LTC1605-1/LTC1605-2
Single Supply 16-Bit, 100ksps,
Sampling ADCs
Features
Description
Sample Rate: 100ksps
nn Complete 16-Bit Solution on a Single 5V Supply
nn Unipolar Input Range: 0V to 4V (LTC1605-1)
nn Bipolar Input Range: ±4V (LTC1605-2)
nn Power Dissipation: 55mW Typ
nn Signal-to-Noise Ratio: 86dB Typ
nn Operates with Internal or External Reference
nn Internal Synchronized Clock
nn 28-Pin SSOP Package
The LTC ®1605-1/LTC1605-2 are 100ksps, sampling
16-bit A/D converters that draw only 55mW (typical) from
a single 5V supply. These easy-to-use devices include a
sample-and-hold, precision reference, switched capacitor
successive approximation A/D and trimmed internal clock.
Applications
The ADC has a microprocessor compatible, 16-bit or two
byte parallel output port. A convert start input and a data
ready signal (BUSY) ease connections to FIFOs, DSPs and
microprocessors.
nn
The LTC1605-1’s input range is 0V to 4V while the
LTC1605-2’s input range is ±4V. An external reference
can be used if greater accuracy over temperature is
needed.
Industrial Process Control
Multiplexed Data Acquisition Systems
nn High Speed Data Acquisition for PCs
nn Digital Signal Processing
nn
nn
L, LTC and LT are registered trademarks of Linear Technology Corporation.
Typical Application
LTC1605-1 Low Power, 100kHz, 16-Bit Sampling ADC on 5V Supply
5V
10μF
28
0.1μF
Typical INL Curve
27
2.0
VDIG VANA
1 VIN
4k
16-BIT
SAMPLING ADC
33.2k
2.5V
20k
2.5V
BUSY 26
BUFFER
3 REF
D15 TO D0
1.5
16-BIT
OR 2 BYTE
PARALLEL
BUS
10k
4 CAP
2.2μF
6 TO 13
15 TO 22
CONTROL
LOGIC AND
TIMING
2.5V
REFERENCE
4k
2
AGND2
5
R/C 24
DIGITAL
CONTROL
SIGNALS
BYTE 23
2.2μF
AGND1
CS 25
DGND
14
1.0
INL (LSBs)
0V TO 4V 200Ω
INPUT
0.5
0
–0.5
–1.0
–1.5
–2.0
0
16384
32768
49152
65535
CODE
1605-1/2 TA01
1605-1/2 TA02/G04
160512fa
For more information www.linear.com/LTC1605-1
1
LTC1605-1/LTC1605-2
Absolute Maximum Ratings
(Notes 1, 2)
VANA ...........................................................................7V
VDIG to VANA .............................................................0.3V
VDIG ............................................................................7V
Ground Voltage Difference
DGND, AGND1 and AGND2.................................±0.3V
Analog Inputs (Note 3)
VIN ......................................................................±25V
CAP.............................. VANA + 0.3V to AGND2 – 0.3V
REF.....................................Indefinite Short to AGND2
Momentary Short to VANA
Digital Input Voltage (Note 4).......... VDGND – 0.3V to 10V
Digital Output Voltage......... VDGND – 0.3V to VDIG + 0.3V
Power Dissipation............................................... 500mW
Operating Ambient Temperature Range
LTC1605-1C/LTC1605-2C.......................... 0°C to 70°C
LTC1605-1I/LTC1605-2I........................–40°C to 85°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec).................... 300°C
Pin Configuration
TOP VIEW
TOP VIEW
VIN 1
28 VDIG
AGND1 2
27 VANA
REF 3
26 BUSY
CAP 4
25 CS
AGND2 5
D15 (MSB) 6
24 R/C
23 BYTE
D14 7
22 D0
D13 8
21 D1
D12 9
20 D2
D11 10
19 D3
D10 11
18 D4
D9 12
17 D5
D8 13
16 D6
DGND 14
15 D7
VIN 1
28 VDIG
AGND1 2
27 VANA
REF 3
26 BUSY
CAP 4
25 CS
AGND2 5
D15 (MSB) 6
23 BYTE
D14 7
22 D0
D13 8
21 D1
D12 9
20 D2
D11 10
19 D3
D10 11
18 D4
D9 12
17 D5
D8 13
16 D6
DGND 14
15 D7
N PACKAGE
28-LEAD PDIP
G PACKAGE
28-LEAD PLASTIC SSOP
TJMAX = 125°C, θJA = 95°C/W
EXPOSED PAD (PIN #) IS GND, MUST BE SOLDERED TO PCB
2
24 R/C
TJMAX = 125°C, θJA = 130°C/W
OBSOLETE PACKAGE
160512fa
For more information www.linear.com/LTC1605-1
LTC1605-1/LTC1605-2
Order Information
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC1605-1CG#PBF
LTC1605-1CG#TRPBF
LTC1605-1CG
28-Lead Plastic SSOP
0°C to 70°C
LTC1605-1IG#PBF
LTC1605-1IG#TRPBF
LTC1605-1IG
28-Lead Plastic SSOP
–40°C to 85°C
LTC1605-2CG#PBF
LTC1605-2CG#TRPBF
LTC1605-2CG
28-Lead Plastic SSOP
0°C to 70°C
LTC1605-2IG#PBF
LTC1605-2IG#TRPBF
LTC1605-2IG
28-Lead Plastic SSOP
–40°C to 85°C
OBSOLETE PACKAGE
LTC1605-1CN#PBF
LTC1605-1CN#TRPBF
LTC1605-1CN
28-Lead PDIP
0°C to 70°C
LTC1605-1IN#PBF
LTC1605-1IN#TRPBF
LTC1605-1IN
28-Lead PDIP
–40°C to 85°C
LTC1605-2CN#PBF
LTC1605-2CN#TRPBF
LTC1605-2CN
28-Lead PDIP
0°C to 70°C
LTC1605-2IN#PBF
LTC1605-2IN#TRPBF
LTC1605-2IN
28-Lead PDIP
–40°C to 85°C
Consult factory for Military grade parts.
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on nonstandard lead based finish parts.
For more information on lead free part markings, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
Converter
Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. With external reference (Notes 5, 6).
