ꢇ
ꢍ
ꢚ
ꢛ
ꢀ
ꢀ
ꢀ
SBAS314A − APRIL 2004 − REVISED SEPTEMBER 2004
ꢀ
ꢁ
ꢂ
ꢃ
ꢄ
ꢅ
ꢆ
ꢇ
ꢈ
ꢉ
ꢊ
ꢋ
ꢌ
ꢂ
ꢅ
ꢋ
ꢂ
ꢍ
ꢄ
ꢌ
ꢄ
ꢅ
ꢉ
ꢊ
ꢆ
ꢎ
ꢋ
ꢈ
ꢅ
ꢏ ꢐ ꢑ ꢅꢐ ꢑ
ꢘ ꢗꢊ ꢅ ꢄꢖ ꢊꢐ ꢙꢐꢑ
ꢒ
ꢄ
ꢅ
ꢓ
ꢀ
ꢂ
ꢎ
ꢓ
ꢉ
ꢈ
ꢈ
ꢐ
ꢊ
ꢍ
ꢄ
ꢔ
ꢔ
ꢐ
ꢑ
ꢐ
ꢈ
ꢅ
ꢄꢉ
ꢊ
ꢕ
ꢈ
ꢖ
ꢗ
FEATURES
DESCRIPTION
D
D
D
240SPS Data Rate with 4MHz Clock
20-Bit Effective Resolution
The ADS1222 is a 2-channel, 24-bit, delta-sigma ana-
log-to-digital (A/D) converter. It offers excellent perfor-
mance and low power in a TSSOP-14 package. The
ADS1222 is well-suited for demanding, high-resolution
measurements, especially in portable systems and oth-
er space-saving and power-constrained applications.
Input Multiplexer with Two Differential
Channels
D
D
D
D
D
D
D
D
D
Pin-Selectable, High-Impedance Input Buffer
5V Differential Input Range
A delta-sigma modulator and digital filter form the basis
of the A/D converter. The analog modulator has a 5V
differential input range. An input multiplexer (mux) is
used to select between two separate differential input
channels. A buffer can be selected to increase the input
impedance of the measurement.
0.0003% INL (typ), 0.0015% INL (max)
Self-Calibrating
Simple 2-Wire Serial Interface
On-Chip Temperature Sensor
Single Conversions with Standby Mode
Low Current Consumption: 300µA
Analog Supply: 2.7V to 5.5V
A simple, 2-wire serial interface provides all the
necessary control. Data retrieval, self-calibration, and
Standby mode are handled with a few simple
waveforms. When only single conversions are needed,
the ADS1222 can be quickly shut down (Standby mode)
while idle between measurements to dramatically
reduce the overall power consumption. Multiple
ADS1222s can be connected together to create a
synchronously sampling multichannel measurement
system. The ADS1222 is designed to easily connect to
microcontrollers, such as the MSP430.
APPLICATIONS
D
D
D
D
Hand-Held Instrumentation
Portable Medical Equipment
Industrial Process Control
Weigh Scales
The ADS1222 supports 2.7V to 5.5V supplies. Power
is typically less than 1mW in 3V operation and less than
1µW during Standby mode.
TEMPEN
VDD
VREFP VREFN
CLK
AINP1
AINN1
Digital Filter
and
Serial Interface
SCLK
∆Σ
Modulator
Mux
Buffer
DRDY/DOUT
AINP2
AINN2
MUX
BUFEN
GND
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.
All trademarks are the property of their respective owners.
ꢜꢝ ꢞ ꢍꢟ ꢎ ꢠꢕ ꢞꢡ ꢍ ꢇꢠꢇ ꢄꢈ ꢔꢋ ꢑ ꢢꢉ ꢅꢄꢋꢈ ꢄꢣ ꢤꢗ ꢑ ꢑ ꢐꢈꢅ ꢉꢣ ꢋꢔ ꢖꢗꢥ ꢊꢄꢤ ꢉꢅꢄ ꢋꢈ ꢦꢉ ꢅꢐꢧ ꢜꢑ ꢋꢦꢗ ꢤꢅꢣ
ꢤ ꢋꢈ ꢔꢋꢑ ꢢ ꢅꢋ ꢣ ꢖꢐ ꢤ ꢄ ꢔꢄ ꢤ ꢉ ꢅꢄ ꢋꢈꢣ ꢖ ꢐꢑ ꢅꢓꢐ ꢅꢐ ꢑ ꢢꢣ ꢋꢔ ꢠꢐꢙ ꢉꢣ ꢕꢈꢣ ꢅꢑ ꢗꢢ ꢐꢈꢅ ꢣ ꢣꢅ ꢉꢈꢦ ꢉꢑ ꢦ ꢒ ꢉꢑ ꢑ ꢉ ꢈꢅꢨꢧ
ꢜꢑ ꢋ ꢦꢗꢤ ꢅ ꢄꢋ ꢈ ꢖꢑ ꢋ ꢤ ꢐ ꢣ ꢣ ꢄꢈ ꢌ ꢦꢋ ꢐ ꢣ ꢈꢋꢅ ꢈꢐ ꢤꢐ ꢣꢣ ꢉꢑ ꢄꢊ ꢨ ꢄꢈꢤ ꢊꢗꢦ ꢐ ꢅꢐ ꢣꢅꢄ ꢈꢌ ꢋꢔ ꢉꢊ ꢊ ꢖꢉ ꢑ ꢉꢢ ꢐꢅꢐ ꢑ ꢣꢧ
Copyright 2004, Texas Instruments Incorporated
www.ti.com