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DAC128S085
SNAS407H – AUGUST 2007 – REVISED APRIL 2015
DAC128S085 12-Bit Micro-Power OCTAL Digital-to-Analog Converter With Rail-to-Rail
Outputs
1 Features
3 Description
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The DAC128S085 is a full-featured, general-purpose
OCTAL
12-bit
voltage-output
digital-to-analog
converter (DAC) that can operate from a single 2.7-V
to 5.5-V supply and consumes 1.95 mW at 3 V and
4.85 mW at 5 V. The DAC128S085 is packaged in a
16-lead WQFN package and a 16-lead TSSOP
package. The WQFN package makes the
DAC128S085 the smallest OCTAL DAC in its class.
The on-chip output amplifiers allow rail-to-rail output
swing, and the 3-wire serial interface operates at
clock rates up to 40 MHz over the entire supply
voltage range. Competitive devices are limited to 25MHz clock rates at supply voltages in the 2.7-V to
3.6-V range. The serial interface is compatible with
standard SPI™, QSPI, MICROWIRE, and DSP
interfaces. The DAC128S085 also offers daisy-chain
operation, where an unlimited number of
DAC128S085s can be updated simultaneously using
a single serial interface.
1
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Ensured Monotonicity
Low Power Operation
Rail-to-Rail Voltage Output
Daisy-Chain Capability
Power-on Reset to 0 V
Simultaneous Output Updating
Individual Channel Power-Down Capability
Wide Power Supply Range (2.7 V to 5.5 V)
Dual Reference Voltages With Range of 0.5 V to
VA
Operating Temperature Range of −40°C to 125°C
Smallest Package in the Industry
Resolution 12 Bits
INL ±8 LSB (Maximum)
DNL 0.75 / −0.4 LSB (Maximum)
Settling Time 8.5 μs (Maximum)
Zero Code Error 15 mV (Maximum)
Full-Scale Error −0.75 %FSR (Maximum)
Supply Power
– 1.95 mW (3 V) / 4.85 mW (5 V) Typical
– Power Down 0.3 μW (3 V) / 1 μW (5 V) Typical
There are two references for the DAC128S085. One
reference input serves channels A through D, while
the other reference serves channels E through H.
Each reference can be set independently between
0.5 V and VA, providing the widest possible output
dynamic range. The DAC128S085 has a 16-bit input
shift register that controls the mode of operation, the
power-down condition, and the register/output value
of the DAC channels. All eight DAC outputs can be
updated simultaneously or individually.
2 Applications
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Battery-Powered Instruments
Digital Gain and Offset Adjustment
Programmable Voltage and Current Sources
Programmable Attenuators
Voltage Reference for ADCs
Sensor Supply Voltage
Range Detectors
Device Information(1)
PART NUMBER
DAC128S085
PACKAGE
BODY SIZE (NOM)
TSSOP (16)
5.00 mm × 4.4 mm
WQFN (16)
4.00 mm × 4.00 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Simplified Schematic
Wide supply range
VDD
2 Individual
References
independent of
VDD
VREF2
VREF1
OUTA
OUTB
OUTC
4-wire SPI
Digital I/O
tolerant of
Master to DAC
rail potential
mismatch
CONTROLLER
MCU
(Master)
OUTD
OUTE
OUTF
OUTG
OUTH
GND
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.
DAC128S085
SNAS407H – AUGUST 2007 – REVISED APRIL 2015
www.ti.com
Table of Contents
1
2
3
4
5
6
7
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Description (continued).........................................
Pin Configuration and Functions .........................
Specifications.........................................................
7.1
7.2
7.3
7.4
7.5
7.6
7.7
8
1
1
1
2
3
4
5
Absolute Maximum Ratings ...................................... 5
ESD Ratings ............................................................ 5
Recommended Operating Conditions....................... 5
Thermal Information .................................................. 6
Electrical Characteristics........................................... 6
AC and Timing Characteristics ................................. 9
Typical Characteristics ............................................ 11
Detailed Description ............................................ 15
8.1 Overview ................................................................. 15
8.2 Functional Block Diagram ....................................... 15
8.3 Feature Description................................................. 16
8.4 Device Functional Modes........................................ 20
8.5 Programming........................................................... 21
9
Application and Implementation ........................ 22
9.1 Application Information............................................ 22
9.2 Typical Application ................................................. 22
10 Power Supply Recommendations ..................... 23
11 Layout................................................................... 23
11.1 Layout Guidelines ................................................. 23
11.2 Layout Example .................................................... 24
12 Device and Documentation Support ................. 25
12.1
12.2
12.3
12.4
12.5
Device Support......................................................
Documentation Support ........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
25
26
26
26
26
13 Mechanical, Packaging, and Orderable
Information ........................................................... 26
4 Revision History
Changes from Revision G (January 2015) to Revision H
Page
•
Switched WQFN and TSSOP pinouts to their correct titles .................................................................................................. 4
•
Re-drew TSSOP pinout as a square to better reflect mechanical packaging drawings ........................................................ 4
Changes from Revision F (March 2013) to Revision G
•
Added Pin Configuration and Functions section, ESD Ratings table, Feature Description section, Device Functional
Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device
and Documentation Support section, and Mechanical, Packaging, and Orderable Information section .............................. 1
Changes from Revision E (March 2013) to Revision F
•
2
Page
Page
Changed layout of National Data Sheet to TI format ........................................................................................................... 23
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5 Description (continued)
A power-on reset circuit ensures that the DAC outputs power up to zero volts and remain there until there is a
valid write to the device. The power-down feature of the DAC128S085 allows each DAC to be independently
powered with three different termination options. With all the DAC channels powered down, power consumption
reduces to less than 0.3 µW at 3 V and less than 1 µW at 5 V. The low power consumption and small packages
of the DAC128S085 make it an excellent choice for use in battery-operated equipment.
The DAC128S085 is one of a family of pin-compatible DACs, including the 8-bit DAC088S085 and the 10-bit
DAC108S085. All three parts are offered with the same pinout, allowing system designers to select a resolution
appropriate for their application without redesigning their printed circuit board. The DAC128S085 operates over
the extended industrial temperature range of −40°C to 125°C.
