DAC712
SBAS023A–SEPTEMBER 2000–REVISED JULY 2009 ................................................................................................................................................. www.ti.com
GAIN AND OFFSET ADJUST
Nominal values of GAIN and OFFSET occur when
the D/A converter outputs are at approximately half
scale, +5V.
Connections Using Potentiometers
GAIN and OFFSET adjust pins provide for trim using
external potentiometers. 15-turn potentiometers
provide sufficient resolution. Range of adjustment of
these trims is at least ±0.3% of Full-Scale Range; see
Figure 13.
OUTPUT VOLTAGE RANGE CONNECTIONS
The DAC712 output amplifier is connected internally
for the ±10V bipolar (20V) output range. That is, the
bipolar offset resistor is connected to an internal
reference voltage and the 20V range resistor is
connected internally to VOUT. The DAC712 cannot be
connected for unipolar operation.
Using D/A Converters
The GAIN ADJUST and OFFSET ADJUST circuits of
the DAC712 have been arranged so that these points
may be easily driven by external D/A converters; see
Figure 14. 12-bit D/A converters provide an OFFSET
adjust resolution and a GAIN adjust resolution of
30µV to 50µV per LSB step.
Internal
+10V Reference
VREF OUT
5
R1
R2
500W
500W
170W
250W
120W
180W
Gain Adjust
6
4
Bipolar Offset Adjust
15kW
9.75kW
10kW
R3
R4
27kW
10kW
» +2.5V
3
±10V VOUT
IDAC
0mA-2mA
2
ACOM
(1) For no external adjustments, pins 4 and 6 are not connected. External Resistors R1 to R4 are standard ±1% values. Range of adjustment
is at least ±0.3% FSR.
Figure 13. Manual Offset and Gain Adjust Circuits
16
Submit Documentation Feedback
Copyright © 2000–2009, Texas Instruments Incorporated
Product Folder Link(s): DAC712
TI [ TEXAS INSTRUMENTS ]