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Resolution
l
16
Bits
No Missing Codes
l
15
Bits
Transition Noise
1
LSBRMS
Integral Linearity Error
(Note 7)
l
±3
LSB
Zero Error
Ext. Reference = 2.5V (Note 8)
l
±10
mV
Zero Error Drift
±2
Full-Scale Error Drift
ppm/°C
±7
Full-Scale Error
Ext. Reference = 2.5V (Notes 12, 13)
Full-Scale Error Drift
Ext. Reference = 2.5V
Power Supply Sensitivity
VANA = VDIG = VDD
VDD = 5V ±5% (Note 9)
ppm/°C
±0.50
l
±2
%
ppm/°C
±8
LSB
Analog
Input
The l denotes the specifications which apply over the full operating temperature range, otherwise
specifications are at TA = 25°C. (Note 5)
SYMBOL PARAMETER
VIN
Analog Input Range (Note 9)
CIN
RIN
CONDITIONS
4.75V ≤ VANA ≤ 5.25V, 4.75V ≤ VDIG ≤ 5.25V
LTC1605-1
LTC1605-2
MIN
TYP
MAX
UNITS
0 to 4
±4
V
V
Analog Input Capacitance
10
pF
Analog Input Impedance
10
kΩ
l
l
160512fa
For more information www.linear.com/LTC1605-1
3
LTC1605-1/LTC1605-2
Dynamic Accuracy
The l denotes the specifications which apply over the full operating temperature range,
otherwise specifications are at TA = 25°C. (Notes 5, 14)
SYMBOL PARAMETER
CONDITIONS
MIN
S/(N + D) Signal-to-(Noise + Distortion) Ratio
1kHz Input Signal (Note 14)
10kHz Input Signal
20kHz, –60dB Input Signal
THD
Total Harmonic Distortion
TYP
MAX
UNITS
87
85
30
dB
dB
dB
1kHz Input Signal, First 5 Harmonics
10kHz Input Signal, First 5 Harmonics
–101
-92
dB
dB
Peak Harmonic or Spurious Noise
1kHz Input Signal
10kHz Input Signal
–101
-92
dB
dB
Full-Power Bandwidth
(Note 15)
275
kHz
40
ns
Aperture Delay
Aperture Jitter
Sufficient to Meet AC Specs
Transient Response
Full-Scale Step (Note 9)
Overvoltage Recovery
(Note 16)
2
µs
150
ns
Internal Reference Characteristics
The l denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at TA = 25°C. (Note 5)
PARAMETER
CONDITIONS
VREF Output Voltage
IOUT = 0
VREF Output Tempco
IOUT = 0
l
MIN
TYP
MAX
UNITS
2.470
2.500
2.520
V
Internal Reference Source Current
External Reference Voltage for Specified Linearity
(Notes 9, 10)
External Reference Current Drain
Ext. Reference = 2.5V (Note 9)
CAP Output Voltage
IOUT = 0
2.30
±5
ppm/°C
1
µA
2.50
l
2.70
V
100
µA
2.50
V
Digital Inputs and Digital Outputs
The l denotes the specifications which apply over the
full operating temperature range, otherwise specifications are at TA = 25°C. (Note 5)
SYMBOL PARAMETER
CONDITIONS
MIN
VIH
High Level Input Voltage
VDD = 5.25V
l
VIL
Low Level Input Voltage
VDD = 4.75V
l
VIN = 0V to VDD
l
IIN
Digital Input Current
CIN
Digital Input Capacitance
VOH
High Level Output Voltage
VDD = 4.75V
IO = –10µA
IO = –200µA
l
IO = 160µA
TYP
MAX
2.4
UNITS
V
0.8
V
±10
µA
5
pF
4.5
V
0.05
V
4.0
V
VOL
Low Level Output Voltage
VDD = 4.75V
0.4
V
IOZ
Hi-Z Output Leakage D15 to D0
VOUT = 0V to VDD, CS High
l
±10
µA
COZ
Hi-Z Output Capacitance D15 to D0
CS High (Note 9)
l
15
pF
ISOURCE
Output Source Current
VOUT = 0V
–10
mA
ISINK
Output Sink Current
VOUT = VDD
10
mA
IO = 1.6mA
4
l
0.10
160512fa
For more information www.linear.com/LTC1605-1
LTC1605-1/LTC1605-2
Timing Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 5)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
fSAMPLE(MAX) Maximum Sampling Frequency
l
tCONV
Conversion Time
l
8
µs
tACQ
Acquisition Time
l
2
µs
kHz
100
t1
Convert Pulse Width
(Note 11)
l
t2
Data Valid Delay After R/C↓
(Note 9)
l
8
CL = 50pF
l
65
ns
8
µs
t3
BUSY Delay from R/C↓
t4
BUSY Low
t5
BUSY Delay After End of Conversion
t6
Aperture Delay
t7
t8
Bus Relinquish Time
BUSY Delay After Data Valid
t9
Previous Data Valid After R/C↓
t10
R/C to CS Setup Time
t11
Time Between Conversions
t12
Bus Access and Byte Delay
ns
40
µs
ns
220
ns
40
l
l
10
50
35
200
83
ns
ns
µs
7.4
(Notes 9, 10)
(Notes 9, 10)
10
ns
10
µs
10
83
ns
Power Requirements
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 5)
SYMBOL
PARAMETER
CONDITIONS
MIN
VDD
Positive Supply Voltage
(Notes 9, 10)
4.75
IDD
Positive Supply Current
PDIS
Power Dissipation
l
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: All voltage values are with respect to ground with DGND, AGND1
and AGND2 wired together (unless otherwise noted).
Note 3: When these pin voltages are taken below ground or above VANA =
VDIG = VDD, they will be clamped by internal diodes. This product can
handle input currents of greater than 100mA below ground or above VDD
without latch-up.
Note 4: When these pin voltages are taken below ground, they will be
clamped by internal diodes. This product can handle input currents of
90mA below ground without latchup. These pins are not clamped to VDD.
Note 5: VDD = 5V, fSAMPLE = 100kHz, tr = tf = 5ns unless otherwise
specified.
Note 6: Linearity, offset and full-scale specifications apply for a VIN input
with respect to ground.
Note 7: Integral nonlinearity is defined as the deviation of a code from a
straight line passing through the actual end points of the transfer curve.
The deviation is measured from the center of the quantization band.
Note 8: Zero error for the LTC1605-1 is the voltage measured from
0.5LSB when the output code flickers between 0000 0000 0000 0000
TYP
MAX
5.25
UNITS
V
11
16
mA
55
80
mW
and 0000 0000 0000 0001. Zero error for the LTC1605-2 is the voltage
measured from – 0.5LSB when the output code flickers between 0000
0000 0000 0000 and 1111 1111 1111 1111.
Note 9: Guaranteed by design, not subject to test.
Note 10: Recommended operating conditions.
Note 11: With CS low the falling R/C edge starts a conversion. If R/C
returns high at a critical point during the conversion it can create small
errors. For best results ensure that R/C returns high within 3µs after the
start of the conversion.
Note 12: As measured with fixed resistors shown in Figure 4. Adjustable to
zero with external potentiometer.
Note 13: Full-scale error is the untrimmed deviation from ideal last code
transition, divided by the full-scale range and includes the effect of offset
error.