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6 Pin Configuration and Functions
VOUTB
SYNC
SCLK
DIN
PW Package
16-Pin TSSOP
(Top View)
13
14
16
VOUTA
15
DOUT
RGH Package
16-Pin WQFN
(Top View)
1
2
12
VOUTE
11
VOUTF
DAC128S085
9
5
6
7
8
VREF2
GND
4
VA
VOUTD
10
3
VREF1
VOUTC
VOUTG
VOUTH
D IN
1
16
SCLK
DOUT
2
15
SYNC
VOUTA
3
14
VOUTE
VOUTB
4
13
VOUTF
VOUTC
5
12
VOUTG
VOUTD
6
11
VOUTH
VA
7
10
GND
VREF1
8
9
VREF2
DAC128S085
Pin Functions
PIN
NAME
4
TSSOP NO. WQFN NO.
TYPE
DESCRIPTION
Serial Data Input. Data is clocked into the 16-bit shift register on the falling
edges of SCLK after the fall of SYNC.
DIN
1
15
Digital Input
DOUT
2
16
Digital
Output
Serial Data Output. DOUT is utilized in daisy chain operation and is connected
directly to a DIN pin on another DAC128S085. Data is not available at DOUT
unless SYNC remains low for more than 16 SCLK cycles.
GND
10
8
Ground
Ground reference for all on-chip circuitry.
SCLK
16
14
Digital Input
Frame Synchronization Input. When this pin goes low, data is written into the
DAC's input shift register on the falling edges of SCLK. After the 16th falling
Digital Input edge of SCLK, a rising edge of SYNC causes the DAC to be updated. If
SYNC is brought high before the 15th falling edge of SCLK, the rising edge of
SYNC acts as an interrupt and the write sequence is ignored by the DAC.
Serial Clock Input. Data is clocked into the input shift register on the falling
edges of this pin.
SYNC
15
13
VA
7
5
Supply
Power supply input. Must be decoupled to GND.
Channel A Analog Output Voltage.
VOUTA
3
1
Analog
Output
VOUTB
4
2
Analog
Output
Channel B Analog Output Voltage.
VOUTC
5
3
Analog
Output
Channel C Analog Output Voltage.
VOUTD
6
4
Analog
Output
Channel D Analog Output Voltage.
VOUTE
14
12
Analog
Output
Channel E Analog Output Voltage.
VOUTF
13
11
Analog
Output
Channel F Analog Output Voltage.
VOUTG
12
10
Analog
Output
Channel G Analog Output Voltage.
VOUTH
11
9
Analog
Output
Channel H Analog Output Voltage.
VREF1
8
6
Analog
Input
Unbuffered reference voltage shared by Channels A, B, C, and D. Must be
decoupled to GND.
VREF2
9
7
Analog
Input
Unbuffered reference voltage shared by Channels E, F, G, and H. Must be
decoupled to GND.
PAD
(WQFN only)
—
17
Ground
Exposed die attach pad can be connected to ground or left floating. Soldering
the pad to the PCB offers optimal thermal performance and enhances
package self-alignment during reflow.
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7 Specifications
7.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1) (2)
MIN
Supply Voltage, VA
−0.3
Voltage on any Input Pin
MAX
UNIT
6.5
V
6.5
V
Input Current at Any Pin (3)
10
mA
Package Input Current (3)
30
Power Consumption at TA = 25°C
See
Junction Temperature
−65
Storage Temperature, Tstg
(1)
(2)
(3)
(4)
mA
(4)
150
°C
150
°C
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Recomended Operating Ratings indicate
conditions for which the device is functional, but do not specify specific performance limits. For ensured specifications and test
conditions, see Electrical Characteristics. The ensured specifications apply only for the test conditions listed. Some performance
characteristics may degrade when the device is not operated under the listed test conditions. Operation of the device beyond the
Absolute Maximum Ratings is not recommended.
All voltages are measured with respect to GND = 0 V, unless otherwise specified.
When the input voltage at any pin exceeds 5.5 V or is less than GND, the current at that pin should be limited to 10 mA. The 30-mA
maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 10
mA to three.
The absolute maximum junction temperature (TJmax) for this device is 150°C. The maximum allowable power dissipation is dictated by
TJmax, the junction-to-ambient thermal resistance (RθJA), and the ambient temperature (TA), and can be calculated using the formula
PDMAX = (TJmax − TA) / RθJA. The values for maximum power dissipation will be reached only when the device is operated in a severe
fault condition (for example, when input or output pins are driven beyond the operating ratings, or the power supply polarity is reversed).
Such conditions should always be avoided.
7.2 ESD Ratings
VALUE
V(ESD)
(1)
(2)
Electrostatic discharge
Human body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1)
±2500
Charged-device model (CDM), per JEDEC specification JESD22C101 (2)
±1000
Machine Model
±250
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)
MIN
Operating Temperature Range
MAX
UNIT
−40 ≤ TA ≤
+125
°C
Supply Voltage, VA
2.7
5.5
V
Reference Voltage, VREF1,2
0.5
VA
V
Digital Input Voltage (1)
0.0
5.5
V
0
1500
Output Load
SCLK Frequency
(1)
40
pF
MHz
The inputs are protected as shown below. Input voltage magnitudes up to 5.5 V, regardless of VA, will not cause errors in the conversion
result. For example, if VA is 3 V, the digital input pins can be driven with a 5-V logic device.
I/O
TO INTERNAL
CIRCUITRY
GND
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7.4 Thermal Information
DAC128S085
THERMAL METRIC (1)
PW (TSSOP)
RGH (WQFN)
16 PINS
16 PINS
RθJA
Junction-to-ambient thermal resistance
98
34
RθJA
Junction-to-ambient thermal resistance
31
25
RθJA
Junction-to-ambient thermal resistance
43
11
φJT
Junction-to-top characterization parameter
2
0.2
φJB
Junction-to-board characterization parameter
43
11
(1)
UNIT
°C/W
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
7.5 Electrical Characteristics
The following specifications apply for VA = 2.7 V to 5.5 V, VREF1 = VREF2 = VA, CL = 200 pF to GND, fSCLK = 30 MHz, input
code range 48 to 4047. All limits are at TA = 25°C, unless otherwise specified.
