Datasheet

MCP40D17/18/19
DS22152B-page 50 © 2009 Microchip Technology Inc.
8.2 Operational Amplifier
Applications
Figure 8-3 and Figure 8-4 illustrate typical amplifier
circuits that could replace fixed resistors with the
MCP40D17/18/19 to achieve digitally-adjustable
analog solutions.
FIGURE 8-3: Trimming Offset and Gain in
a Non-Inverting Amplifier.
FIGURE 8-4: Programmable Filter.
Op Amp
V
IN
V
OUT
‚
+
R
1
B
A
V
DD
W
R
3
MCP6291
MCP40D17
MCP40D18
Op Amp
V
IN
V
OUT
A
B
W
+
‚
R
1
B
A
V
DD
W
R
4
f
c
1
2
π R
Eq
C ⋅⋅
-----------------------------=
R
Eq
R
1
R
AB
R
WB
–+()R
2
R
WB
+()R
w
+
||
=
Thevenin
Equivalent
MCP6021
MCP40D18
MCP40D18