User manual

Building the Filter Supplied in the Kit
© 2006 Microchip Technology Inc. DS51614A-page 23
FIGURE 3-7: Frequency Response for All Outputs.
Figure 3-8 shows the step response of the filter in Figure 3-1. The output of U
2
(the
second op amp) shows the largest overshoot, so it limits the output voltage range of
the filter. The nominal overshoot is 6.1% (0.18V for a 3.0V step).
FIGURE 3-8: Step Response for All Outputs.
Many SPICE simulators support Monte Carlo simulations. Using this capability on your
design will help determine what tolerances are needed on your design. The same
results can be obtained by measuring many filters (i.e., 30 to 10,000), but at a greater
cost.
-80
-70
-60
-50
-40
-30
-20
-10
0
10 100 1,000
Frequency (Hz)
Gain (dB)
MCP601 Op Amps
Nominal Simulation
V
OUT
:
U
1
U
2
U
3
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
02468101214
Time (ms)
Section Output Voltages (V)
V
OUT
:
U
1
U
2
U
3
MCP601 Op Amps
Nominal Simulation
V
DD
= 5.0V
V
IN