Note 14: All specifications in dB are referred to a full-scale 4V input for the
LTC1605-1 and to ±4V input for the LTC1605-2.
Note 15: Full-power bandwidth is defined as full-scale input frequency
at which a signal-to-(noise + distortion) degrades to 60dB or 10 bits of
accuracy.
Note 16: Recovers to specified performance after (±20V) input
overvoltage for the LTC1605-1 and ±15V for the LTC1605-2.
160512fa
For more information www.linear.com/LTC1605-1
5
LTC1605-1/LTC1605-2
Typical Performance Characteristics
Supply Current vs Supply Voltage
12.5
12.0
fSAMPLE = 100kHz
11.0
10.5
10.0
5.00
5.25
5.50
CHANGE IN CAP VOLTAGE (V)
POWER SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
11.5
4.75
0.04
fSAMPLE = 100kHz
12.0
9.5
4.50
11.5
11.0
10.5
10.0
–50
–25
0
25
50
TEMPERATURE (˚C)
75
2.0
1.5
1.5
1.0
1.0
0.5
0.5
0
–0.5
–1.0
100
49152
0
–0.5
–2.0
65535
0
CODE
16384
32768
49152
–60
LTC1605-1
–70
LTXXXX GXX
TOTAL HARMONIC DISTORTION (dB)
86
84
1605-1/2 G07/F11
80
1M
–70
82
10 15 20 25 30 35 40 45 50
FREQUENCY (kHz)
1k
10k
100k
RIPPLE FREQUENCY (Hz)
Total Harmonic Distortion vs
Input Frequency (LTC1605-2)
88
SINAD (dB)
MAGNITUDE (dB)
–50
–80
100
65535
90
5
LTC1605-2
–40
SINAD vs Input Frequency
(LTC1605-2)
fSAMPLE = 100kHz
fIN = 1kHz
SINAD = 87dB
THD = 101.1dB
SNR = 87.2dB
10
–30
1605-1/2 G05
LTC1605-2 Nonaveraged
4096-Point FFT Plot
0
1605-1/2 G03
CODE
1605-1/2 TA02/G04
0
LTC1605-1
–0.10
–80 –70 –60 –50 –40 –30 –20 –10
LOAD CURRENT (mA)
–20
–1.5
32768
LTC1605-2
–0.06
Power Supply Feedthrough
vs Ripple Frequency
–1.0
–1.5
6
–0.04
POWER SUPPLY FEEDTHROUGH (dB)
2.0
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
–120
–130
–0.02
Typical DNL Curve
DNL (LSB)
INL (LSBs)
Typical INL Curve
16384
0
1605-1/2 G02
1605-1/2 G01
0
0.02
–0.08
SUPPLY VOLTAGE (V)
–2.0
Change in CAP Voltage vs
Load Current
Supply Current vs Temperature
1
10
INPUT FREQUENCY (kHz)
100
1605-1/2 G08
–80
–90
–100
–110
1
10
INPUT FREQUENCY (kHz)
100
1605-1/2 G09
160512fa
For more information www.linear.com/LTC1605-1
LTC1605-1/LTC1605-2
Pin Functions
VIN (Pin 1): Analog Input. Connect through a 200Ω
resistor to the analog input. Full-scale input range is 0V
to 4V for the LTC1605-1 and ±4V for the LTC1605-2.
AGND1 (Pin 2): Analog Ground. Tie to analog ground
plane.
REF (Pin 3): 2.5V Reference Output. Bypass with 2.2µF
tantalum capacitor. Can be driven with an external reference.
CAP (Pin 4): Reference Buffer Output. Bypass with 2.2µF
tantalum capacitor.
AGND2 (Pin 5): Analog Ground. Tie to analog ground plane.
D15 to D8 (Pins 6 to 13): T hree-State Data Outputs.
Hi-Z state when CS is high or when R/C is low.
DGND (Pin 14): Digital Ground.
D7 to D0 (Pins 15 to 22): T hree-State Data Outputs.
Hi-Z state when CS is high or when R/C is low.
BYTE (Pin 23): Byte Select. With BYTE low, data will be
output with Pin 6 (D15) being the MSB and Pin 22 (D0)
being the LSB. With BYTE high the upper eight bits and
the lower eight bits will be switched. The MSB is output
on Pin 15 and bit 8 is output on Pin 22. Bit 7 is output on
Pin 6 and the LSB is output on Pin 13.
R/C (Pin 24): Read/Convert Input. With CS low, a falling
edge on R/C puts the internal sample-and-hold into the
hold state and starts a conversion. With CS low, a rising
edge on R/C enables the output data bits.
CS (Pin 25): Chip Select. Internally OR’d with R/C. With
R/C low, a falling edge on CS will initiate a conversion. With
R/C high, a falling edge on CS will enable the output data.
utput Shows Converter Status. It is low
BUSY (Pin 26): O
when a conversion is in progress. Data valid on the rising
edge of BUSY. CS or R/C must be high when BUSY rises
or another conversion will start without time for signal
acquisition.
VANA (Pin 27): 5V Analog Supply. Bypass to ground with
a 0.1µF ceramic and a 10µF tantalum capacitor.
VDIG (Pin 28): 5V Digital Supply. Connect directly to
Pin 27.
Functional Block Diagram
VIN
4k
6K*
CSAMPLE
10k
OPEN*
REF
4k
20k
3.75k*
VANA
CSAMPLE
VDIG
ZEROING SWITCHES
2.5V REF
+
REF BUF
COMP
16-BIT CAPACITIVE DAC
–
CAP
(2.5V)
AGND1
AGND2
DGND
16
SUCCESSIVE APPROXIMATION
REGISTER
INTERNAL
CLOCK
•
•
•
OUTPUT LATCHES
D15
D0
CONTROL LOGIC
*RESISTOR VALUES FOR THE LTC1605-2
CS
R/C
BYTE
BUSY
1605-1/2 BD
160512fa
For more information www.linear.com/LTC1605-1
7
LTC1605-1/LTC1605-2
Test Circuits
Load Circuit for Output Float Delay
Load Circuit for Access Timing
5V
5V
1k
DBN
1k
DBN
1k
DBN
DBN
CL
CL
1k
50pF
1605-1/2 TC02
1605-1/2 TC01
A. HI-Z TO VOH AND VOL TO VOH
B. HI-Z TO VOL AND VOH TO VOL
50pF
A. VOH TO HI-Z
B. VOL TO HI-Z
Applications information
Conversion Details
The LTC1605-1/LTC1605-2 use a successive approximation algorithm and an internal sample-and-hold circuit to
convert an analog signal to a 16-bit or two byte parallel
output. The ADC is complete with a precision reference and
an internal clock. The control logic provides easy interface
to microprocessors and DSPs. (Please refer to the Digital
Interface section for the data format.)
