ADS1

217

8-Channel, 24-Bit

ANALOG-TO-DIGITAL CONVERTER

FEATURES

q 24 BITS NO MISSING CODES

q INL: 0.0012% of FSR (max)

q FULL-SCALE INPUT:

REF

q PGA FROM 1 TO 128

q 22 BITS EFFECTIVE RESOLUTION

(PGA = 1), 19 BITS (PGA = 128)

q SINGLE CYCLE SETTLING MODE

q PROGRAMMABLE DATA OUTPUT RATES

UP TO 1kHz

q ON-CHIP 1.25V/2.5V REFERENCE

q ON-CHIP CALIBRATION

q SPI COMPATIBLE

q POWER SUPPLY: 2.7V to 5.25V

q < 1mW POWER CONSUMPTION, V

DESCRIPTION

The ADS1217 is a precision, wide dynamic range, delta-

sigma, Analog-to-Digital (A/D) converter with 24-bit resolu-

tion operating from 2.7V to 5.25V supplies. The delta-sigma,

A/D converter provides up to 24 bits of no missing code

performance and effective resolution of 22 bits.

The eight 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.

Burnout 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 PGA (Programmable Gain Amplifier) 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 2nd-order,

delta-sigma modulator and programmable sinc filter. The

reference input is differential and can be used for ratiometric

measurements. The onboard current DACs operate indepen-

dently with the maximum current set by an external resistor.

The serial interface is SPI compatible. Eight bits of digital I/O

are also provided that can be used for input or output. The

ADS1217 is designed for high-resolution measurement appli-

cations in smart transmitters, industrial process control, weigh

scales, chromatography, and portable instrumentation.

APPLICATIONS

q INDUSTRIAL PROCESS CONTROL

q LIQUID/GAS CHROMATOGRAPHY

q BLOOD ANALYSIS

q SMART TRANSMITTERS

q PORTABLE INSTRUMENTATION

q WEIGH SCALES

q PRESSURE TRANSDUCERS

BUF

PGA

+

Voltage

Reference

Clock Generator

Registers

Serial Interface

2nd-Order

Modulator

RAM

Digital I/O

Interface

AGND

AV

DD

R

DAC

V

REFOUT

V

RCAP

V

X

IN

X

OUT

D7

BUFEN

...

D0

DGND

DV

DD

D

IN

SCLK

POL

D

OUT

CS

DRDY

PDWN

DYSNC

RESET

MUX

A

A

A

A

A

A

A

A

A

INCOM

IDAC1

Controller

Program-

mable

Digital

Filter

8-Bit

IDAC

IDAC2

8-Bit

IDAC

Offset

DAC

ADS1217

SBAS260B – MAY 2002 – REVISED OCTOBER 2004

www.ti.com

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.

Copyright © 2002-2004, 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.

All trademarks are the property of their respective owners.