PARAMETER
TEST CONDITIONS
MIN (1)
TYP
MAX (1)
UNIT
STATIC PERFORMANCE
INL
Resolution
TMIN ≤ TA ≤ TMAX
12
Monotonicity
TMIN ≤ TA ≤ TMAX
12
Integral Non-Linearity
Bits
Bits
±2
TMIN ≤ TA ≤ TMAX
±8
0.15
DNL
Differential Non-Linearity
TMIN ≤ TA ≤ TMAX
ZE
Zero Code Error
FSE
Full-Scale Error
GE
Gain Error
ZCED
Zero Code Error Drift
TC GE
Gain Error Tempco
LSB
0.75
−0.09
TMIN ≤ TA ≤ TMAX
LSB
LSB
−0.4
IOUT = 0
+5
TMIN ≤ TA ≤ TMAX
15
−0.1%
IOUT = 0
TMIN ≤ TA ≤ TMAX
−0.75%
−0.2%
TMIN ≤ TA ≤ TMAX
−1 %
mV
FSR
FSR
−20
µV/°C
−1
ppm/°C
OUTPUT CHARACTERISTICS
IOZ
ZCO
Output Voltage Range
TMIN ≤ TA ≤ TMAX
High-Impedance Output
Leakage Current (2)
TMIN ≤ TA ≤ TMAX
Zero Code Output
0
(1)
(2)
6
Full Scale Output
V
±1
µA
VA = 3 V, IOUT = 200 µA
10
mV
VA = 3 V, IOUT = 1 mA
45
mV
8
mV
34
mV
VA = 5 V, IOUT = 200 µA
VA = 5 V, IOUT = 1 mA
FSO
VREF1,2
VA = 3 V, IOUT = 200 µA
2.984
V
VA = 3 V, IOUT = 1 mA
2.933
V
VA = 5 V, IOUT = 200 µA
4.987
V
VA = 5 V, IOUT = 1 mA
4.955
V
Test limits are ensured to TI's AOQL (Average Outgoing Quality Level).
This parameter is ensured by design and/or characterization and is not tested in production.
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Electrical Characteristics (continued)
The following specifications apply for VA = 2.7 V to 5.5 V, VREF1 = VREF2 = VA, CL = 200 pF to GND, fSCLK = 30 MHz, input
code range 48 to 4047. All limits are at TA = 25°C, unless otherwise specified.
PARAMETER
Output Short Circuit Current
(source) (3)
IOS
Output Short Circuit Current
(sink) (3)
IOS
TEST CONDITIONS
MIN (1)
TYP
CL
Maximum Load Capacitance
ZOUT
DC Output Impedance
UNIT
VA = 3 V, VOUT = 0 V,
Input Code = FFFh
−50
mA
VA = 5 V, VOUT = 0 V,
Input Code = FFFh
−60
mA
VA = 3 V, VOUT = 3 V,
Input Code = 000h
50
mA
VA = 5 V, VOUT = 5 V,
Input Code = 000h
70
mA
TA = 105°C
Continuous Output Current per TMIN ≤ TA ≤ TMAX
channel (2)
TA = 125°C
TMIN ≤ TA ≤ TMAX
IO
MAX (1)
10
mA
6.5
mA
RL = ∞
1500
pF
RL = 2 kΩ
1500
pF
8
Ω
REFERENCE INPUT
CHARACTERISTICS
Input Range Minimum
VREF1,2
Input Range Maximum
0.5
TMIN ≤ TA ≤ TMAX
V
2.7
TMIN ≤ TA ≤ TMAX
VA
Input Impedance
30
V
kΩ
LOGIC INPUT CHARACTERISTICS
IIN
Input Current (2)
TMIN ≤ TA ≤ TMAX
±1
VA = 2.7 V to 3.6 V
VIL
Input Low Voltage
µA
1
TMIN ≤ TA ≤ TMAX
0.6
VA = 4.5 V to 5.5 V
1.1
0.8
VA = 2.7 V to 3.6 V
VIH
Input High Voltage
TMIN ≤ TA ≤ TMAX
(3)
Input Capacitance (2)
TMIN ≤ TA ≤ TMAX
V
V
2.1
VA = 4.5 V to 5.5 V
TMIN ≤ TA ≤ TMAX
CIN
1.4
V
2
V
2.4
3
pF
This parameter does not represent a condition which the DAC can sustain continuously. See the continuous output current specification
for the maximum DAC output current per channel.
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Electrical Characteristics (continued)
The following specifications apply for VA = 2.7 V to 5.5 V, VREF1 = VREF2 = VA, CL = 200 pF to GND, fSCLK = 30 MHz, input
code range 48 to 4047. All limits are at TA = 25°C, unless otherwise specified.
PARAMETER
TEST CONDITIONS
MIN (1)
TYP
MAX (1)
UNIT
POWER REQUIREMENTS
VA
Supply Voltage Minimum
TMIN ≤ TA ≤ TMAX
Supply Voltage Maximum
TMIN ≤ TA ≤ TMAX
2.7
VA = 2.7 V to
3.6 V
Normal Supply Current for
supply pin VA
fSCLK = 30 MHz,
output unloaded
V
5.5
460
µA
TMIN ≤ TA ≤
TMAX
VA = 4.5 V to
5.5 V
V
560
650
µA
830
IN
VA = 2.7 V to
3.6 V
Normal Supply Current for
VREF1 or VREF2
fSCLK = 30 MHz,
output unloaded
95
µA
TMIN ≤ TA ≤
TMAX
VA = 4.5 V to
5.5 V
130
160
µA
220
Static Supply Current for
supply pin VA
fSCLK = 0,
output unloaded
Static Supply Current for
VREF1 or VREF2
fSCLK = 0,
output unloaded
IST
fSCLK = 30 MHz,
SYNC = VA and
DIN = 0V after PD
mode loaded
IPD
VA = 2.7 V to
3.6 V
370
µA
VA = 4.5 V to
5.5 V
440
µA
VA = 2.7 V to
3.6 V
95
µA
VA = 4.5 V to
5.5 V
160
µA
VA = 2.7 V to
3.6 V
0.2
VA = 4.5 V to
5.5 V
0.5
µA
TMIN ≤ TA ≤
TMAX
Total Power Down Supply
Current for all PD Modes
VA = 2.7 V to
3.6 V
(2)
fSCLK = 0, SYNC =
VA and DIN = 0V
after PD mode
loaded
3
0.1
µA
TMIN ≤ TA ≤
TMAX
VA = 4.5 V to
5.5 V
1
0.2
µA
TMIN ≤ TA ≤
TMAX
VA = 2.7 V to
3.6 V
fSCLK = 30 MHz
output unloaded
PN
Total Power Consumption
(output unloaded)
8
2
1.95
mW
TMIN ≤ TA ≤
TMAX
VA = 4.5 V to
5.5 V
3
4.85
mW
TMIN ≤ TA ≤
TMAX
fSCLK = 0
output unloaded
µA
1.5
7
VA = 2.7 V to
3.6 V
1.68
mW
VA = 4.5 V to
5.5 V
3.80
mW
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Electrical Characteristics (continued)
The following specifications apply for VA = 2.7 V to 5.5 V, VREF1 = VREF2 = VA, CL = 200 pF to GND, fSCLK = 30 MHz, input
code range 48 to 4047. All limits are at TA = 25°C, unless otherwise specified.
