4_LSB[7 R
:0]
Type
Reset
Description
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.62 MAX_CH4_MSB Register (Address = 0x69) [reset = 0x0]
MAX_CH4_MSB is shown in Figure 98 and described in Table 73.
Return to the Summary Table.
Figure 98. MAX_CH4_MSB Register
7
6
5
4
3
MAX_VALUE_CH4_MSB[7:0]
R-0b
2
1
0
Table 73. MAX_CH4_MSB Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
MAX_VALUE_CH4_MSB[
7:0]
R
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.63 MAX_CH5_LSB Register (Address = 0x6A) [reset = 0x0]
MAX_CH5_LSB is shown in Figure 99 and described in Table 74.
Return to the Summary Table.
Figure 99. MAX_CH5_LSB Register
7
6
5
4
3
MAX_VALUE_CH5_LSB[7:0]
R-0b
2
1
0
Table 74. MAX_CH5_LSB Register Field Descriptions
Bit
Field
7-0
MAX_VALUE_CH5_LSB[7 R
:0]
Type
Reset
Description
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.64 MAX_CH5_MSB Register (Address = 0x6B) [reset = 0x0]
MAX_CH5_MSB is shown in Figure 100 and described in Table 75.
Return to the Summary Table.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
53
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Figure 100. MAX_CH5_MSB Register
7
6
5
4
3
MAX_VALUE_CH5_MSB[7:0]
R-0b
2
1
0
Table 75. MAX_CH5_MSB Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
MAX_VALUE_CH5_MSB[
7:0]
R
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.65 MAX_CH6_LSB Register (Address = 0x6C) [reset = 0x0]
MAX_CH6_LSB is shown in Figure 101 and described in Table 76.
Return to the Summary Table.
Figure 101. MAX_CH6_LSB Register
7
6
5
4
3
MAX_VALUE_CH6_LSB[7:0]
R-0b
2
1
0
Table 76. MAX_CH6_LSB Register Field Descriptions
Bit
Field
7-0
MAX_VALUE_CH6_LSB[7 R
:0]
Type
Reset
Description
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.66 MAX_CH6_MSB Register (Address = 0x6D) [reset = 0x0]
MAX_CH6_MSB is shown in Figure 102 and described in Table 77.
Return to the Summary Table.
Figure 102. MAX_CH6_MSB Register
7
6
5
4
3
MAX_VALUE_CH6_MSB[7:0]
R-0b
2
1
0
Table 77. MAX_CH6_MSB Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
MAX_VALUE_CH6_MSB[
7:0]
R
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.67 MAX_CH7_LSB Register (Address = 0x6E) [reset = 0x0]
MAX_CH7_LSB is shown in Figure 103 and described in Table 78.
Return to the Summary Table.
Figure 103. MAX_CH7_LSB Register
7
54
6
5
4
3
MAX_VALUE_CH7_LSB[7:0]
R-0b
Submit Documentation Feedback
2
1
0
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Table 78. MAX_CH7_LSB Register Field Descriptions
Bit
Field
7-0
MAX_VALUE_CH7_LSB[7 R
:0]
Type
Reset
Description
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.68 MAX_CH7_MSB Register (Address = 0x6F) [reset = 0x0]
MAX_CH7_MSB is shown in Figure 104 and described in Table 79.
Return to the Summary Table.
Figure 104. MAX_CH7_MSB Register
7
6
5
4
3
MAX_VALUE_CH7_MSB[7:0]
R-0b
2
1
0
Table 79. MAX_CH7_MSB Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
MAX_VALUE_CH7_MSB[
7:0]
R
0b
Maximum code recorded on analog input channel from the last time
this register was read. Reading the register resets the value to 0.
8.6.69 MIN_CH0_LSB Register (Address = 0x80) [reset = 0xFF]
MIN_CH0_LSB is shown in Figure 105 and described in Table 80.
Return to the Summary Table.
Figure 105. MIN_CH0_LSB Register
7
6
5
4
3
MIN_VALUE_CH0_LSB[7:0]
R-11111111b
2
1
0
Table 80. MIN_CH0_LSB Register Field Descriptions
Bit
Field
7-0
MIN_VALUE_CH0_LSB[7: R
0]
Type
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
8.6.70 MIN_CH0_MSB Register (Address = 0x81) [reset = 0xFF]
MIN_CH0_MSB is shown in Figure 106 and described in Table 81.
Return to the Summary Table.
Figure 106. MIN_CH0_MSB Register
7
6
5
4
3
MIN_VALUE_CH0_MSB[7:0]
R-11111111b
2
1
0
Table 81. MIN_CH0_MSB Register Field Descriptions
Bit
Field
7-0
MIN_VALUE_CH0_MSB[7 R
:0]
Type
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
55
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
8.6.71 MIN_CH1_LSB Register (Address = 0x82) [reset = 0xFF]
MIN_CH1_LSB is shown in Figure 107 and described in Table 82.
