MCP6001/2/4
This voltage rate of change is less than the MCP6001/2/4
slew rate of 0.6 V/µs. When the input voltage swings
below the voltage across C
1
, D
1
becomes reverse-
biased. This opens the feedback loop and rails the
amplifier. When the input voltage increases, the amplifier
recovers at its slew rate. Based on the rate of voltage
change shown in the above equation, it takes an
extended period of time to charge a 0.1 µF capacitor. The
capacitors need to be selected so that the circuit is not
limited by the amplifier slew rate. Therefore, the capaci-
tors should be less than 40 µF and a stabilizing resistor
(R
ISO
) needs to be properly selected. (Refer to
V
IN
1/2
MCP6002
–
+
D
1
R
ISO
V
C1
C
1
R
1
+ 1/2
MCP6002
–
Op Amp B
R
ISO
V
C2
C
2
+
MCP6001
–
Op Amp C
Sample
Switch
Clear
Switch
t
SAMP
V
OUT
Op Amp A
Sample Signal
t
CLEAR
Clear Signal
t
DETECT
CLK
FIGURE 4-8:
Peak Detector with Clear and Sample CMOS Analog Switches.
©
2005 Microchip Technology Inc.
DS21733F-page 11
MICROCHIP [ MICROCHIP TECHNOLOGY ]