Conversion start is controlled by the CS and R/C inputs.
At the start of conversion, the successive approximation
register (SAR) is reset. Once a conversion cycle has begun,
it cannot be restarted.
During the conversion, the internal 16-bit capacitive DAC
output is sequenced by the SAR from the most significant
bit (MSB) to the least significant bit (LSB). Referring to
Figure 1, VIN is connected through the resistor divider
and S1 to the sample-and-hold capacitor during the
acquire phase and the comparator offset is nulled by the
SAMPLE
VIN
RIN1
RIN2
S1
SAMPLE
S3
CSAMPLE
–
HOLD
S2
+
CDAC
DAC
VDAC
COMPARATOR
S
A
R
16-BIT
LATCH
autozero switch, S3. In this acquire phase, a minimum
delay of 2µs will provide enough time for the sample-andhold capacitor to acquire the analog signal. During the
convert phase, S3 opens, putting the comparator into the
compare mode. The input switch S2 switches CSAMPLE
to ground, injecting the analog input charge onto the
summing junction. This input charge is successively
compared with the binary-weighted charges supplied by
the capacitive DAC. Bit decisions are made by the high
speed comparator. At the end of a conversion, the DAC
output balances the VIN input charge. The SAR contents
(a 16-bit data word) that represents the VIN are loaded
into the 16-bit output latches.
Driving the Analog Inputs
The nominal input range for the LTC1605-1 is 0V to 4V or
(1.6VREF) and for the LTC1605-2 the input range is ±4V
or (±1.6VREF). The inputs are overvoltage protected to
±25V. The input impedance is typically 10kΩ; therefore,
it should be driven by a low impedance source. Wideband
noise coupling into the input can be minimized by placing
a 1000pF capacitor at the input as shown in Figure 2. An
NPO-type capacitor gives the lowest distortion. Place the
capacitor as close to the device input pin as possible. If
an amplifier is to be used to drive the input, care should
be taken to select an amplifier with adequate accuracy,
linearity and noise for the application. The following list
is a summary of the op amps that are suitable for driving
the LTC1605-1/LTC1605-2. More detailed information
is available in the Linear Technology data books and
LinearViewTM CD-ROM.
1605-1/2 F01
Figure 1. LTC1605-1/LTC1605-2 Simplified Equivalent Circuit
8
LinearView is a trademark of Linear Technology Corporation
160512fa
For more information www.linear.com/LTC1605-1
LTC1605-1/LTC1605-2
Applications information
LT®1007 - Low noise precision amplifier. 2.7mA supply
current ±5V to ±15V supplies. Gain bandwidth product
8MHz. DC applications.
LT1097 - Low cost, low power precision amplifier. 300µA
supply current. ±5V to ±15V supplies. Gain bandwidth
product 0.7MHz. DC applications.
LT1227 - 140MHz video current feedback amplifier. 10mA
supply current. ±5V to ±15V supplies. Low noise and low
distortion.
LT1360 - 37MHz voltage feedback amplifier. 3.8mA supply
current. ±5V to ±15V supplies. Good AC/DC specs.
LT1363 - 50MHz voltage feedback amplifier. 6.3mA supply
current. Good AC/DC specs.
LT1364/LT1365 - Dual and quad 50MHz voltage feedback
amplifiers. 6.3mA supply current per amplifier. Good AC/
DC specs.
LT1468 - 90MHz, 22V/µs 16-Bit Accurate Amplifier
AIN
200Ω
VIN
1000pF
33.2k
CAP
1605-1/2 F02
Figure 2. Analog Input Filtering
Internal Voltage Reference
The LTC1605-1/LTC1605-2 has an on-chip, temperature
compensated, curvature corrected, bandgap reference,
which is factory trimmed to 2.50V. The full-scale range
of the ADC is equal to (1.6VREF) or nominally 0V to 4V
for the LTC1605-1 and (±1.6VREF) or nominally ±4V for
the LTC1605-2. The output of the reference is connected
to the input of a unity-gain buffer through a 4k resistor
(see Figure 3). The input to the buffer or the output of the
reference is available at REF (Pin 3). The internal reference can be overdriven with an external reference if more
accuracy is needed. The buffer output drives the internal
DAC and is available at CAP (Pin 4). The CAP pin can be
used to drive a steady DC load of less than 2mA. Driving
an AC load is not recommended because it can cause the
performance of the converter to degrade.
For minimum code transition noise the REF pin and the
CAP pin should each be decoupled with a capacitor to
filter wideband noise from the reference and the buffer
(2.2µF tantalum).
Offset and Gain Adjustments
The LTC1605-1/LTC1605-2 offset and full-scale errors have been trimmed at the factory with the external
resistors shown in Figure 4. This allows for external
adjustment of offset and full scale in applications where
absolute accuracy is important. See Figure 5 for the offset and gain trim circuit for the LTC1605-1/LTC1605-2.
First adjust the offset to zero by adjusting resistor R3.
Apply an input voltage of 30.5µV (0.5LSB) and adjust R3
so the code is changing between 0000 0000 0000 0001
and 0000 0000 0000 0000. The gain error is trimmed by
adjusting resistor R4. An input voltage of 3.999908V (FS
– 1.5LSB) is applied to VIN and R4 is adjusted until the
output code is changing between 1111 1111 1111 1110
and 1111 1111 1111 1111. Figure 6a shows the unipolar
transfer characteristic of the LTC1605-1.
For the LTC1605-2, first adjust the offset to zero by
adjusting resistor R3. Apply an input voltage of –61µV
(–0.5LSB) and adjust R3 so the code is changing between
1111 1111 1111 1111 and 0000 0000 0000 0000. The gain
error is trimmed by adjusting resistor R4. An input voltage
of 3.999817V (+FS – 1.5LSB) is applied to VIN and R4 is
adjusted until the output code is changing between 0111
1111 1111 1110 and 0111 1111 1111 1111. Figure 6b
shows the bipolar transfer characteristics of the LTC1605-2.
DC Performance
One way of measuring the transition noise associated with
a high resolution ADC is to use a technique where a DC
signal is applied to the input of the ADC and the resulting output codes are collected over a large number of
conversions. For example, in Figure 7 the distribution of
output code is shown for a DC input that has been digitized
10000 times. The distribution is Gaussian and the RMS
code transition is about 1LSB.
