Burr Brown Products
from Texas Instruments
ADS1232
ADS1234
SBAS350 – JUNE 2005
Ultra Low-Noise, 24-Bit Analog-to-Digital Converter
FEATURES
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Up to 23.5 Effective Bits
RMS Noise:
– 17nV at 10Hz
– 44nV at 80Hz
On-Board Low Noise Gain-Amp
19.2-Bit Noise-Free Resolution at Gain = 64
Simultaneous 50Hz and 60Hz Rejection:
– Internal Clock: 110 dB
– External Clock: 130 dB
±1%
Low-Drift On-Board Oscillator
Selectable Gains of 1, 2, 64, and 128
Selectable 10/80SPS Conversion Rates
2-Channel Differential Input with Built-In Temp
sensor (ADS1232)
4-Channel Differential Input (ADS1234)
External Reference up to AVDD
Simple Serial Digital Interface
Supply Range: 2.7V to 5.3V
–40°C to +105°C Temperature Range
DESCRIPTION
The ADS1232 and ADS1234 are precision
analog-to-digital (A/D) converters featuring true 23.5
effective-bit performance and exceptional ease of
use. Selectable gains of 1, 2, 64, or 128 allow
full-scale differential input ranges of
±2.5V
to
±19.5mV
with a +5V reference. While the ADS1232
offers a two-channel differential input and a built-in
temperature sensor, the ADS1234 features a
four-channel differential input multiplexer. A very
low-noise Gain-Amp features low differential input
current
to
minimize
errors
when
using
high-impedance transducers. An on-board oscillator
is provided for excellent 50Hz and 60Hz rejection
without an external clock source. The devices also
feature a low current driver to accommodate an
external crystal; they also accept external clock
sources for all applications.
All of the features of the ADS1232/ADS1234 are
hard-wire selected, without software programming.
Data is accessed over a simple serial interface
compatible with popular microcontrollers such as the
MSP430. The ADS1232 is available in the 24-pin
TSSOP package, and the ADS1234 is available in
the 28-pin TSSOP.
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APPLICATIONS
Weigh Scales
Strain Gauges
Bridge Sensors
Industrial Process Control
AVDD
CAP
REFP REFN
DVDD
GAIN [1:0]
AINP1
AINN1
AINP2
AINN2
AINP3
AINN3
AINP4
AINN4
A = 1, 2, 64,
128
Input
Mux
∆Σ
ADC
PDWN
DRDY/DOUT
SCLK
PGA
Internal Oscillator
External Oscillator
SPEED
A1/TEMP
(1)
A0
ADS1234
Only
AGND
CAP XTAL1/CLKIN XTAL2 DGND
NOTE: (1) A1 for ADS1234, TEMP for ADS1232.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCT PREVIEW information concerns products in the forma-
tive or design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the
right to change or discontinue these products without notice.
Copyright © 2005, Texas Instruments Incorporated
PRODUCT PREVIEW
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ADS1232
ADS1234
www.ti.com
SBAS350 – JUNE 2005
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated
circuits be handled with appropriate precautions. Failure to observe proper handling and installation
procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision
integrated circuits may be more susceptible to damage because very small parametric changes could
cause the device not to meet its published specifications.
ORDERING INFORMATION
(1)
PRODUCT
PACKAGE-LEAD
PACKAGE
DESIGNATOR
PW
PW
SPECIFIED
TEMPERATURE
RANGE
–40°C to 105°C
–40°C to 105°C
PACKAGE
MARKING
ADS1232
ADS1234
ORDERING
NUMBER
ADS1232IPWT
ADS1232IPWR
ADS1234IPWT
ADS1234IPWR
TRANSPORT MEDIA,
QUANTITY
Tape and Reel, 250
Tape and Reel, 2500
Tape and Reel, 250
Tape and Reel, 2500
ADS1232
ADS1234
(1)
TSSOP-24
TSSOP-28
For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
website at www.ti.com.
PRODUCT PREVIEW
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted)
AVDD to AGND
DVDD to DGND
AGND to DGND
Input Current
Input Current
Analog Input Voltage to AGND
Digital Input Voltage to DGND
Maximum Junction Temperature
Operating Temperature Range
Storage Temperature Range
Lead Temperature (soldering, 10s)
(1)
(1)
ADS1232, ADS1234
–0.3 to +6
–0.3 to +6
–0.3 to +0.3
100, Momentary
10, Continuous
–0.3 to AVDD + 0.3
–0.3 to DVDD + 0.3
+150
–40 to +105
–60 to +150
+300
UNIT
V
V
V
mA
mA
V
V
°C
°C
°C
°C
Stresses beyond those listed under
Absolute Maximum Ratings
may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under
Recommended Operating
Conditions
is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
2
ADS1232
ADS1234
www.ti.com
SBAS350 – JUNE 2005
ELECTRICAL CHARACTERISTICS: V
REF
= +5V
All specifications T
A
= –40°C to +105°C, AVDD = DVDD = VREFP = +5V, VREFN = AGND, Internal Oscillator, SPEED =
Low, Gain = 64 (unless otherwise specified).
