
P
FEATURES
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
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
±
19.5mV with a +5V reference. While the ADS1232
offers a two-channel differential input and a built-in
temperature
sensor,
the
four-channel differential input multiplexer. A very
low-noise Gain-Amp features low differential input
current
to
minimize
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.
APPLICATIONS
Weigh Scales
Strain Gauges
Bridge Sensors
Industrial Process Control
Input
Mux
Σ
ADC
REFP REFN
PGA
A = 1, 2, 64,
128
CAP
DVDD
DGND
AGND
A1/TEMP
(1)
A0
NOTE: (1) A1 for ADS1234, TEMP for ADS1232.
AINP1
AINN1
AINP2
AINN2
AINP3
AINN3
AINP4
AINN4
ADS1234
Only
SCLK
SPEED
DRDY/DOUT
PDWN
GAIN [1:0]
AVDD
CAP
External Oscillator
Internal Oscillator
XTAL1/CLKIN XTAL2
ADS1232
ADS1234
SBAS350–JUNE 2005
Ultra Low-Noise, 24-Bit Analog-to-Digital Converter
and
ADS1234
are
precision
ranges
of
±
2.5V
to
ADS1234
features
a
errors
when
using
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.
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