160512fa
For more information www.linear.com/LTC1605-1
9
LTC1605-1/LTC1605-2
Applications information
111...111
4k
3
2.2μF
BANDGAP
REFERENCE
VANA
+
–
4
CAP
(2.5V)
111...110
OUTPUT CODE
REF
(2.5V)
INTERNAL
CAPACITOR
DAC
2.2μF
UNIPOLAR
ZERO
000...001
FS = 4V
1LSB = FS/65536
000...000
0V 1
LSB
1605-1/2 F03
Figure 3. Internal or External Reference Source
FS – 1LSB
INPUT VOLTAGE (V)
1605-1/2 F06a
Figure 6a. LTC1605-1 Unipolar Transfer Characteristics
011...111
1
2
200Ω
1%
33.2k
1%
+
+
2.2μF
3
4
2.2μF
5
BIPOLAR
ZERO
011...110
VIN
AGND1
OUTPUT CODE
0V TO 4V
OR ±4V
INPUT
LTC1605-1
LTC1605-2
REF
CAP
AGND2
000...001
000...000
111...111
111...110
100...001
1605-1/2 F04
FS = 8V
1LSB = FS/65536
100...000
Figure 4. 0V to 4V Input for the LTC1605-1
and ±4V for the LTC1605-2 Without Trim
– FS/2
–1 0V 1
LSB
LSB
INPUT VOLTAGE (V)
FS/2 – 1LSB
1605-1/2 F06b
Figure 6B. LTC1605-2 Bipolar Transfer Characteristics
0V TO 4V
OR ±4V
INPUT 200Ω
1%
2
+
GAIN
TRIM
5V
R4
50k
OFFSET
TRIM
R3
50k
+
4500
VIN
3000
REF
576k
4
2.2μF
3500
LTC1605-1
LTC1605-2
2.2μF
3
4000
AGND1
COUNT
33.2k
1%
1
5
CAP
2500
2000
1500
1000
AGND2
1605-1/2 F05
500
0
Figure 5. 0V to 4V Input for the LTC1605-1 and
±4V for the LTC1605-2 with Offset and Gain Trim
–5 –4 –3 –2 –1 0 1
CODE
2
3
4
5
1605-1/2 F07
Figure 7. Histogram for 10000 Conversions
10
160512fa
For more information www.linear.com/LTC1605-1
LTC1605-1/LTC1605-2
Applications information
Digital Interface
Internal Clock
The ADC has an internal clock that is trimmed to achieve
a typical conversion time of 7µs. No external adjustments
are required and, with the typical acquisition time of 1µs,
throughput performance of 100ksps is assured.
Timing and Control
Conversion start and data read are controlled by two
digital inputs: CS and R/C. To start a conversion and put
the sample-and-hold into the hold mode, bring CS and
R/C low for no less than 40ns. Once initiated, it cannot
be restarted until the conversion is complete. Converter
status is indicated by the BUSY output and this is low
while the conversion is in progress.
There are two modes of operation. The first mode is shown
in Figure 8. The digital input R/C is used to control the
start of conversion. CS is tied low. When R/C goes low,
the sample-and-hold goes into the hold mode and a conversion is started. BUSY goes low and stays low during
the conversion and will go back high after the conversion
has been completed and the internal output shift registers
have been updated. R/C should remain low for no less than
40ns. During the time R/C is low, the digital outputs are in
a Hi-Z state. R/C should be brought back high within 3µs
after the start of the conversion to ensure that no errors
occur in the digitized result. The second mode, shown in
Figure 9, uses the CS signal to control the start of a conversion and the reading of the digital output. In this mode,
the R/C input signal should be brought low no less than
10ns before the falling edge of CS. The minimum pulse
width for CS is 40ns. When CS falls, BUSY goes low and
will stay low until the end of the conversion. BUSY will go
high after the conversion has been completed. The new
data is valid when CS is brought back low again to initiate
a read. Again, it is recommended that both R/C and CS
return high within 3µs after the start of the conversion.
Output Data
The output data can be read as a 16-bit word or it can be
read as two 8-bit bytes. The format of the output data is
straight binary for the LTC1605-1 and two’s complement
for the LTC1605-2. The digital input pin BYTE is used to
control the two byte read. With the BYTE pin low, the first
eight MSBs are output on the D15 to D8 pins and the eight
LSBs are output on the D7 to D0 pins. When the BYTE
pin is taken high, the eight LSBs replace the eight MSBs
(Figure 10).
t1
R/C
t 11
t2
t4
t3
BUSY
t6
MODE
t5
ACQUIRE
t9
DATA MODE
PREVIOUS
DATA VALID
HI-Z
t7
CONVERT
ACQUIRE
t CONV
t ACQ
PREVIOUS
DATA VALID
CONVERT
DATA
VALID
NOT VALID
t8
HI-Z
DATA
VALID
1605-1/2 F08
Figure 8. Conversion Timing with Outputs Enabled After Conversion (CS Tied Low)
160512fa
For more information www.linear.com/LTC1605-1
11
LTC1605-1/LTC1605-2
Applications information
t 10
t 10
t 10
t 10
R/C
t1
t1
CS
t3
t4
BUSY
t6
MODE
ACQUIRE
CONVERT
ACQUIRE
t CONV
HI-Z
DATA BUS
DATA
VALID
t 12
t7
HI-Z
1605-1/2 F09
Figure 9. Using CS to Control Conversion and Read Timing
t 10
t 10
R/C
CS
BYTE
PINS 6 TO 13
HI-Z
HIGH BYTE
t 12
PINS 15 TO 22
HI-Z
t 12
LOW BYTE
HI-Z
LOW BYTE
t7
HIGH BYTE
HI-Z
1605-1/2 F10
Figure 10. Using CS and BYTE to Control Data Bus Read Timing
12
160512fa
For more information www.linear.com/LTC1605-1
LTC1605-1/LTC1605-2
Applications information
Dynamic Performance
FFT (Fast Fourier Transform) test techniques are used to
test the ADC’s frequency response, distortion and noise
at the rated throughput. By applying a low distortion sine
wave and analyzing the digital output using an FFT algorithm, the ADC’s spectral content can be examined for
frequencies outside the fundamental. Figure 11 shows a
typical LTC1605-2 FFT plot which yields a SINAD of 87dB
and THD of –101.1dB.
Signal-to-Noise Ratio
The Signal-to-Noise and Distortion Ratio (SINAD) is the
ratio between the RMS amplitude of the fundamental input
frequency to the RMS amplitude of all other frequency
components at the A/D output. The output is band limited
to frequencies from above DC and below half the sampling
frequency. Figure 11 shows a typical SINAD of 87dB with
a 100kHz sampling rate and a 1kHz input.
fSAMPLE = 100kHz
fIN = 1kHz
SINAD = 87dB
THD = 101.1dB
SNR = 87.2dB
MAGNITUDE (dB)
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
–120
–130
0
5
10 15 20 25 30 35 40 45 50
FREQUENCY (kHz)
1605-1/2 G07/F11
Figure 11. LTC1605-2 Nonaveraged 4096-Point FFT Plot
Total Harmonic Distortion
Total Harmonic Distortion (THD) is the ratio of the RMS
sum of all harmonics of the input signal to the fundamental
itself. The out-of-band harmonics alias into the frequency
band between DC and half the sampling frequency. THD
is expressed as:
THD = 20log
where V1 is the RMS amplitude of the fundamental
frequency and V2 through VN are the amplitudes of the
second through Nth harmonics.