PARAMETER
TEST CONDITIONS
MIN (1)
VA = 2.7 V to
3.6 V
fSCLK = 30 MHz,
SYNC = VA and
DIN = 0V after PD
mode loaded
fSCLK = 0, SYNC =
VA and DIN = 0V
after PD mode
loaded
UNIT
µW
TMIN ≤ TA ≤
TMAX
5.4
VA = 4.5V to
5.5V
2.5
µW
16.5
VA = 2.7 V to
3.6 V
(2)
MAX (1)
0.6
TMIN ≤ TA ≤
TMAX
Total Power Consumption in
all PD Modes,
PPD
TYP
0.3
µW
TMIN ≤ TA ≤
TMAX
3.6
VA = 4.5 V to
5.5 V
1
µW
TMIN ≤ TA ≤
TMAX
11
7.6 AC and Timing Characteristics
The following specifications apply for VA = 2.7 V to 5.5 V, VREF1,2 = VA, CL = 200 pF to GND, fSCLK = 30 MHz, input code range
48 to 4047. All limits are at TA = 25°C, unless otherwise specified.
MIN (1)
fSCLK
SCLK Frequency
Output Voltage Settling Time
ts
(2)
NOM
40
TMIN ≤ TA ≤ TMAX
30
400h to C00h code change
RL = 2 kΩ, CL = 200 pF
6
TMIN ≤ TA ≤ TMAX
SR
Output Slew Rate
GI
Glitch Impulse
DF
DC
MAX (1)
UNIT
MHz
µs
8.5
1
V/µs
40
nV-sec
Digital Feedthrough
0.5
nV-sec
Digital Crosstalk
0.5
nV-sec
1
nV-sec
Code change from 800h to 7FFh
CROSS DAC-to-DAC Crosstalk
MBW
Multiplying Bandwidth
VREF1,2 = 2.5 V ± 2 Vpp
360
kHz
THD+N
Total Harmonic Distortion Plus
Noise
VREF1,2 = 2.5 V ± 0.5 Vpp
100 Hz < fIN < 20 kHz
−80
dB
ONSD
Output Noise Spectral Density
DAC Code = 800 h, 10 kHz
40
nV/sqrt (Hz)
ON
Output Noise
BW = 30 kHz
14
µV
VA = 3 V
3
µsec
VA = 5 V
20
µsec
tWU
Wake-Up Time
25
1/fSCLK
SCLK Cycle Time. See Figure 1
tCH
SCLK High time. See Figure 1
tCL
SCLK Low Time. See Figure 1
TMIN ≤ TA ≤ TMAX
10
tSS
SYNC Set-up Time prior to
SCLK Falling Edge. See Figure 1 TMIN ≤ TA ≤ TMAX
10
(1)
(2)
TMIN ≤ TA ≤ TMAX
33
TMIN ≤ TA ≤ TMAX
10
ns
7
ns
7
3
ns
1 / fSCLK - 3
ns
Test limits are ensured to TI's AOQL (Average Outgoing Quality Level).
This parameter is ensured by design and/or characterization and is not tested in production.
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AC and Timing Characteristics (continued)
The following specifications apply for VA = 2.7 V to 5.5 V, VREF1,2 = VA, CL = 200 pF to GND, fSCLK = 30 MHz, input code range
48 to 4047. All limits are at TA = 25°C, unless otherwise specified.
MIN (1)
MAX (1)
NOM
1
tDS
Data Set-Up Time prior to SCLK
Falling Edge. See Figure 1
TMIN ≤ TA ≤ TMAX
2.5
tDH
Data Hold Time after SCLK
Falling Edge. See Figure 1
TMIN ≤ TA ≤ TMAX
2.5
tSH
SYNC Hold Time after the 16th
falling edge of SCLK. See
Figure 1
TMIN ≤ TA ≤ TMAX
3
tSYNC
SYNC High Time. See Figure 1
ns
1
0
ns
1 / fSCLK - 3
ns
5
TMIN ≤ TA ≤ TMAX
UNIT
ns
15
|
|
1 / fSCLK
SCLK
1
tSYNC
2
15
tCL
tSS
16
1
2
15
16
tCH
|
SYNC
|
tSH
DB15
DB0
| |
DIN1
| |
tDH
DB15
DB0
tDS
| |
tDH
DIN2/DOUT1
|
DB15
DB0
tDS
Figure 1. Serial Timing Diagram
10
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7.7 Typical Characteristics
VA = 2.7 V to 5.5 V, VREF1,2 = VA, fSCLK = 30 MHz, TA = 25°C, unless otherwise stated
Figure 2. INL vs Code
Figure 3. DNL vs Code
Figure 4. INL / DNL vs VREF
Figure 5. INL / DNL vs FSCLK
Figure 6. INL / DNL vs VA
Figure 7. INL / DNL vs Temperature
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Typical Characteristics (continued)
VA = 2.7 V to 5.5 V, VREF1,2 = VA, fSCLK = 30 MHz, TA = 25°C, unless otherwise stated
12
Figure 8. Zero Code Error vs VA
Figure 9. Zero Code Error vs VREF
Figure 10. Zero Code Error vs FSCLK
Figure 11. Zero Code Error vs Temperature
Figure 12. Full-Scale Error vs VA
Figure 13. Full-Scale Error vs VREF
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Typical Characteristics (continued)
VA = 2.7 V to 5.5 V, VREF1,2 = VA, fSCLK = 30 MHz, TA = 25°C, unless otherwise stated
Figure 14. Full-Scale Error vs FSCLK
Figure 15. Full-Scale Error vs Temperature
Figure 16. IVA vs VA
Figure 17. IVA vs Temperature
Figure 18. IVREF vs VREF
Figure 19. IVREF vs Temperature
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Typical Characteristics (continued)
VA = 2.7 V to 5.5 V, VREF1,2 = VA, fSCLK = 30 MHz, TA = 25°C, unless otherwise stated
14
Figure 20. Settling Time
Figure 21. Glitch Response
Figure 22. Wake-Up Time
Figure 23. DAC-to-DAC Crosstalk
Figure 24. Power-On Reset
Figure 25. Multiplying Bandwidth
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8 Detailed Description
8.1 Overview
The DAC128S085 is fabricated on a CMOS process with an architecture that consists of switches and resistor
strings followed by an output buffer. The reference voltages are externally applied at VREF1 for DAC channels A
through D, and VREF2 for DAC channels E through H.