Return to the Summary Table.
Figure 107. MIN_CH1_LSB Register
7
6
5
4
3
MIN_VALUE_CH1_LSB[7:0]
R-11111111b
2
1
0
Table 82. MIN_CH1_LSB Register Field Descriptions
Bit
Field
7-0
MIN_VALUE_CH1_LSB[7: R
0]
Type
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
8.6.72 MIN_CH1_MSB Register (Address = 0x83) [reset = 0xFF]
MIN_CH1_MSB is shown in Figure 108 and described in Table 83.
Return to the Summary Table.
Figure 108. MIN_CH1_MSB Register
7
6
5
4
3
MIN_VALUE_CH1_MSB[7:0]
R-11111111b
2
1
0
Table 83. MIN_CH1_MSB Register Field Descriptions
Bit
Field
Type
7-0
MIN_VALUE_CH1_MSB[7 R
:0]
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
8.6.73 MIN_CH2_LSB Register (Address = 0x84) [reset = 0xFF]
MIN_CH2_LSB is shown in Figure 109 and described in Table 84.
Return to the Summary Table.
Figure 109. MIN_CH2_LSB Register
7
6
5
4
3
MIN_VALUE_CH2_LSB[7:0]
R-11111111b
2
1
0
Table 84. MIN_CH2_LSB Register Field Descriptions
Bit
Field
Type
7-0
MIN_VALUE_CH2_LSB[7: R
0]
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
8.6.74 MIN_CH2_MSB Register (Address = 0x85) [reset = 0xFF]
MIN_CH2_MSB is shown in Figure 110 and described in Table 85.
Return to the Summary Table.
56
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Figure 110. MIN_CH2_MSB Register
7
6
5
4
3
MIN_VALUE_CH2_MSB[7:0]
R-11111111b
2
1
0
Table 85. MIN_CH2_MSB Register Field Descriptions
Bit
Field
Type
7-0
MIN_VALUE_CH2_MSB[7 R
:0]
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
8.6.75 MIN_CH3_LSB Register (Address = 0x86) [reset = 0xFF]
MIN_CH3_LSB is shown in Figure 111 and described in Table 86.
Return to the Summary Table.
Figure 111. MIN_CH3_LSB Register
7
6
5
4
3
MIN_VALUE_CH3_LSB[7:0]
R-11111111b
2
1
0
Table 86. MIN_CH3_LSB Register Field Descriptions
Bit
Field
Type
7-0
MIN_VALUE_CH3_LSB[7: R
0]
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
8.6.76 MIN_CH3_MSB Register (Address = 0x87) [reset = 0xFF]
MIN_CH3_MSB is shown in Figure 112 and described in Table 87.
Return to the Summary Table.
Figure 112. MIN_CH3_MSB Register
7
6
5
4
3
MIN_VALUE_CH3_MSB[7:0]
R-11111111b
2
1
0
Table 87. MIN_CH3_MSB Register Field Descriptions
Bit
Field
7-0
MIN_VALUE_CH3_MSB[7 R
:0]
Type
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
8.6.77 MIN_CH4_LSB Register (Address = 0x88) [reset = 0xFF]
MIN_CH4_LSB is shown in Figure 113 and described in Table 88.
Return to the Summary Table.
Figure 113. MIN_CH4_LSB Register
7
6
5
4
3
MIN_VALUE_CH4_LSB[7:0]
R-11111111b
2
1
0
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
57
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Table 88. MIN_CH4_LSB Register Field Descriptions
Bit
Field
7-0
MIN_VALUE_CH4_LSB[7: R
0]
Type
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
8.6.78 MIN_CH4_MSB Register (Address = 0x89) [reset = 0xFF]
MIN_CH4_MSB is shown in Figure 114 and described in Table 89.
Return to the Summary Table.
Figure 114. MIN_CH4_MSB Register
7
6
5
4
3
MIN_VALUE_CH4_MSB[7:0]
R-11111111b
2
1
0
Table 89. MIN_CH4_MSB Register Field Descriptions
Bit
Field
7-0
MIN_VALUE_CH4_MSB[7 R
:0]
Type
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
8.6.79 MIN_CH5_LSB Register (Address = 0x8A) [reset = 0xFF]
MIN_CH5_LSB is shown in Figure 115 and described in Table 90.
Return to the Summary Table.