Board Layout, Power Supplies and Decoupling
Wire wrap boards are not recommended for high resolution or high speed A/D converters. To obtain the best
performance from the LTC1605-1/LTC1605-2, a printed
circuit board is required. Layout for the printed circuit
board should ensure the digital and analog signal lines
are separated as much as possible. In particular, care
should be taken not to run any digital track alongside an
analog signal track or underneath the ADC. The analog
input should be screened by AGND.
Figures 12 through 15 show a layout for a suggested evaluation circuit which will help obtain the best performance
from the 16-bit ADC. Additional information regarding the
evaluation circuit and Gerber files for the PC board layout
are available from Linear Technology or your local sales
office. Pay particular attention to the design of the analog
and digital ground planes. The DGND pin of the LTC1605-1/
LTC1605-2 can be tied to the analog ground plane. Placing
the bypass capacitor as close as possible to the power
supply, the reference and reference buffer output is very
important. Low impedance common returns for these
bypass capacitors are essential to low noise operation of
the ADC, and the PC track width for these lines should be
as wide as possible. Also, since any potential difference in
grounds between the signal source and ADC appears as
an error voltage in series with the input signal, attention
should be paid to reducing the ground circuit impedance
as much as possible. The digital output latches and the
onboard sampling clock have been placed on the digital
ground plane. The two ground planes are tied together at
the power supply ground connection.
V22 + V32 + V42... + VN2
V1
160512fa
For more information www.linear.com/LTC1605-1
13
LTC1605-1/LTC1605-2
Applications Information
Figure 12. Component Side Silkscreen for the Suggested LTC1605-1/LTC1605-2 Evaluation Circuit
ANALOG
GROUND PLANE
DIGITAL
GROUND PLANE
Figure 13. Bottom Side Showing Analog Ground Plane
14
ANALOG
GROUND PLANE
Figure 14. Component Side Showing Separate Analog
and Digital Ground Plane
160512fa
For more information www.linear.com/LTC1605-1
2
1
For more information www.linear.com/LTC1605-1
2
1
2
R17
51
GND
NA
OUT
U8
1MHz, OSC
EXT_CLK
1
J1
J2
AIN
GND
E2
3
3
4
3
2
1
2
3
4
5
6
7
10
9
1
NC2
+
8
TRIM
GND
QD
QC
QB
QA
C
B
A
RCO
D
ENP
ENT
CLK
LOAD
CLR
14
13
12
11
15
5
6
JP1
R18
200Ω
1%
VCC
R21, 2k
3
CLK
13
4
CS
VCC 3
VCC
Q
Q
GND 1
RCEXT
CEXT
B
A
JP5
2
C3
0.1μF
C4
2.2μF
C16
1000pF
C9
0.1μF
C8
0.1μF
C7
10μF
VKK
C5
0.1μF
R19
33.2k
1%
C10
0.1μF
28
27
26
25
24
23
14
5
4
3
2
1
VDIG
VANA
BUSY
CS
R/C
BYTE
DGND
AGND2
CAP
REF
AGND1
VIN
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
U1
LTC1605-1
LTC1605-2
C11
0.1μF
VCC
D12
D13
D14
D15
U4B
74HC04
3
4
22 D0
21 D1
20 D2
19 D3
18 D4
17 D5
16 D6
15 D7
13 D8
12 D9
11 D10
10 D11
9
8
7
6
C12
0.1μF
R20
1K
C13
0.1μF
6
D11
1
5
D12
1
C1
15PF
11
9
8
D6
D7
7
D5
6
5
D3
D4
4
3
2
11
9
8
D2
D1
D0
D8
D9
7
4
D13
D10
3
2
D14
D15
C14
0.1μF
Figure 15. LTC1605-1 Suggested Evaluation Circuit Schematic
15
2
1
JP4
2
C2
2.2μF
U6A
74HC221
NORNAL 1
BYTE
REVERSE 3
C17
10μF
EXT VREF INT
VCC VDD
JP3
2
C6
22μF
10V
R16
20
INT 1 VCC
CLK
EXT 3
U4E
74HC04
11
10
U9
LT1019-2.5
OUT
TEMP
7
8
VKK
INPUT HEATER
NC1
D16
MBR0520
U7
74HC160
U4D
74HC04
VCC
9
VKK
VIN
U5
LT1121
GND
2
VIN
7V TO 15V
1
E1
VIN
DIGITAL I.C. BYPASSING
Q7
U4C
74HC04
5
6
CLK
OC
D7
Q6
D6
Q4
D4
Q5
Q3
D3
D5
Q2
Q1
D1
D2
Q0
D0
U3
74HC574
CLK
OC
Q7
Q6
D6
D7
Q5
Q4
Q3
Q2
Q1
Q0
D5
D4
D3
D2
D1
D0
U2
74HC574
C15
10μF
19
12
13
14
15
16
17
18
19
1
U4A
74HC04
12
13
14
15
16
17
18
2
R0, 1.2k
R1, 1.2k
R2, 1.2k
R3, 1.2k
R4, 1.2k
R5, 1.2k
R6, 1.2k
R7, 1.2k
R8, 1.2k
R9, 1.2k
R10, 1.2k
R11, 1.2k
R12, 1.2k
R13, 1.2k
R14, 1.2k
R15, 1.2k
20
19
18
17
16
15
14
D7
D0
D1
D2
D3
D4
D5
D6
GND
GND
CLK
D15
D0
D1
D2
D3
D4
13
D5
12
D6
11
D7
10
D8
D9
D10
D11
D12
D13
D14
D15
9
8
7
6
5
4
3
2
1
D8
D9
D10
D11
D12
D13
D14
D15
1605-1/2 F15
JP2
LED
ENABLE
LTC1605-1/LTC1605-2
Applications information
160512fa
15
LTC1605-1/LTC1605-2
Typical Applications
The circuit in Figure 16 is an example showing the
LTC1605 16-bit A/D converter and LTC1391 8-channel
MUX connected to a 68HC11 controller. The LTC1605’s
16-bit data output is read in two 8-bit bytes using Pins
6 (MSB, Bit7) through 13 (Bit8, Bit0), connected to the
HC11’s PORTC. The MUX’s 4-bit serial address data is
sent using the controller’s SPI.