8.2 Functional Block Diagram
VREF1
DAC128S085
REF
12 BIT DAC
VOUTA
BUFFER
12
2.5k
100k
REF
12 BIT DAC
VOUTB
BUFFER
12
POWER-ON
RESET
2.5k
100k
REF
12 BIT DAC
VOUTC
BUFFER
12
2.5k
100k
REF
12 BIT DAC
VOUTD
BUFFER
12
2.5k
100k
REF
12 BIT DAC
DAC
REGISTER
VOUTE
BUFFER
12
2.5k
100k
REF
12 BIT DAC
VOUTF
BUFFER
12
2.5k
100k
REF
12 BIT DAC
VOUTG
BUFFER
12
2.5k
100k
12
REF
12 BIT DAC
VOUTH
BUFFER
12
2.5k
DOUT
SYNC
SCLK
100k
POWER-DOWN
CONTROL
LOGIC
INPUT
CONTROL
LOGIC
DIN
VREF2
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8.3 Feature Description
8.3.1 DAC Architecture
For simplicity, a single resistor string is shown in Figure 26. This string consists of 4096 equal valued resistors
with a switch at each junction of two resistors, plus a switch to ground. The code loaded into the DAC register
determines which switch is closed, connecting the proper node to the amplifier. The input coding is straight
binary with an ideal output voltage of:
VOUTA,B,C,D = VREF1 × (D / 4096)
where
• D is the decimal equivalent of the binary code that is loaded into the DAC register.
VOUTE,F,G,H = VREF2 × (D / 4096)
(1)
(2)
D can take on any value between 0 and 4095. This configuration ensures that the DAC is monotonic.
VREF
R
S2 n
R
R
S2 n-1
VOUT
S2 n-2
S2
R
S1
R
S0
Figure 26. DAC Resistor String
Because all eight DAC channels of the DAC128S085 can be controlled independently, each channel consists of
a DAC register and a 12-bit DAC. Figure 27 is a simple block diagram of an individual channel in the
DAC128S085. Depending on the mode of operation, data written into a DAC register causes the 12-bit DAC
output to be updated, or an additional command is required to update the DAC output. Further description of the
modes of operation can be found in Serial Interface.
VREF
REF
DAC
REGISTER
12 BIT DAC
12
BUFFER
VOUT
Figure 27. Single-Channel Block Diagram
16
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Feature Description (continued)
8.3.2 Output Amplifiers
The output amplifiers are rail-to-rail, providing an output voltage range of 0 V to VA when the reference is VA. All
amplifiers, including rail-to-rail types, exhibit a loss of linearity as the output approaches the supply rails (0 V and
VA, in this case). For this reason, linearity is specified over less than the full output range of the DAC. However, if
the reference is less than VA, only the lowest codes experience a loss in linearity.
The output amplifiers can drive a load of 2 kΩ in parallel with 1500 pF to ground or to VA. The zero-code and fullscale outputs for given load currents are available in the Electrical Characteristics.
8.3.3 Reference Voltage
The DAC128S085 uses dual external references, VREF1 and VREF2, which are shared by channels A, B, C, D and
channels E, F, G, H, respectively. The reference pins are not buffered and have an input impedance of 30 kΩ. TI
recommends driving VREF1 and VREF2 by voltage sources with low output impedance. The reference voltage
range is 0.5 V to VA, providing the widest possible output dynamic range.
8.3.4 Serial Interface
The three-wire interface is compatible with SPI, QSPI, and MICROWIRE, as well as most DSPs, and operates at
clock rates up to 40 MHz. A valid serial frame contains 16 falling edges of SCLK. See Table 1 for information on
a write sequence.
A write sequence begins by bringing the SYNC line low. Once SYNC is low, the data on the DIN line is clocked
into the 16-bit serial input register on the falling edges of SCLK. To avoid mis-clocking data into the shift register,
it is critical that SYNC not be brought low on a falling edge of SCLK (see minimum and maximum setup times for
SYNC in AC and Timing Characteristics and Figure 28). On the 16th falling edge of SCLK, the last data bit is
clocked into the register. The write sequence is concluded by bringing the SYNC line high. Once SYNC is high,
the programmed function (a change in the DAC channel address, mode of operation, or register contents) is
executed. To avoid mis-clocking data into the shift register, it is critical that SYNC be brought high between the
16th and 17th falling edges of SCLK (see minimum and maximum hold times for SYNC in AC and Timing
Characteristics and Figure 28).
SCLK
1
15
tSS
17
16
tSH
SYNC
Figure 28. CS Setup and Hold Times
If SYNC is brought high before the 15th falling edge of SCLK, the write sequence is aborted and the data that
has been shifted into the input register is discarded. If SYNC is held low beyond the 17th falling edge of SCLK,
the serial data presented at DIN will begin to be output on DOUT. More information on this mode of operation can
be found in Daisy-Chain Operation. In either case, SYNC must be brought high for the minimum specified time
before the next write sequence is initiated with a falling edge of SYNC.
Since the DIN buffer draws more current when it is high, it should be idled low between write sequences to
minimize power consumption. On the other hand, SYNC should be idled high to avoid the activation of daisy
chain operation where DOUT is active.
8.3.5 Daisy-Chain Operation
Daisy-chain operation allows communication with any number of DAC128S085s using a single serial interface.
As long as the correct number of data bits are input in a write sequence (multiple of sixteen bits), a rising edge of
SYNC will properly update all DACs in the system.
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Feature Description (continued)
To support multiple devices in a daisy chain configuration, SCLK and SYNC are shared across all DAC128S085s
and DOUT of the first DAC in the chain is connected to DIN of the second. Figure 29 shows three DAC128S085s
connected in daisy chain fashion. Similar to a single channel write sequence, the conversion for a daisy chain
operation begins on a falling edge of SYNC and ends on a rising edge of SYNC. A valid write sequence for n
devices in a chain requires n times 16 falling edges to shift the entire input data stream through the chain. Daisy
chain operation is ensured for a maximum SCLK speed of 30 MHz.
SYNC
SCLK
DIN
SYNC
SCLK
SYNC
SCLK
SYNC
SCLK
DIN DOUT
DIN DOUT
DIN DOUT
DAC 1
DAC 2
DAC 3
Figure 29. Daisy-Chain Configuration
The serial data output pin, DOUT, is available on the DAC128S085 to allow daisy-chaining of multiple
DAC128S085 devices in a system. In a write sequence, DOUT remains low for the first 14 falling edges of SCLK
before going high on the 15th falling edge. Subsequently, the next 16 falling edges of SCLK will output the first
16 data bits entered into DIN. Figure 30 shows the timing of 3 DAC128S085s in Figure 29. In this instance, It
takes 48 falling edges of SCLK followed by a rising edge of SYNC to load all three DAC128S085s with the
appropriate register data. On the rising edge of SYNC, the programmed function is executed in each
DAC128S085 simultaneously.
