COMA

BASE

OUT

C2

SCLK

C3

SDI

C1

VD

ERRLVL

CSB

VA

COMD

40

µC

Sensor

SPI

IN

HART Modulator

LDO

I n d u s t r i a l 4 - 2 0 m A T r a n s m i t t e r

0-24 mA Loop

+

-

LOOP

SUPPLY

LOOP

RECEIVER

80k

ÐÂ DAC

16

DAC161S997

LOOP+

LOOP-

ERRB

+

-

INT

SDO

NC

VD

Internal

Reference

DAC161S997

SNAS621 – JUNE 2013

www.ti.com

This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with

appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.

ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more

susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.

DEVICE INFORMATION

Functional Block Diagram

4-20 mA CURRENT LOOP TRANSMITTER

The DAC161S997 is a 16-bit DAC realized as a

∑Δ modulator. The DAC’s output is a current pulse train that is

filtered by the on-board low pass RC filter. The final output current is a multiplied copy of the filtered modulator

output. This architecture ensures an excellent linearity performance, while minimizing power consumption of the

device.

The DAC161S997 eases the design of robust, precise, long-term stable industrial systems by integrating all

precision elements on-chip. Only a few external components are needed to realize a low-power, high-precision

industrial 4 - 20 mA transmitter.

In case of a fault, or during initial power-up the DAC161S997 will output current in either upper or lower error

current band. The choice of band is user selectable via a device pin. The error current value is user

programmable via SPI.

2

Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: DAC161S997