The process to convert a channel’s input signal is shown
in sample listing A. It begins with shifting in the MUX’s
channel data while the SS signal is a logic high. The MUX
channel address is latched on the falling edge of SS and
the chosen channel’s input is applied at the LTC1605’s
input, Pin 1. Through the processor’s PORTA, a low-going
pulse is applied to the LTC1605’s R/C pin, initiating a conversion. The processor then monitors the BUSY output.
When this signal becomes a logic high, signaling the end
of conversion, the processor reads the high byte of the
conversion through PORTC. The low byte is read through
PORTC when the processor changes the BYTE signal to a
logic high. The timing relationship of the control signals
and data are shown in Figure 17.
Sample Listing A
*************************************************************************
* *
* This example program selects the an LTC1391 MUX channel, initiates a *
* conversion, and retrieves conversion data. It stores the 16-bit data *
* in two consecutive memory locations. The program is designed for use *
* with the LTC1605’s /CS tied to ground (see timing diagram in
*
* Figure 17). *
* *
*************************************************************************
*
*****************************************
* 68HC11 register definitions
*
*****************************************
*
$1000 Parallel port A
PORTA EQU
*
Use Bit0 as an input for the LTC1605’s /BUSY signal
*
Use Bit3 as an output driving the LTC1605’s BYTE
* input
PIOC EQU
$1002 Parallel I/O control register
*
“STAF,STAI,CWOM,HNDS, OIN, PLS, EGA,INVB”
PORTC EQU
$1003 Port C data register
* “Bit7,Bit6,Bit5,Bit4,Bit3,Bit2,Bit1,Bit0”
DDRC EQU
$1007 Port D data direction register
* “Bit7,Bit6,Bit5,Bit4,Bit3,Bit2,Bit1,Bit0”
*
1 = output, 0 = input
PORTD EQU
$1008 Port D data register
*
“ - , - , SS* ,CSK ;MOSI,MISO,TxD ,RxD “
DDRD EQU
$1009 Port D data direction register
SPCR EQU
$1028 SPI control register
* “SPIE,SPE ,DWOM,MSTR;SPOL,CPHA,SPR1,SPR0”
SPSR EQU
$1029 SPI status register
*
“SPIF,WCOL, - ,MODF; - , - , - , - “
SPDR EQU
$102A SPI data register; Read-Buffer; Write-Shifter
*
* RAM variables to hold the LTC1605’s 14 conversion result
*
DIN1 EQU
$00
This memory location holds the LTC1605’s bits 15 - 08
DIN2 EQU
$01
This memory location holds the LTC1605’s bits 07 - 00
MUX
EQU
$02
This memory location holds the MUX address data
*
16
For more information www.linear.com/LTC1605-1
160512fa
LTC1605-1/LTC1605-2
Typical Applications
*****************************************
* Start GETDATA Routine
*
*****************************************
*
ORG
$C000 Program start location
LDAA #$03 0,0,0,0,0,0,1,1
INIT1
*
“STAF=0,STAI=0,CWOM=0,HNDS=0, OIN=0, PLS=0, EGA=1,INVB=1”
STAA PIOC Ensures that the PIOC register’s status is the same
*
as after a reset, necessary of simple Port D manipulation
LDAA #$00 0,0,0,0,0,0,0,0
“Bits 7 - 0 are used as inputs for the LTC1605’s data
*
STAA DDRC Direction of PortD’s bit are now set as inputs
LDAA #$2F -,-,1,0;1,1,1,1
*
-, -, SS*-Hi, SCK-Lo, MOSI-Hi, MISO-Hi, X, X
STAA PORTD Keeps SS* a logic high when DDRD, Bit5 is set
LDAA #$38 -,-,1,1;1,0,0,0
STAA DDRD SS* , SCK, MOSI are configured as Outputs
*
MISO, TxD, RxD are configured as Inputs
* DDRD’s Bit5 is a 1 so that port D’s SS* pin is a general output
LDAA #$50
STAA SPCR The SPI is configured as Master, CPHA = 0, CPOL = 0
*
and the clock rate is E/2
*
(This assumes an E-Clock frequency of 4MHz. For higher
*
E-Clock frequencies, change the above value of $50 to a
*
value that ensures the SCK frequency is 2MHz or less.)
GETDATA PSHX
PSHY
PSHA
*
*****************************************
* Setup indices
*
*****************************************
*
LDX
#$0
The X register is used as a pointer to the memory
*
locations that hold the conversion data
LDY #$1000
*
*****************************************
* Ensure that a logic high is applied
*
* to the LTC1391’s /CS and the
*
* LTC1605’s R/C pins
*
*****************************************
*
BSET PORTD,Y %00100000
This sets the SS* output bit to a logic
*
high, ensuring that the LTC1391’s CS*
*
input is a logic high while clocking
*
MUX address data into the LTC1391
BSET PORTA,Y %00010000
This sets the R/C* output bit to a logic
*
high, ensuring that the LTC1605’s R/C*
*
input is a logic high before initiating
* a conversion
*****************************************
160512fa
For more information www.linear.com/LTC1605-1
17
LTC1605-1/LTC1605-2
Typical Applications
* Retrieve the MUX address from memory
*
* and send it to the LTC1391
*
*****************************************
*
LDAA MUX
Retrieve the MUX address from memory
ORAA #$08 Enable the selected MUX address
STAA SPDR Select the MUX channel
WAIT1 LDAA SPSR This loop waits for the SPI to complete a serial
*
transfer/exchange by reading the SPI Status Register
BPL
WAIT1 The SPIF (SPI transfer complete flag) bit is the SPSR’s
MSB and is set to one at the end of an SPI transfer. The
*
*
branch will occur while SPIF is a zero.
BCLR PORTD,Y %00100000
This forces a logic low on PORTD’s SS*,
* latching the MUXes data
*
*****************************************
* Initiate a LTC1605 conversion
*
*****************************************
*
BCLR PORTA,Y %00010000
Initiate a conversion
BSET PORTA,Y %00010000
This sets the LTC1605’s R/C* to a logic
* high
*
*****************************************
* Set the LTC1605’s BYTE input low to
*
* ensure that the high byte is present *
* during the first read
*
*****************************************
*
LDAA PORTA
Get the contents of Port A
ANDA #%11110111
Set Bit3 low
STAA PORTA
Set the LTC1605’s BYTE input low
*
*****************************************
* The next short loop ensures that the *
* LTC1605’s conversion is finished *
* before starting the data transfer
*
*****************************************
*
CONVEND
LDAA PORTA
Retrieve the contents of port A
ANDA #%00000001
Look at Bit0
*
Bit0 = Lo; the LTC1605’s conversion is not
* complete
*
Bit0 = Hi; the LTC1605’s conversion is complete
BEQ
CONVEND
Branch to the loop’s beginning while Bit7
* remains low
*
18
160512fa
For more information www.linear.com/LTC1605-1
LTC1605-1/LTC1605-2
Typical Applications
*************************************************************************
*
* This routine retrieves the LTC1605’s 16-bit data using two 8-bit
* reads. The BYTE input is manipulated through Port A’s Bit3. During *
* the first read when BYTE is low, the upper byte is read and stored in *
* DIN1. During the second read when BYTE is high, the lower byte is *
* read and stored in DIN2.
