Datasheet

GAIN AND OFFSET ADJUST
Connections Using Potentiometers
OUTPUT VOLTAGE RANGE CONNECTIONS
Using D/A Converters
10kW
3
4
6
±10VV
OUT
9.75kW
IDAC
0mA-2mA
» +2.5V
15kW
R
27kW
3
R
10kW
4
120W 180W
R
500W
1
R
500W
2
5
170W 250W
Internal
+10VReference
V
REFOUT
GainAdjust
BipolarOffsetAdjust
2
ACOM
DAC712
SBAS023A – SEPTEMBER 2000 – REVISED JULY 2009 ................................................................................................................................................. www.ti.com
Nominal values of GAIN and OFFSET occur when
the D/A converter outputs are at approximately half
scale, +5V.
GAIN and OFFSET adjust pins provide for trim using
external potentiometers. 15-turn potentiometers
provide sufficient resolution. Range of adjustment of
The DAC712 output amplifier is connected internally
these trims is at least ± 0.3% of Full-Scale Range; see
for the ± 10V bipolar (20V) output range. That is, the
Figure 13 .
bipolar offset resistor is connected to an internal
reference voltage and the 20V range resistor is
connected internally to V
OUT
. The DAC712 cannot be
connected for unipolar operation.
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
30 µ V to 50 µ V per LSB step.
(1) For no external adjustments, pins 4 and 6 are not connected. External Resistors R
1
to R
4
are standard ± 1% values. Range of adjustment
is at least ± 0.3% FSR.
Figure 13. Manual Offset and Gain Adjust Circuits
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