Figure 115. MIN_CH5_LSB Register
7
6
5
4
3
MIN_VALUE_CH5_LSB[7:0]
R-11111111b
2
1
0
Table 90. MIN_CH5_LSB Register Field Descriptions
Bit
Field
Type
7-0
MIN_VALUE_CH5_LSB[7: R
0]
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
8.6.80 MIN_CH5_MSB Register (Address = 0x8B) [reset = 0xFF]
MIN_CH5_MSB is shown in Figure 116 and described in Table 91.
Return to the Summary Table.
Figure 116. MIN_CH5_MSB Register
7
6
5
4
3
MIN_VALUE_CH5_MSB[7:0]
R-11111111b
2
1
0
Table 91. MIN_CH5_MSB Register Field Descriptions
58
Bit
Field
Type
7-0
MIN_VALUE_CH5_MSB[7 R
:0]
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
8.6.81 MIN_CH6_LSB Register (Address = 0x8C) [reset = 0xFF]
MIN_CH6_LSB is shown in Figure 117 and described in Table 92.
Return to the Summary Table.
Figure 117. MIN_CH6_LSB Register
7
6
5
4
3
MIN_VALUE_CH6_LSB[7:0]
R-11111111b
2
1
0
Table 92. MIN_CH6_LSB Register Field Descriptions
Bit
Field
7-0
MIN_VALUE_CH6_LSB[7: R
0]
Type
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
8.6.82 MIN_CH6_MSB Register (Address = 0x8D) [reset = 0xFF]
MIN_CH6_MSB is shown in Figure 118 and described in Table 93.
Return to the Summary Table.
Figure 118. MIN_CH6_MSB Register
7
6
5
4
3
MIN_VALUE_CH6_MSB[7:0]
R-11111111b
2
1
0
Table 93. MIN_CH6_MSB Register Field Descriptions
Bit
Field
Type
7-0
MIN_VALUE_CH6_MSB[7 R
:0]
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
8.6.83 MIN_CH7_LSB Register (Address = 0x8E) [reset = 0xFF]
MIN_CH7_LSB is shown in Figure 119 and described in Table 94.
Return to the Summary Table.
Figure 119. MIN_CH7_LSB Register
7
6
5
4
3
MIN_VALUE_CH7_LSB[7:0]
R-11111111b
2
1
0
Table 94. MIN_CH7_LSB Register Field Descriptions
Bit
Field
Type
7-0
MIN_VALUE_CH7_LSB[7: R
0]
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
8.6.84 MIN_CH7_MSB Register (Address = 0x8F) [reset = 0xFF]
MIN_CH7_MSB is shown in Figure 120 and described in Table 95.
Return to the Summary Table.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
59
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Figure 120. MIN_CH7_MSB Register
7
6
5
4
3
MIN_VALUE_CH7_MSB[7:0]
R-11111111b
2
1
0
Table 95. MIN_CH7_MSB Register Field Descriptions
Bit
Field
Type
7-0
MIN_VALUE_CH7_MSB[7 R
:0]
Reset
Description
11111111b
Minimum code recorded on the analog input channel from the last
time this register was read. Reading the register resets the value to
0xFF.
8.6.85 RECENT_CH0_LSB Register (Address = 0xA0) [reset = 0x0]
RECENT_CH0_LSB is shown in Figure 121 and described in Table 96.
Return to the Summary Table.
Figure 121. RECENT_CH0_LSB Register
7
6
5
4
3
LAST_VALUE_CH0_LSB[7:0]
R-0b
2
1
0
Table 96. RECENT_CH0_LSB Register Field Descriptions
Bit
Field
Type
7-0
LAST_VALUE_CH0_LSB[ R
7:0]
Reset
Description
0b
Next 8 bits of the last result for this analog input channel.
8.6.86 RECENT_CH0_MSB Register (Address = 0xA1) [reset = 0x0]
RECENT_CH0_MSB is shown in Figure 122 and described in Table 97.
Return to the Summary Table.
Figure 122. RECENT_CH0_MSB Register
7
6
5
4
3
LAST_VALUE_CH0_MSB[7:0]
R-0b
2
1
0
Table 97. RECENT_CH0_MSB Register Field Descriptions
Bit
Field
7-0
LAST_VALUE_CH0_MSB R
[7:0]
Type
Reset
Description
0b
MSB aligned first 8 bits of the last result for this analog input
channel.
8.6.87 RECENT_CH1_LSB Register (Address = 0xA2) [reset = 0x0]
RECENT_CH1_LSB is shown in Figure 123 and described in Table 98.
Return to the Summary Table.