When connecting multiple devices in a daisy-chain configuration, it is important to note that the DAC128S085 will
update the DOUT signal on the falling edge of SCLK, and this will be sampled by the next DAC in the daisy chain
on the next falling edge of the clock. Ensure that the timing requirements are met for proper operation.
Specifically, pay attention to the data hold time after the SCLK falling (tDH) requirement. Improper layout or
loading may delay the clock signal between devices. If delayed to the point that data changes prior to meeting
the hold time requirement, incorrect data can be sampled. If the clock delay cannot be resolved, an alternative
solution is to add a delay between the DOUT of one device and DIN of the following device in the daisy chain. This
increases the hold time margin and allows for correct sampling. Be aware though, that the tradeoff with this fix is
that too much delay eventually impacts the setup time.
48 SCLK Cycles (16 X 3)
SYNC
DIN1
DAC 3
DIN2/DOUT1
th
15 SCLK Cycle
DAC 2
DAC 1
DAC 3
DAC 2
st
31 SCLK Cycle
DIN3/DOUT2
DAC 3
Data Loaded into the DACs
Figure 30. Daisy Chain Timing Diagram
8.3.6 DAC Input Data Update Mechanism
The DAC128S085 has two modes of operation, plus a few special command operations. The two modes of
operation are Write Register Mode (WRM) and Write Through Mode (WTM). For the rest of this document, these
modes will be referred to as WRM and WTM. The special command operations are separate from WRM and
WTM because they can be called upon regardless of the current mode of operation. The mode of operation is
controlled by the first four bits of the control register, DB15 through DB12. See Table 1 for a detailed summary.
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Feature Description (continued)
Table 1. Write Register and Write Through Modes
DB[15:12]
DB[11:0]
Description of Mode
1000
XXXXXXXXXXXX
WRM: The registers of each DAC Channel can be written to without causing
their outputs to change.
1001
XXXXXXXXXXXX
WTM: Writing data to a channel's register causes the DAC output to change.
When the DAC128S085 first powers up, the DAC is in WRM. In WRM, the registers of each individual DAC
channel can be written to without updating the DAC outputs. This is accomplished by setting DB15 to 0,
specifying the DAC register to be written to in DB[14:12], and entering the new DAC register setting in DB[11:0]
(see Table 2). The DAC128S085 remains in WRM until the mode of operation is changed to WTM. The mode of
operation is changed from WRM to WTM by setting DB[15:12] to 1001. Once in WTM, writing data to a DAC
channel register causes the DAC output to be updated as well. Changing a DAC channel register in WTM is
accomplished in the same manner as in WRM. However, in WTM the DAC register and output are updated at the
completion of the command (see Table 2). Similarly, the DAC128S085 remains in WTM until the mode of
operation is changed to WRM by setting DB[15:12] to 1000.
Table 2. Commands Impacted by WRM and WTM
DB15
DB[14:12]
DB[11:0]
Description of Mode
0
000
D11 D10 ... D1 D0
WRM: D[11:0] written to ChA's data register only
WTM: ChA's output is updated by data in D[11:0]
0
001
D11 D10 ... D1 D0
WRM: D[11:0] written to only the data register of ChB
WTM: ChB's output is updated by data in D[11:0]
0
010
D11 D10 ... D1 D0
WRM: D[11:0] written to only the data register of ChC
WTM: ChC's output is updated by data in D[11:0]
0
011
D11 D10 ... D1 D0
WRM: D[11:0] written only the data register of ChD
WTM: ChD's output is updated by data in D[11:0]
0
100
D11 D10 ... D1 D0
WRM: D[11:0] written only the data register of ChE
WTM: ChE's output is updated by data in D[11:0]
0
101
D11 D10 ... D1 D0
WRM: D[11:0] written only the data register of ChF
WTM: ChF's output is updated by data in D[11:0]
0
110
D11 D10 ... D1 D0
WRM: D[11:0] written only the data register of ChG
WTM: ChG's output is updated by data in D[11:0]
0
111
D11 D10 ... D1 D0
WRM: D[11:0] written only the data register of ChH
WTM: ChH's output is updated by data in D[11:0]
The special command operations can be exercised at any time regardless of the mode of operation. There are
three special command operations. The first command is exercised by setting data bits DB[15:12] to 1010. This
allows the user to update multiple DAC outputs simultaneously to the values currently loaded in their respective
control registers. This command is valuable if the user wants each DAC output to be at a different output voltage,
but still have all the DAC outputs changed to their appropriate values simultaneously (see Table 3).
The second special command allows the user to alter the DAC output of channel A with a single write frame.
This command is exercised by setting data bits DB[15:12] to 1011 and data bits DB[11:0] to the desired control
register value. This command also causes the DAC outputs of the other channels to update to their current
control register values. The user may choose to exercise this command to save a write sequence. For example,
the user may wish to update several DAC outputs simultaneously, including channel A. To accomplish this task
in the minimum number of write frames, the user would alter the control register values of all the DAC channels
except channel A while operating in WRM. The last write frame would be used to exercise the special command
Channel A Write Mode. In addition to updating the control register of channel A and output to a new value, all of
the other channels would be updated as well. At the end of this sequence of write frames, the DAC128S085
would still be operating in WRM (see Table 3).
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The third special command allows the user to set all the DAC control registers and outputs to the same level.
This command is commonly referred to as "broadcast" mode, as the same data bits are being broadcast to all of
the channels simultaneously. This command is exercised by setting data bits DB[15:12] to 1100 and data bits
DB[11:0] to the value that the user wishes to broadcast to all the DAC control registers. Once the command is
exercised, each DAC output is updated by the new control register value. This command is frequently used to set
all the DAC outputs to some known voltage such as 0 V, VREF/2, or Full Scale. A summary of the commands can
be found in Table 3.
Table 3. Special Command Operations
DB[15:12]
DB[11:0]
Description of Mode
1010
XXXXHGFEDCBA
Update Select: The DAC outputs of the channels selected with a 1 in DB[7:0]
are updated simultaneously to the values in their respective control registers.
1011
D11 D10 ... D1 D0
Channel A Write: The control register and DAC output of channel A are
updated to the data in DB[11:0]. The outputs of the other seven channels are
also updated according to their respective control register values.
