Datasheet

AD5780 Data Sheet
Rev. E | Page 24 of 28
Gain of Two Configuration (×2 Gain Mode)
Figure 52 shows an output amplifier configured for a gain of
two. The gain is set by the internal matched 6.8 kΩ resistors,
which are exactly twice the DAC resistance, having the effect
of removing an offset from the input bias current of the external
amplifier. In this configuration, the output spans from 2 × V
REFN
−
V
REFP
to V
REFP
. This configuration is used to generate a bipolar
output span from a single-ended reference input, with V
REFN
=
0 V. For this mode of operation, the RBUF bit of the control
register must be cleared to Logic 0.
A1
6.8kΩ 6.8kΩ
R1
10pF
R
FB
18-BIT
DAC
V
REFN
V
REFP
AD5780
AD8675,
ADA4898-1,
ADA4004-1
R
FB
INV
V
OUT
V
OUT
09649-050
Figure 52. Output Amplifier in Gain-of-Two Configuration