Figure 123. RECENT_CH1_LSB Register
7
60
6
5
4
3
LAST_VALUE_CH1_LSB[7:0]
R-0b
Submit Documentation Feedback
2
1
0
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Table 98. RECENT_CH1_LSB Register Field Descriptions
Bit
Field
7-0
LAST_VALUE_CH1_LSB[ R
7:0]
Type
Reset
Description
0b
Next 8 bits of the last result for this analog input channel.
8.6.88 RECENT_CH1_MSB Register (Address = 0xA3) [reset = 0x0]
RECENT_CH1_MSB is shown in Figure 124 and described in Table 99.
Return to the Summary Table.
Figure 124. RECENT_CH1_MSB Register
7
6
5
4
3
LAST_VALUE_CH1_MSB[7:0]
R-0b
2
1
0
Table 99. RECENT_CH1_MSB Register Field Descriptions
Bit
Field
Type
7-0
LAST_VALUE_CH1_MSB R
[7:0]
Reset
Description
0b
MSB aligned first 8 bits of the last result for this analog input
channel.
8.6.89 RECENT_CH2_LSB Register (Address = 0xA4) [reset = 0x0]
RECENT_CH2_LSB is shown in Figure 125 and described in Table 100.
Return to the Summary Table.
Figure 125. RECENT_CH2_LSB Register
7
6
5
4
3
LAST_VALUE_CH2_LSB[7:0]
R-0b
2
1
0
Table 100. RECENT_CH2_LSB Register Field Descriptions
Bit
Field
7-0
LAST_VALUE_CH2_LSB[ R
7:0]
Type
Reset
Description
0b
Next 8 bits of the last result for this analog input channel.
8.6.90 RECENT_CH2_MSB Register (Address = 0xA5) [reset = 0x0]
RECENT_CH2_MSB is shown in Figure 126 and described in Table 101.
Return to the Summary Table.
Figure 126. RECENT_CH2_MSB Register
7
6
5
4
3
LAST_VALUE_CH2_MSB[7:0]
R-0b
2
1
0
Table 101. RECENT_CH2_MSB Register Field Descriptions
Bit
Field
7-0
LAST_VALUE_CH2_MSB R
[7:0]
Type
Reset
Description
0b
MSB aligned first 8 bits of the last result for this analog input
channel.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
61
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
8.6.91 RECENT_CH3_LSB Register (Address = 0xA6) [reset = 0x0]
RECENT_CH3_LSB is shown in Figure 127 and described in Table 102.
Return to the Summary Table.
Figure 127. RECENT_CH3_LSB Register
7
6
5
4
3
LAST_VALUE_CH3_LSB[7:0]
R-0b
2
1
0
Table 102. RECENT_CH3_LSB Register Field Descriptions
Bit
Field
7-0
LAST_VALUE_CH3_LSB[ R
7:0]
Type
Reset
Description
0b
Next 8 bits of the last result for this analog input channel.
8.6.92 RECENT_CH3_MSB Register (Address = 0xA7) [reset = 0x0]
RECENT_CH3_MSB is shown in Figure 128 and described in Table 103.
Return to the Summary Table.
Figure 128. RECENT_CH3_MSB Register
7
6
5
4
3
LAST_VALUE_CH3_MSB[7:0]
R-0b
2
1
0
Table 103. RECENT_CH3_MSB Register Field Descriptions
Bit
Field
7-0
LAST_VALUE_CH3_MSB R
[7:0]
Type
Reset
Description
0b
MSB aligned first 8 bits of the last result for this analog input
channel.
8.6.93 RECENT_CH4_LSB Register (Address = 0xA8) [reset = 0x0]
RECENT_CH4_LSB is shown in Figure 129 and described in Table 104.
Return to the Summary Table.
Figure 129. RECENT_CH4_LSB Register
7
6
5
4
3
LAST_VALUE_CH4_LSB[7:0]
R-0b
2
1
0
Table 104. RECENT_CH4_LSB Register Field Descriptions
Bit
Field
7-0
LAST_VALUE_CH4_LSB[ R
7:0]
Type
Reset
Description
0b
Next 8 bits of the last result for this analog input channel.
8.6.94 RECENT_CH4_MSB Register (Address = 0xA9) [reset = 0x0]
RECENT_CH4_MSB is shown in Figure 130 and described in Table 105.
Return to the Summary Table.
62
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Figure 130. RECENT_CH4_MSB Register
7
6
5
4
3
LAST_VALUE_CH4_MSB[7:0]
R-0b
2
1
0
Table 105. RECENT_CH4_MSB Register Field Descriptions
Bit
Field
Type
7-0
LAST_VALUE_CH4_MSB R
[7:0]
Reset
Description
0b
MSB aligned first 8 bits of the last result for this analog input
channel.
8.6.95 RECENT_CH5_LSB Register (Address = 0xAA) [reset = 0x0]
RECENT_CH5_LSB is shown in Figure 131 and described in Table 106.
