PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
24-Bit
ANALOG-TO-DIGITAL CONVERTER
FEATURES
a71 24 BITS NO MISSING CODES
a71 SIMULTANEOUS 50Hz AND 60Hz REJECTION
(–90dB MINIMUM)
a71 0.0015% INL
a71 21 BITS EFFECTIVE RESOLUTION
(PGA = 1), 19 BITS (PGA = 128)
a71 PGA GAINS FROM 1 TO 128
a71 SINGLE-CYCLE SETTLING
a71 PROGRAMMABLE DATA OUTPUT RATES
a71 EXTERNAL DIFFERENTIAL REFERENCE
OF 0.1V TO 5V
a71 ON-CHIP CALIBRATION
a71 SPI™ COMPATIBLE
a71 2.7V TO 5.25V SUPPLY RANGE
a71 600µW POWER CONSUMPTION
a71 UP TO EIGHT INPUT CHANNELS
a71 UP TO EIGHT DATA I/O
DESCRIPTION
The ADS1242 and ADS1243 are precision, wide dynamic
range, delta-sigma, analog-to-digital (A/D) converters with
24-bit resolution operating from 2.7V to 5.25V supplies.
These delta-sigma, A/D converters provide up to 24 bits of no
missing code performance and effective resolution of 21 bits.
The input channels are multiplexed. Internal buffering can be
selected to provide a very high input impedance for direct
connection to transducers or low-level voltage signals. Burn-
out current sources are provided that allow for the detection
of an open or shorted sensor. An 8-bit digital-to-analog
converter (DAC) provides an offset correction with a range of
50% of the FSR (Full-Scale Range).
The Programmable Gain Amplifier (PGA) provides selectable
gains of 1 to 128 with an effective resolution of 19 bits at a gain
of 128. The A/D conversion is accomplished with a second-order
delta-sigma modulator and programmable FIR filter that pro-
vides a simultaneous 50Hz and 60Hz notch. The reference input
is differential and can be used for ratiometric conversion.
The serial interface is SPI compatible. Up to eight bits of data
I/O are also provided that can be used for input or output. The
ADS1242 and ADS1243 are designed for high-resolution
measurement applications in smart transmitters, industrial
process control, weight scales, chromatography, and portable
instrumentation.
APPLICATIONS
a71 INDUSTRIAL PROCESS CONTROL
a71 LIQUID/GAS CHROMATOGRAPHY
a71 BLOOD ANALYSIS
a71 SMART TRANSMITTERS
a71 PORTABLE INSTRUMENTATION
a71 WEIGHT SCALES
ADS1242
ADS1243
SBAS235B – DECEMBER 2001 – OCTOBER 2004
www.ti.com
Copyright © 2001-2004, Texas Instruments Incorporated
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.
®
AD
S1
24
3
®AD
S1
24
2
BUF PGA
A = 1:128
+
Clock Generator
Serial Interface
2nd-Order
Modulator
GND
V
DD
IN+
IN–
V
REF+
V
REF–
X
IN
X
OUT
PDWN DRDY
SCLK
D
IN
D
OUT
CS
MUX
A
IN
0/D0
A
IN
1/D1
A
IN
2/D2
A
IN
3/D3
A
IN
4/D4
A
IN
5/D5
A
IN
6/D6
A
IN
7/D7
Controller Registers
Digital
Filter
2µA
V
DD
Offset
DAC
GND
2µA
ADS1243
Only
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