ADS1232, ADS1234
PARAMETER
Analog Inputs
Full-Scale Input Voltage
(AIN
P
- AIN
N
)
Common-mode Input Range
AINxP or AINxN
with respect to GND, Gain = 1
Gain = 64, 128
Differential Input Current
System Performance
Resolution
No missing codes
Internal Oscillator, SPEED = High
Conversion Rate
Internal Oscillator, SPEED = Low
External Oscillator, SPEED = High
External Oscillator, SPEED = Low
Digital Filter Settling Time
Full Settling
Differential input, End point fit
Gain = 1, 2
Differential input, End point fit
Gain = 64, 128
Gain = 1
Gain = 64
Gain = 1
Gain = 64
Gain = 1
Gain = 64
Gain = 1
Gain = 64
Internal oscillator, 50Hz and 60Hz
Normal-mode
Rejection
(4)
External oscillator,
50Hz and 60Hz,
±1Hz
at DC, Gain = 1,
∆VDD
= 1V
at DC, Gain = 64,
∆VDD
= 0.1V
at DC, Gain = 1,
∆VDD
= 1V
at DC, Gain = 64,
∆VDD
= 0.1V
100
120
TBD
TBD
TBD
TBD
24
TBD
TBD
80
10
f
CLK
/ 61440
f
CLK
/ 491520
4
±0.0002
±0.0010
±0.2
±2
1
15
0.001
0.001
0.5
±4
110
130
100
75
See Noise Performance Tables
100
85
dB
dB
TBD
TBD
±0.0015
TBD
TBD
TBD
TBD
TBD
Bits
SPS
SPS
SPS
Conversions
% of FSR
(1)
% of FSR
ppm of FS
ppm of FS
µV/°C
nV/°C
%
%
ppm/°C
ppm/°C
dB
dB
dB
dB
SPS
Gain = 1, 2
Gain = 64, 128
AGND – 0.1
(0.5)AVDD – 1
500
50
±0.5V
REF
/Gain
AVDD + 0.1
(0.5)AVDD + 1
V
V
V
nA
nA
CONDITIONS
MIN
TYP
MAX
UNIT
Integral Non-Linearity (INL)
Input Offset Error
(2)
Input Offset Error Drift
Gain Error
(3)
Gain Error Drift
Common-mode Rejection
Input-Referred Noise
Power-Supply Rejection
Voltage Reference Input
Voltage Reference Input
(V
REF
)
Negative Reference Input
(VREFN)
Positive Reference Input
(VREFP)
Voltage Reference
Input Current
(1)
(2)
(3)
(4)
V
REF
= VREFP - VREFN
1
AGND – 0.1
VREFN + 1.0
AVDD AVDD + 0.1V
VREFP – 1.0
AVDD + 0.1
50
V
V
V
nA
FSR = full scale range = V
REF
/Gain
Offset calibration can minimize these errors to the level of noise at any temperature.
Gain errors are calibrated at the factory (AVDD = +5V, all gains, T
A
= +25°C).
Specification is assured by the combination of design and final production test.
3
PRODUCT PREVIEW
ADS1232
ADS1234
www.ti.com
SBAS350 – JUNE 2005
ELECTRICAL CHARACTERISTICS: V
REF
= +5V (continued)
All specifications T
A
= –40°C to +105°C, AVDD = DVDD = VREFP = +5V, VREFN = AGND, Internal Oscillator, SPEED =
Low, Gain = 64 (unless otherwise specified).
ADS1232, ADS1234
PARAMETER
Digital
Logic Levels
V
IH
V
IL
V
OH
V
OL
Input Leakage
Power Supply
Power Supply Voltage
(AVDD, DVDD)
Normal mode, AVDD = 3V, Gain = 1, 2
Normal mode, AVDD = 3V,
Gain = 64, 128
2.7
600
1500
700
1600
0.1
0.1
90
90
110
110
50
0.1
2.1
4
4.8
8.6
TBD
TBD
5.3
TBD
TBD
TBD
TBD
TBD
TBD
TBD
TBD
TBD
TBD
TBD
TBD
TBD
TBD
TBD
TBD
TBD
TBD
V
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
µA
mW
mW
mW
mW
mW
mW
I
OH
= 1mA
I
OL
= 1mA
0 < V
IN
< DVDD
0.6 DVDD
DGND
DVDD – 0.4
0.2 DVDD
±10
DVDD + 0.1
0.3 DVDD
V
V
V
V
µA
CONDITIONS
MIN
TYP
MAX
UNIT
PRODUCT PREVIEW
Analog Supply Current
Normal mode, AVDD = 5V, Gain = 1, 2
Normal mode, AVDD = 5V,
Gain = 64, 128
Standby mode
Power-down
Normal mode, DVDD = 3V, Gain = 1, 2
Normal mode, DVDD = 3V,
Gain = 64, 128
Digital Supply Current
Normal mode, DVDD = 5V, Gain = 1, 2
Normal mode, DVDD = 5V,
Gain = 64, 128
Standby mode, SCLK = High
Power-down
Normal mode, AVDD = DVDD = 3V,
Gain = 1, 2
Normal mode, AVDD = DVDD = 5V,
Gain = 1, 2
Power Dissipation, Total
Normal mode, AVDD = DVDD = 3V,
Gain = 64, 128
Normal mode, AVDD = DVDD = 5V,
Gain = 64, 128
Standby
Power-down
4
ADS1232
ADS1234
www.ti.com
SBAS350 – JUNE 2005
DEVICE INFORMATION
DVDD
DVDD
DGND
XTAL1/CLKIN
XTAL2
DGND
DGND
TEMP
A0
CAP
CAP
AINP1
AINN1
1
2
3
4
5
6
ADS1232
7
8
9
10
11
12
18
17
16
15
14
13
AVDD
AGND
REFP
REFN
AINP2
AINN2
A0
CAP
CAP
AINP1
AINN1
AINP3
AINN3
24
23
22
21
20
19
DRDY/DOUT
SCLK
PDWN
SPEED
GAIN1
GAIN0
DGND
XTAL1/CLKIN
XTAL2
DGND
DGND
A1
1
2
3
4
5
6
7
ADS1234
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
DRDY/DOUT
SCLK
PDWN
SPEED
GAIN1
GAIN0
AVDD
AGND
REFP
REFN
AINP2
AINN2
AINP4
AINN4
5
PRODUCT PREVIEW
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