Return to the Summary Table.
Figure 131. RECENT_CH5_LSB Register
7
6
5
4
3
LAST_VALUE_CH5_LSB[7:0]
R-0b
2
1
0
Table 106. RECENT_CH5_LSB Register Field Descriptions
Bit
Field
7-0
LAST_VALUE_CH5_LSB[ R
7:0]
Type
Reset
Description
0b
Next 8 bits of the last result for this analog input channel.
8.6.96 RECENT_CH5_MSB Register (Address = 0xAB) [reset = 0x0]
RECENT_CH5_MSB is shown in Figure 132 and described in Table 107.
Return to the Summary Table.
Figure 132. RECENT_CH5_MSB Register
7
6
5
4
3
LAST_VALUE_CH5_MSB[7:0]
R-0b
2
1
0
Table 107. RECENT_CH5_MSB Register Field Descriptions
Bit
Field
7-0
LAST_VALUE_CH5_MSB R
[7:0]
Type
Reset
Description
0b
MSB aligned first 8 bits of the last result for this analog input
channel.
8.6.97 RECENT_CH6_LSB Register (Address = 0xAC) [reset = 0x0]
RECENT_CH6_LSB is shown in Figure 133 and described in Table 108.
Return to the Summary Table.
Figure 133. RECENT_CH6_LSB Register
7
6
5
4
3
LAST_VALUE_CH6_LSB[7:0]
R-0b
2
1
0
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
63
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Table 108. RECENT_CH6_LSB Register Field Descriptions
Bit
Field
7-0
LAST_VALUE_CH6_LSB[ R
7:0]
Type
Reset
Description
0b
Next 8 bits of the last result for this analog input channel.
8.6.98 RECENT_CH6_MSB Register (Address = 0xAD) [reset = 0x0]
RECENT_CH6_MSB is shown in Figure 134 and described in Table 109.
Return to the Summary Table.
Figure 134. RECENT_CH6_MSB Register
7
6
5
4
3
LAST_VALUE_CH6_MSB[7:0]
R-0b
2
1
0
Table 109. RECENT_CH6_MSB Register Field Descriptions
Bit
Field
Type
7-0
LAST_VALUE_CH6_MSB R
[7:0]
Reset
Description
0b
MSB aligned first 8 bits of the last result for this analog input
channel.
8.6.99 RECENT_CH7_LSB Register (Address = 0xAE) [reset = 0x0]
RECENT_CH7_LSB is shown in Figure 135 and described in Table 110.
Return to the Summary Table.
Figure 135. RECENT_CH7_LSB Register
7
6
5
4
3
LAST_VALUE_CH7_LSB[7:0]
R-0b
2
1
0
Table 110. RECENT_CH7_LSB Register Field Descriptions
Bit
Field
7-0
LAST_VALUE_CH7_LSB[ R
7:0]
Type
Reset
Description
0b
Next 8 bits of the last result for this analog input channel.
8.6.100 RECENT_CH7_MSB Register (Address = 0xAF) [reset = 0x0]
RECENT_CH7_MSB is shown in Figure 136 and described in Table 111.
Return to the Summary Table.
Figure 136. RECENT_CH7_MSB Register
7
6
5
4
3
LAST_VALUE_CH7_MSB[7:0]
R-0b
2
1
0
Table 111. RECENT_CH7_MSB Register Field Descriptions
64
Bit
Field
7-0
LAST_VALUE_CH7_MSB R
[7:0]
Type
Reset
Description
0b
MSB aligned first 8 bits of the last result for this analog input
channel.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
8.6.101 GPO0_TRIG_EVENT_SEL Register (Address = 0xC3) [reset = 0x2]
GPO0_TRIG_EVENT_SEL is shown in Figure 137 and described in Table 112.
Return to the Summary Table.
Figure 137. GPO0_TRIG_EVENT_SEL Register
7
6
5
4
3
GPO0_TRIG_EVENT_SEL[7:0]
R/W-10b
2
1
0
Table 112. GPO0_TRIG_EVENT_SEL Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
GPO0_TRIG_EVENT_SE
L[7:0]
R/W
10b
Select the inputs AIN/GPIO[7:0], analog or digital, which can trigger
an event based update on GPO0.
0b = Alert flags for the AIN/GPIO corresponding to this bit do not
trigger GPO0 output.
1b = Alert flags for the AIN/GPIO corresponding to this bit trigger
GPO0 output.
8.6.102 GPO1_TRIG_EVENT_SEL Register (Address = 0xC5) [reset = 0x2]
GPO1_TRIG_EVENT_SEL is shown in Figure 138 and described in Table 113.
