Datasheet

© 2012 Microchip Technology Inc. DS25124A-page 25
MCP6V11/1U
4.4.3 OFFSET VOLTAGE CORRECTION
Figure 4-13 shows MCP6V11 (U
2
) correcting the input
offset voltage of another op amp (U
1
). R
2
and C
2
integrate the offset error seen at U
1
’s input; the
integration needs to be slow enough to be stable (with
the feedback provided by R
1
and R
3
). R
4
and R
5
attenuate the integrator’s output; this shifts the
integrator pole down in frequency.
FIGURE 4-13: Offset Correction.
4.4.4 PRECISION COMPARATOR
Use high gain before a comparator to improve the
latter’s performance. Do not use MCP6V11/1U as a
comparator by itself; the V
OS
correction circuitry does
not operate properly without a feedback loop.
FIGURE 4-14: Precision Comparator.
U
1
MCP6XXX
C
2
R
2
R
1
R
3
V
DD
/2
R
4
V
IN
V
OUT
R
2
V
DD
/2
R
5
U
2
MCP6V11
V
IN
R
3
R
2
V
DD
/2
V
OUT
R
5
R
4
R
1
U
1
MCP6V11
U
2
MCP6541