1100
D11 D10 ... D1 D0
Broadcast: The data in DB[11:0] is written to all channel control registers and
DAC output simultaneously.
8.3.7 Power-On Reset
The power-on reset circuit controls the output voltages of the eight DACs during power-up. Upon application of
power, the DAC registers are filled with zeros and the output voltages are set to 0 V. The outputs remain at 0 V
until a valid write sequence is made.
8.3.8 Transfer Characteristic
FSE
4095 x VA
4096
GE = FSE - ZE
FSE = GE + ZE
OUTPUT
VOLTAGE
ZE
0
0
4095
DIGITAL INPUT CODE
Figure 31. Input / Output Transfer Characteristic
8.4 Device Functional Modes
8.4.1 Power-Down Modes
The DAC128S085 has three power-down modes, where different output terminations can be selected (see
Table 4). With all channels powered down, the supply current drops to 0.1 µA at 3 V and 0.2 µA at 5 V. By
selecting the channels to be powered down in DB[7:0] with a 1, individual channels can be powered down
separately, or multiple channels can be powered down simultaneously. The three different output terminations
include high output impedance, 100 kΩ to ground, and 2.5 kΩ to ground.
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Device Functional Modes (continued)
The output amplifiers, resistor strings, and other linear circuitry are all shut down in any of the power-down
modes. The bias generator, however, is only shut down if all the channels are placed in power-down mode. The
contents of the DAC registers are unaffected when in power-down. Therefore, each DAC register maintains its
value prior to the DAC128S085 being powered down unless it is changed during the write sequence that
instructed it to recover from power down. Minimum power consumption is achieved in the power-down mode with
SYNC idled high, DIN idled low, and SCLK disabled. The time to exit power-down (Wake-Up Time) is typically 3
µsec at 3 V and 20 µsec at 5 V.
Table 4. Power-Down Modes
DB[15:12]
DB[11:8]
7
6
4
3
2
1
0
1101
XXXX
H
G
F
5
E
D
C
B
A
Output Impedance
Hi-Z outputs
1110
XXXX
H
G
F
E
D
C
B
A
100 kΩ outputs
1111
XXXX
H
G
F
E
D
C
B
A
2.5 kΩ outputs
8.5 Programming
8.5.1 Programming the DAC128S085
This section presents the step-by-step instructions for programming the serial input register.
8.5.1.1 Updating DAC Outputs Simultaneously
When the DAC128S085 is first powered on, the DAC is operating in Write Register Mode (WRM). Operating in
WRM allows the user to program the registers of multiple DAC channels without causing the DAC outputs to be
updated. For example, below are the steps for setting Channel A to a full scale output, Channel B to threequarters full scale, Channel C to half-scale, Channel D to one-quarter full scale and having all the DAC outputs
update simultaneously.
As stated previously, the DAC128S085 powers up in WRM. If the device was previously operating in Write
Through Mode (WTM), an extra step to set the DAC into WRM is required. First, the DAC registers must be
programmed to the desired values. To set Channel A to an output of full scale, write 0FFF to the control register.
This updates the data register for Channel A without updating the output of Channel A. Second, set Channel B to
an output of three-quarters full scale by writing 1C00 to the control register. This updates the data register for
Channel B. Once again, the output of Channel B and Channel A are not updated, because the DAC is operating
in WRM. Third, set Channel C to half scale by writing 2800 to the control register. Fourth, set Channel D to onequarter full scale by writing 3400 to the control register. Finally, update all four DAC channels simultaneously by
writing A00F to the control register. This procedure allows the user to update four channels simultaneously with
five steps.
Because Channel A was one of the DACs to be updated, one command step could have been saved by writing
to Channel A last. Do this by writing to Channel B, C, and D first, and using the the special command Channel A
Write to update the DAC register and output of Channel A. This special command also updates all DAC outputs
while updating Channel A. With this sequence of commands, the user can update four channels simultaneously
using four steps. A summary of this command can be found in Table 3.
8.5.1.2 Updating DAC Outputs Independently
If the DAC128S085 is currently operating in WRM, change the mode of operation to WTM by writing 9XXX to the
control register. Once the DAC is operating in WTM, any DAC channel can be updated in one step. For example,
if a design required Channel G to be set to half scale, the user can write 6800 to the control register to update
the data register and DAC output of Channel G. Similarly, write 5FFF to the control register to set the output of
Channel F to full scale. Channel A is the only channel that has a special command that allows its DAC output to
be updated in one command, regardless of the mode of operation. Write BFFF to the control register to set the
DAC output of Channel A to full scale in one step.
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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
9.1.1 Using References as Power Supplies
While the simplicity of the DAC128S085 implies ease of use, it is important to recognize that the path from the
reference input (VREF1,2) to the DAC outputs has a zero Power Supply Rejection Ratio (PSRR). Therefore, the
user must provide a noise-free supply voltage to VREF1,2. To utilize the full dynamic range of the DAC128S085,
the supply pin (VA) and VREF1,2 can be connected together and share the same supply voltage. Because the
DAC128S085 consumes very little power, a reference source can be used as the reference input or the supply
voltage. The advantages of using a reference source over a voltage regulator are accuracy and stability. Some
low-noise regulators can also be used. Listed below are a few reference and power supply options for the
DAC128S085.
9.2 Typical Application
The LM4132, with its ±0.05% accuracy over temperature, is a good choice as a reference source for the
DAC128S085. The 4.096-V version is useful for a 0-V to 4.095-V output range. Bypassing the LM4132 voltage
input pin with a 4.7-µF capacitor and the voltage output pin with a 4.7-µF capacitor improves stability and
reduces output noise. The LM4132 comes in a space-saving 5-pin SOT-23.
5V
LM4132-4.1
VIN
4.7 µF
EN
VREF
GND
4.7 µF
0.1 µF
R
3.3 V
VA
VDD
VREF1
100
GPIOa
To Load
VREF2
VOUTA
C
SCLK
100
GPIOb
SYNC
Master
R
DAC128C085
100
VOUTD
To Load
DOUT
GPIOc
100
C
DIN
GPIOd
VOUTH
GND
R
GND
To Load
C
Figure 32. The LM4132 as a Power Supply
9.2.1 Design Requirements
There are two references for the DAC128S085. One reference input serves channels A through D, while the
other reference serves channels E through H. The 16-bit input shift register of the DAC128S085 controls the
mode of operation, the power-down condition, and the register/output value of the DAC channels. All eight DAC
outputs can be updated simultaneously or individually.
9.2.2 Detailed Design Procedure
Each reference input pin can be set independently, or the reference pins can be shorted together as shown in
Figure 32. Acceptable reference voltages are 0.5 V to VA. Utilizing an RC filter on the output to roll off output
noise is optional.