Return to the Summary Table.
Figure 138. GPO1_TRIG_EVENT_SEL Register
7
6
5
4
3
GPO1_TRIG_EVENT_SEL[7:0]
R/W-10b
2
1
0
Table 113. GPO1_TRIG_EVENT_SEL Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
GPO1_TRIG_EVENT_SE
L[7:0]
R/W
10b
Select the inputs AIN/GPIO[7:0], analog or digital, which can trigger
an event based update on GPO1.
0b = Alert flags for the AIN/GPIO corresponding to this bit do not
trigger GPO1 output.
1b = Alert flags for the AIN/GPIO corresponding to this bit trigger
GPO1 output.
8.6.103 GPO2_TRIG_EVENT_SEL Register (Address = 0xC7) [reset = 0x2]
GPO2_TRIG_EVENT_SEL is shown in Figure 139 and described in Table 114.
Return to the Summary Table.
Figure 139. GPO2_TRIG_EVENT_SEL Register
7
6
5
4
3
GPO2_TRIG_EVENT_SEL[7:0]
R/W-10b
2
1
0
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
65
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Table 114. GPO2_TRIG_EVENT_SEL Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
GPO2_TRIG_EVENT_SE
L[7:0]
R/W
10b
Select the inputs AIN/GPIO[7:0], analog or digital, which can trigger
an event based update on GPO2.
0b = Alert flags for the AIN/GPIO corresponding to this bit do not
trigger GPO2 output.
1b = Alert flags for the AIN/GPIO corresponding to this bit trigger
GPO2 output.
8.6.104 GPO3_TRIG_EVENT_SEL Register (Address = 0xC9) [reset = 0x2]
GPO3_TRIG_EVENT_SEL is shown in Figure 140 and described in Table 115.
Return to the Summary Table.
Figure 140. GPO3_TRIG_EVENT_SEL Register
7
6
5
4
3
2
1
0
GPO3_TRIG_EVENT_SEL[7:0]
R/W-10b
Table 115. GPO3_TRIG_EVENT_SEL Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
GPO3_TRIG_EVENT_SE
L[7:0]
R/W
10b
Select the inputs AIN/GPIO[7:0], analog or digital, which can trigger
an event based update on GPO3.
0b = Alert flags for the AIN/GPIO corresponding to this bit do not
trigger GPO3 output.
1b = Alert flags for the AIN/GPIO corresponding to this bit trigger
GPO3 output.
8.6.105 GPO4_TRIG_EVENT_SEL Register (Address = 0xCB) [reset = 0x2]
GPO4_TRIG_EVENT_SEL is shown in Figure 141 and described in Table 116.
Return to the Summary Table.
Figure 141. GPO4_TRIG_EVENT_SEL Register
7
6
5
4
3
GPO4_TRIG_EVENT_SEL[7:0]
R/W-10b
2
1
0
Table 116. GPO4_TRIG_EVENT_SEL Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
GPO4_TRIG_EVENT_SE
L[7:0]
R/W
10b
Select the inputs AIN/GPIO[7:0], analog or digital, which can trigger
an event based update on GPO4.
0b = Alert flags for the AIN/GPIO corresponding to this bit do not
trigger GPO4 output.
1b = Alert flags for the AIN/GPIO corresponding to this bit trigger
GPO4 output.
8.6.106 GPO5_TRIG_EVENT_SEL Register (Address = 0xCD) [reset = 0x2]
GPO5_TRIG_EVENT_SEL is shown in Figure 142 and described in Table 117.
Return to the Summary Table.
66
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Figure 142. GPO5_TRIG_EVENT_SEL Register
7
6
5
4
3
GPO0_TRIG_EVENT_SEL[7:0]
R/W-10b
2
1
0
Table 117. GPO5_TRIG_EVENT_SEL Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
GPO0_TRIG_EVENT_SE
L[7:0]
R/W
10b
Select the inputs AIN/GPIO[7:0], analog or digital, which can trigger
an event based update on GPO5.
0b = Alert flags for the AIN/GPIO corresponding to this bit do not
trigger GPO5 output.
1b = Alert flags for the AIN/GPIO corresponding to this bit trigger
GPO5 output.
8.6.107 GPO6_TRIG_EVENT_SEL Register (Address = 0xCF) [reset = 0x2]
GPO6_TRIG_EVENT_SEL is shown in Figure 143 and described in Table 118.
Return to the Summary Table.
Figure 143. GPO6_TRIG_EVENT_SEL Register
7
6
5
4
3
GPO6_TRIG_EVENT_SEL[7:0]
R/W-10b
2
1
0
Table 118. GPO6_TRIG_EVENT_SEL Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
GPO6_TRIG_EVENT_SE
L[7:0]
R/W
10b
Select the inputs AIN/GPIO[7:0], analog or digital, which can trigger
an event based update on GPO6.
