MCP4725 Microchip Technology, MCP4725 Datasheet - Page 31

• Manufacturer Part Number: MCP4725
• Description: 12-Bit Digital-to-Analog Converter
• Manufacturer: Microchip Technology

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8.5.4
Bipolar operation is achievable using the MCP4725 by
using an external operational amplifier (op amp). This
allows a general purpose DAC, with its cost and
availability advantages, to meet almost any desired
output voltage range, power and noise performance.
EXAMPLE 8-3:
© 2007 Microchip Technology Inc.
BIPOLAR OPERATION
1
2
3
V
V
V
0.1 µF
MCP4725
OUT
SS
DD
V
Digitally-Controlled Bipolar Voltage Source.
V
V
OUT
SCL
SDA
IN+
O
A0
=
10 µF
=
=
6
5
4
V
V
V
------------------- -
IN+
R
DD
OUT
3
⎛
⎝
+
1
-------
2
D
R
R
12
+
V
4
4
DD
R
----- -
R
2
1
⎞
⎠
R R
–
V
V
DD
DD
⎛
⎝
R
----- -
R
2
1
⎞
⎠
where D = DAC Input Code (0 – 4095)
V
(MASTER)
OUT
To MCU
Example 8-3
configuration. R
while R
offset. Note that R4 can be tied to V
of V
to V
desired.
R
DD
SS
3
R
, if a higher offset is desired. Note that a pull-up
could be used, instead of R
4
3
V
and R
DD
illustrates a simple bipolar voltage source
1
4
R
and R
shift the DAC's output to a selected
1
0.1 µF
V
IN
+
2
allow the gain to be selected,
V
V
R
CC
CC
2
MCP4725
+
–
4
DD
, if a higher offset is
DS22039C-page 31
V
(= V
O
REF
) instead