DAC8822_07 Datasheet, PDF (17/24 Pages) Burr-Brown (TI) – 16-Bit, Dual, Parallel Input, Multiplying Digital-to-Analog Converter

DAC8822
www.ti.com
SBAS390A – DECEMBER 2006 – REVISED MARCH 2007
APPLICATION INFORMATION (continued)
BIPOLAR OUTPUT CIRCUIT
The DAC8822, as a 4-quadrant multiplying DAC, can be used to generate a bipolar output. The polarity of the
full-scale output (I_OUT) is the inverse of the input reference voltage at V_REF.
Using a dual op amp, such as the OPA2277, full 4-quadrant operation can be achieved with minimal
components. Figure 43 demonstrates a ±10V_OUT circuit with a fixed +10V reference. The output voltage is
shown in Equation 2:
ǒ Ǔ V_OUT +
D
32768
*1
V _REF
(2)
V_REF
U1
OPA2277
DGND
DAC8822
V_DD
R₁A
R_COMA
R₁A
V_REFA
R₂A
R_OFSA
R_FBA
R_OFSA R_FBA
D0
D15
WR
A0
A1
RS
LDAC
RSTSEL
Parallel
Bus
Interface
Input A
Register
Control
Logic
DAC A
Register
DAC A
C₁
I_OUTA
AGNDA
U2
OPA2277
V_OUT
Figure 43. Bipolar Output Circuit for Channel A
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