0b = Alert flags for the AIN/GPIO corresponding to this bit do not
trigger GPO6 output.
1b = Alert flags for the AIN/GPIO corresponding to this bit trigger
GPO6 output.
8.6.108 GPO7_TRIG_EVENT_SEL Register (Address = 0xD1) [reset = 0x2]
GPO7_TRIG_EVENT_SEL is shown in Figure 144 and described in Table 119.
Return to the Summary Table.
Figure 144. GPO7_TRIG_EVENT_SEL Register
7
6
5
4
3
GPO7_TRIG_EVENT_SEL[7:0]
R/W-10b
2
1
0
Table 119. GPO7_TRIG_EVENT_SEL Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
GPO7_TRIG_EVENT_SE
L[7:0]
R/W
10b
Select the inputs AIN/GPIO[7:0], analog or digital, which can trigger
an event based update on GPO7.
0b = Alert flags for the AIN/GPIO corresponding to this bit do not
trigger GPO7 output.
1b = Alert flags for the AIN/GPIO corresponding to this bit trigger
GPO7 output.
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
67
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
8.6.109 GPO_TRIGGER_CFG Register (Address = 0xE9) [reset = 0x0]
GPO_TRIGGER_CFG is shown in Figure 145 and described in Table 120.
Return to the Summary Table.
Figure 145. GPO_TRIGGER_CFG Register
7
6
5
4
3
GPO_TRIGGER_UPDATE_EN[7:0]
R/W-0b
2
1
0
Table 120. GPO_TRIGGER_CFG Register Field Descriptions
Bit
Field
Type
Reset
Description
7-0
GPO_TRIGGER_UPDAT
E_EN[7:0]
R/W
0b
Update digital outputs GPO[7:0] when corresponding trigger is set.
0b = Digital output is not updated in response to alert flags.
1b = Digital output is updated when corresponding alert flags are set.
Configure GPOx_TRIG_EVENT_SEL register to select which alert
flags can trigger an update on the desired GPO.
8.6.110 GPO_VALUE_TRIG Register (Address = 0xEB) [reset = 0x0]
GPO_VALUE_TRIG is shown in Figure 146 and described in Table 121.
Return to the Summary Table.
Figure 146. GPO_VALUE_TRIG Register
7
6
5
4
3
GPO_VALUE_ON_TRIGGER[7:0]
R/W-0b
2
1
0
Table 121. GPO_VALUE_TRIG Register Field Descriptions
Bit
Field
Type
7-0
GPO_VALUE_ON_TRIGG R/W
ER[7:0]
Reset
Description
0b
Value to be set on digital outputs GPO[7:0] when corresponding
trigger occurs. GPO update on alert flags must be enabled in
corresponding bit in GPO_TRIGGER_CFG register.
0b = Digital output set to logic 0.
1b = Digital output set to logic 1.
68
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
9 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
9.1 Application Information
The following sections give example circuits and suggestions for using the ADS7138 in various applications.
9.2 Typical Applications
9.2.1 Mixed-Channel Configuration
AVDD (VREF)
Digital Output (open-drain)
Digital Output (push-pull)
Analog Input
Analog Input
Analog Input
Analog Input
I2C
Controller
Device
Digital Input
Digital Input
Figure 147. DAQ Circuit: Single-Supply DAQ
9.2.1.1 Design Requirements
The goal of this application is to configure some channels of the ADS7138 as digital inputs, open-drain digital
outputs, and push-pull digital outputs.
9.2.1.2 Detailed Design Procedure
The ADS7138 can support GPIO functionality at each input pin. Any analog input pin can be independently
configured as a digital input, a digital open-drain output, or a digital push-pull output though the PIN_CFG and
GPIO_CFG registers; see Table 4.
9.2.1.2.1 Digital Input
The digital input functionality can be used to monitor a signal within the system. Figure 148 illustrates that the
state of the digital input can be read from the GPI_VALUE register.
ADC
From input device
AVDD
GPIx
SW
GPIx
Figure 148. Digital Input
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
69
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
Typical Applications (continued)
9.2.1.2.2 Digital Open-Drain Output
The channels of the ADS7138 can be configured as digital open-drain outputs supporting an output voltage up to
5.5 V. An open-drain output, as shown in Figure 149, consists of an internal FET (Q) connected to ground. The
output is idle when not driven by the device, which means Q is off and the pull-up resistor, RPULL_UP, connects
the GPOx node to the desired output voltage. The output voltage can range anywhere up to 5.5 V, depending on
the external voltage that the GPIOx is pulled up to. When the device is driving the output, Q turns on, thus
connecting the pull-up resistor to ground and bringing the node voltage at GPOx low.