*
*************************************************************************
*
LDAA PORTC Retrieve the LTC1605’s high byte
STAA DIN1 Store the high byte
LDAA PORTA Get the contents of Port A
ORAA #%00001000
Set Bit3 high
STAA PORTA Set the LTC1605’s BYTE input high
LDAA PORTC Retrieve the LTC1605’s low byte
STAA DIN2 Store the high byte
PULA
Restore the A register
PULY
Restore the Y register
PULX
Restore the X register
RTS
5V
1
2
3
4
5
6
7
S0
V+
S1
D
S2
16
5V
0.1μF
3
15
14
V–
S3
DOUT
S4
DIN
S5
CS
S6
DLK
S7
DGND
13
5V
0.1μF
2
+
8
1/2 LT1630
–
4
12
11
10
5V
0.1μF
1
200Ω
1%
USE FOR LTC1605-2
M0S1
SS
CLK
1
22
4
+
–5V SUPPLY FOR
LTC1605-2
5
2.2μF
3
2
SPI
VIN
CAP
AGND2
REF
AGND1
21
17
20
16
19
14
15
26
DGND
BUSY
10μF
1μF
28
VDIG
27
VANA
6
D7/D15
7
D6/D14
8
D5/D13
9
D4/D12
10
D3/D11
11
D2/D10
12
D1/D9
13
D0/D8
18
33.2k
1%
2.2μF
9
LTC1605-1
LTC1605-2
+
8
LTC1391
25
CS
24
R/C
23
BYTE
PORTC, BIT7
PORTC, BIT6
PORTC, BIT5
PORTC, BIT4
PORTC, BIT3
PORTC, BIT2
PORTC, BIT1
PORTC, BIT0
PORTA, BIT0
PORTA, BIT4
PORTA, BIT3
1605-1/2 F16
Figure 16. 8-Channel, 16-Bit Data Acquisition System with Interface to the 68HC11
160512fa
For more information www.linear.com/LTC1605-1
19
LTC1605-1/LTC1605-2
Package Description
Dimensions in inches (millimeters) unless otherwise noted.
G Package
28-Lead Plastic SSOP (0.209)
(LTC DWG # 05-08-1640)
10.07 – 10.33*
(0.397 – 0.407)
28 27 26 25 24 23 22 21 20 19 18 17 16 15
7.65 – 7.90
(0.301 – 0.311)
1 2 3 4 5 6 7 8 9 10 11 12 13 14
5.20 – 5.38**
(0.205 – 0.212)
1.73 – 1.99
(0.068 – 0.078)
0˚ – 8˚
0.13 – 0.22
(0.005 – 0.009)
0.65
(0.0256)
BSC
0.55 – 0.95
(0.022 – 0.037)
NOTE: DIMENSIONS ARE IN MILLIMETERS
*DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.152mm (0.006") PER SIDE
**DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.254mm (0.010") PER SIDE
0.05 – 0.21
(0.002 – 0.008)
0.25 – 0.38
(0.010 – 0.015)
G28 SSOP 1098
N Package
28-Lead Plastic
PDIP (Narrow .300 Inch)
N Package
(Reference
DWG
# 05-08-1510
Rev I)
28-LeadLTC
PDIP
(Narrow
0.300)
(Reference LTC DWG # 05-08-1510 Rev I)
1.400*
(35.560)
MAX
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
.240 – .295*
(6.096 – 7.493)
.300 – .325
(7.620 – 8.255)
.045 – .065
(1.143 – 1.651)
.130 ±.005
(3.302 ±0.127)
.020
(0.508)
MIN
.008 – .015
(0.203 – 0.381)
(
+.035
.325 –.015
+0.889
8.255
–0.381
NOTE:
1. DIMENSIONS ARE
)
.120
(3.048)
MIN
.065
(1.651)
TYP
N28 REV I 0711
.005
(0.127)
MIN
.100
(2.54)
BSC
.018 ±.003
(0.457 ±0.076)
OBSOLETE PACKAGE
INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
20
160512fa
For more information www.linear.com/LTC1605-1
LTC1605-1/LTC1605-2
Revision History
REV
DATE
DESCRIPTION
A
07/15
Obsoleted 28-Lead PDIP Package
PAGE NUMBER
2, 20
160512fa
Information furnished by Linear Technology corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation
Forofmore
information
www.linear.com/LTC1605-1
that the interconnection
its circuits
as described
herein will not infringe on existing patent rights.
21
LTC1605-1/LTC1605-2
Typical Application
MUX
CS
MUX
DATA
CH0
CH1
CH2
R/C
BUSY
BYTE
ADC
DATA
HI BYTE
LO BYTE
HI BYTE
DATA 0
LO BYTE
HI BYTE
LO BYTE
DATA 1
1605-1/2 F17
Figure 17. This Is the Timing Relationship Between the Selected MUX Channel, Its Conversion Data
and the ADC and MUX Control Signals When Using the Sample Program In Listing 1. The Conversion
Process Is Latency Free: the Data Is Always Generated Based On the Currently Selected MUX Input
Related Parts
PART NUMBER
DESCRIPTION
COMMENTS
LT®1019-2.5
Precision Bandgap Reference
0.05% Max, 5ppm/°C Max
LTC1274/LTC1277
Low Power 12-Bit, 100ksps ADCs
10mW Power Dissipation, Parallel/Byte Interface
LTC1415
Single 5V, 12-Bit, 1.25Msps ADC
55mW Power Dissipation, 72dB SINAD
LTC1419
Low Power 14-Bit, 800ksps ADC
True 14-Bit Linearity, 81.5dB SINAD, 150mW Dissipation
LT1460-2.5
Micropower Precision Series Reference
0.075% Max, 10ppm/°C Max, Only 130µA Supply Current
LTC1594/LTC1598
Micropower 4-/8-Channel 12-Bit ADCs
Serial I/O, 3V and 5V Versions
LTC1604
16-Bit, 333ksps Sampling ADC
±2.5V Input, 90dB SINAD, 100dB THD
LTC1605
Low Power 100ksps 16-Bit ADC
Single 5V, ±10V Inputs
22 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
For more information www.linear.com/LTC1605-1
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com/LTC1605-1
160512fa
LT 0715 REV A • PRINTED IN THE USA
LINEAR TECHNOLOGY CORPORATION 1999
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湘ICP备2023018690号
