MCP6241-E/OT MICROCHIP [Microchip Technology], MCP6241-E/OT Datasheet - Page 14

• Manufacturer Part Number: MCP6241-E/OT
• Description: 50 ?A, 550 kHz Rail-to-Rail Op Amp
• Manufacturer: MICROCHIP [Microchip Technology]

MCP6241/1R/1U/2/4
4.7.2
In analog circuit design, the PCB parasitic capacitance
can compromise the circuit behavior;
a typical scenario. If the input of an amplifier sees
parasitic capacitance of several picofarad (C
which includes the common mode capacitance of 6 pF,
typical) and large R
of the circuit will include a zero. This parasitic zero
introduces gain peaking and can cause circuit
instability.
FIGURE 4-9:
Capacitance at the Input.
One solution is to use smaller resistor values to push
the zero to a higher frequency. Another solution is to
compensate by introducing a pole at the point at which
the zero occurs. This can be done by adding C
parallel with the feedback resistor (R
selected so that the ratio C
of R
DS21882D-page 14
V
V
F
AC
DC
:R
G
.
COMPENSATING FOR THE
PARASITIC CAPACITANCE
C
R
PARA
G
F
and R
Effect of Parasitic
MCP624X
+
–
PARA
R
C
G
F
F
, the frequency response
:C
C
F
F
is equal to the ratio
=
F
Figure 4-9
). C
C
PARA
F
V
needs to be
OUT
•
R
------ -
R
shows
G
F
PARA
F
in
,
© 2008 Microchip Technology Inc.