FEATURES

240SPS Data Rate with 4MHz Clock

20-Bit Effective Resolution

Input Multiplexer with Two Differential

Channels

Pin-Selectable, High-Impedance Input Buffer

±5V Differential Input Range

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

APPLICATIONS

Hand-Held Instrumentation

Portable Medical Equipment

Industrial Process Control

Weigh Scales

DESCRIPTION

The ADS1222 is a 2-channel, 24-bit, delta-sigma analog-

to-digital (A/D) converter. It offers excellent performance

and low power in a TSSOP-14 package. The

ADS1222 is well-suited for demanding, high-resolution

measurements, especially in portable systems and other

space-saving and power-constrained applications.

A delta-sigma (ΔΣ) 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.

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.

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.