VPULL_UP
Receiving Device
ADC
RPULL_UP
GPOx
ILOAD
Q
Figure 149. Digital Open-Drain Output
The minimum value of the pullup resistor, as calculated in Equation 3, is given by the ratio of VPULL_UP and the
maximum current supported by the device digital output (5 mA).
RMIN = (VPULL_UP / 5 mA)
(3)
The maximum value of the pullup resistor, as calculated in Equation 4, depends on the minimum input current
requirement, ILOAD, of the receiving device driven by this GPIO.
RMAX = (VPULL_UP / ILOAD)
(4)
Select RPULL_UP such that RMIN < RPULL_UP < RMAX.
9.2.1.3 Application Curve
60000
Frequency
45000
39581
30000
25955
15000
0
2048
2049
Output Code
C001
Standard deviation = 0.49 LSB
Figure 150. DC Input Histogram
70
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
Typical Applications (continued)
9.2.2 Digital Push-Pull Output
The channels of the ADS7138 can be configured as digital push-pull outputs supporting an output voltage up to
AVDD. As shown in Figure 151, a push-pull output consists of two mirrored opposite bipolar transistors, Q1 and
Q2. The device can both source and sink current because only one transistor is on at a time (either Q2 is on and
pulls the output low, or Q1 is on and sets the output high). A push-pull configuration always drives the line
opposed to an open-drain output where the line is left floating.
ADC
AVDD
Q1
GPOx
Digital
output
Q2
Figure 151. Digital Push-Pull Output
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
71
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
10 Power Supply Recommendations
10.1 AVDD and DVDD Supply Recommendations
The ADS7138 has two separate power supplies: AVDD and DVDD. The device operates on AVDD; DVDD is
used for the interface circuits. For supplies greater than 2.35 V, AVDD and DVDD can be shorted externally if
single-supply operation is desired. The AVDD supply also defines the full-scale input range of the device.
Decouple the AVDD and DVDD pins individually, as shown in Figure 152, with 1-µF ceramic decoupling
capacitors. The minimum capacitor value required for AVDD and DVDD is 200 nF and 20 nF, respectively. If
both supplies are powered from the same source, a minimum capacitor value of 220 nF is required for
decoupling.
Connect a 1-µF decoupling capacitor between the DECAP and GND pins for the internal power supply.
AVDD
AVDD
1 PF
DECAP
1 PF
GND
GND
1 PF
DVDD
DVDD
Figure 152. Power-Supply Decoupling
72
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
ADS7138
www.ti.com
SBAS976A – MAY 2019 – REVISED MAY 2020
11 Layout
11.1 Layout Guidelines
Figure 153 shows a board layout example for the ADS7138. Avoid crossing digital lines with the analog signal
path and keep the analog input signals and the AVDD supply away from noise sources.
Use 1-µF ceramic bypass capacitors in close proximity to the analog (AVDD) and digital (DVDD) power-supply
pins. Avoid placing vias between the AVDD and DVDD pins and the bypass capacitors. Connect the GND pin to
the ground plane using short, low-impedance paths. The AVDD supply voltage also functions as the reference
voltage for the ADS7138. Place the decoupling capacitor for AVDD close to the device AVDD and GND pins and
connect the decoupling capacitor to the device pins with thick copper tracks.
DVDD
GND
ALERT
ADDR
11.2 Layout Example
SCL
DECAP
SDA
AVDD
AIN/GPIO
Figure 153. Example Layout
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
73
ADS7138
SBAS976A – MAY 2019 – REVISED MAY 2020
www.ti.com
12 Device and Documentation Support
12.1 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper
right corner, click on Alert me to register and receive a weekly digest of any product information that has
changed. For change details, review the revision history included in any revised document.
12.2 Support Resources
TI E2E™ support forums are an engineer's go-to source for fast, verified answers and design help — straight
from the experts. Search existing answers or ask your own question to get the quick design help you need.
Linked content is provided "AS IS" by the respective contributors. They do not constitute TI specifications and do
not necessarily reflect TI's views; see TI's Terms of Use.
12.3 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
12.4 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
12.5 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
13 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
74
Submit Documentation Feedback
Copyright © 2019–2020, Texas Instruments Incorporated
Product Folder Links: ADS7138
PACKAGE OPTION ADDENDUM
www.ti.com
19-Aug-2021
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
ADS7138IRTER
ACTIVE
WQFN
RTE
16
3000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
7138
ADS7138IRTET
ACTIVE
WQFN
RTE
16
250
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
7138
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of