DAC1208 datasheet(14/18 Pages) NSC

14 / 18 page

Application Hints (Continued)

221 Zero and Full-Scale Adjustments

To calibrate the bipolar output circuit three adjustments are

required The first step is to set all of the digital inputs LOW

(to force IOUT1 to 0) then null the VOS of amplifier 1 by

setting the voltage at its inverting input (pin 2) to zero volts

Next with a code of all zeros still applied adjust ‘‘bfull-

scale adjust’’ the reference voltage for VOUTe g

lVREF id-

eal

l The polarity of the output voltage at this time will be

opposite that of the applied reference Finally set all of the

digital inputs HIGH and adjust ‘‘afull-scale adjust’’ for

VOUT e VREF

2047

2048

The polarity of the output will be the same as that of the

reference voltage

30 APPLICATION IDEAS

In this section the digital input word is represented by the

letter D and is equal to the decimal equivalent of the 12-bit

binary input Hence D can be any integer value between 0

and 4095

Composite Amplifier for Good DC Characteristics and Fast Output Response

Combines the low VOS

low VOS drift and low

bias current of the

LM11 with the fast

response of the LF351

Settling time

8 mS

for a zero to full-

scale transition

High Voltage Power DAC

VOUT e

VREFD

4096

1 a

RFb

(

TLH5690 – 17

DAC1208 Datasheet(PDF) 14 Page - National Semiconductor (TI)