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Typical Application (continued)
9.2.3 Application Curve
Figure 33. Typical Performance
10 Power Supply Recommendations
For best performance, the DAC128S085 power supply should be bypassed with at least a 1-µF and a 0.1-µF
capacitor. The 0.1-µF capacitor must be placed right at the device supply pin. The 1-µF or larger valued
capacitor can be a tantalum capacitor, while the 0.1-µF capacitor must be a ceramic capacitor with low ESL and
low ESR. If a ceramic capacitor with low ESL and low ESR is used for the 1-µF value and can be placed right at
the supply pin, the 0.1-µF capacitor can be eliminated. Capacitors of this nature typically span the same
frequency spectrum as the 0.1-µF capacitor, and thus eliminate the need for the extra capacitor. The power
supply for the DAC128S085 should only be used for analog circuits.
Avoid the crossover of analog and digital signals. This helps minimize the amount of noise from the transitions of
the digital signals from coupling onto the sensitive analog signals, such as the reference pins and the DAC
outputs.
11 Layout
11.1 Layout Guidelines
For best accuracy and minimum noise, the printed circuit board containing the DAC128S085 should have
separate analog and digital areas. The areas are defined by the locations of the analog and digital power planes.
Both of these planes should be located in the same board layer. A single ground plane is preferred if digital
return current does not flow through the analog ground area. Frequently a single ground plane design will utilize
a "fencing" technique to prevent the mixing of analog and digital ground current. Separate ground planes should
only be utilized when the fencing technique is inadequate. The separate ground planes must be connected in
one place, preferably near the DAC128S085. Ensure that digital signals with fast edge rates do not pass over
split ground planes. The signals must always have a continuous return path below their traces.
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DAC128S085
SNAS407H – AUGUST 2007 – REVISED APRIL 2015
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11.2 Layout Example
To MCU
SCLK
DOUT
SYNC
DAC128S085
DIN
VOUTA
VOUTB
To loads
VOUTC
VOUTE
VOUTF
VOUTG
VOUTH
VA
GND
VREF1
VREF2
N.C.
GND
EN
LM4132
VOUTD
VREF
To loads
VIA to GROUND PLANE
GROUND PLANE
VIN
5-V Supply Rail
Figure 34. Layout Example
24
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DAC128S085
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SNAS407H – AUGUST 2007 – REVISED APRIL 2015
12 Device and Documentation Support
12.1 Device Support
12.1.1 Specification Definitions
DIFFERENTIAL NON-LINEARITY (DNL) is the measure of the maximum deviation from the ideal step size of 1
LSB, which is VREF / 4096 = VA / 4096.
DAC-to-DAC CROSSTALK is the glitch impulse transferred to a DAC output in response to a full-scale change
in the output of another DAC.
DIGITAL CROSSTALK is the glitch impulse transferred to a DAC output at mid-scale in response to a full-scale
change in the input register of another DAC.
DIGITAL FEEDTHROUGH is a measure of the energy injected into the analog output of the DAC from the digital
inputs when the DAC outputs are not updated. It is measured with a full-scale code change on the
data bus.
FULL-SCALE ERROR is the difference between the actual output voltage with a full scale code (FFFh) loaded
into the DAC and the value of VA x 4095 / 4096.
GAIN ERROR is the deviation from the ideal slope of the transfer function. It can be calculated from Zero and
Full-Scale Errors as GE = FSE - ZE, where GE is Gain error, FSE is Full-Scale Error and ZE is
Zero Error.
GLITCH IMPULSE is the energy injected into the analog output when the input code to the DAC register
changes. It is specified as the area of the glitch in nanovolt-seconds.
INTEGRAL NON-LINEARITY (INL) is a measure of the deviation of each individual code from a straight line
through the input to output transfer function. The deviation of any given code from this straight line
is measured from the center of that code value. The end point method is used. INL for this product
is specified over a limited range, per the Electrical Tables.
LEAST SIGNIFICANT BIT (LSB) is the bit that has the smallest value or weight of all bits in a word. This value
is
LSB = VREF / 2n
where
•
VREF is the supply voltage for this product, and n is the DAC resolution in bits, which is 12 for the
DAC128S085.
(3)
MAXIMUM LOAD CAPACITANCE is the maximum capacitance that can be driven by the DAC with output
stability maintained.
MONOTONICITY is the condition of being monotonic, where the DAC has an output that never decreases when
the input code increases.
MOST SIGNIFICANT BIT (MSB) is the bit that has the largest value or weight of all bits in a word. Its value is
1/2 of VA.
MULTIPLYING BANDWIDTH is the frequency at which the output amplitude falls 3 dB below the input sine
wave on VREF1,2 with the DAC code at full-scale.
NOISE SPECTRAL DENSITY is the internally generated random noise. It is measured by loading the DAC to
mid-scale and measuring the noise at the output.
POWER EFFICIENCY is the ratio of the output current to the total supply current. The output current comes from
the power supply. The difference between the supply and output currents is the power consumed
by the device without a load.
SETTLING TIME is the time for the output to settle to within 1/2 LSB of the final value after the input code is
updated.
TOTAL HARMONIC DISTORTION PLUS NOISE (THD+N) is the ratio of the harmonics plus the noise present
at the output of the DACs to the rms level of an ideal sine wave applied to VREF1,2 with the DAC
code at mid-scale.
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DAC128S085
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Device Support (continued)
WAKE-UP TIME is the time for the output to exit power-down mode. This is the time from the rising edge of
SYNC to when the output voltage deviates from the power-down voltage of 0 V.
ZERO CODE ERROR is the output error, or voltage, present at the DAC output after a code of 000h has been
entered.
12.2 Documentation Support
12.2.1 Related Documentation
•
LM4132 SOT-23 Precision Low Dropout Voltage Reference, SNVS372
12.3 Trademarks
SPI is a trademark of Motorola, Inc..
All other trademarks are the property of their respective owners.
12.4 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
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.
26
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PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
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)
DAC128S085CIMT/NOPB
ACTIVE
TSSOP
PW
16
92
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
X78C
DAC128S085CIMTX/NOPB
ACTIVE
TSSOP
PW
16
2500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
X78C
DAC128S085CISQ/NOPB
ACTIVE
WQFN
RGH
16
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
128S085
DAC128S085CISQX/NOPB
ACTIVE
WQFN
RGH
16
4500
RoHS & Green
SN
Level-1-260C-UNLIM
-40 to 125
128S085
(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
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