Microchip Technology MCP6XXXDM-FLTR User Manual
Building the Filter Supplied in the Kit
© 2006 Microchip Technology Inc.
DS51614A-page 21
Figure 3-3 is a picture of the fully assembled filter shown in Figure 3-1. Note that the
board on the left (V
board on the left (V
DD
/2 Filter Section) provides an easy way to connect the input signal
source and power supply to the filter. JP1 on this board may be connected to INT or
EXT in this case.
EXT in this case.
FIGURE 3-3:
Picture of the Filter Supported by the Active Filter Demo Board
Kit.
3.4
TESTING THE FILTER
3.4.1
DC Bias
Figure 3-4 shows the most important DC bias voltages to check.
FIGURE 3-4:
Points to check DC Bias.
3.4.2
Response Variability
Resistors and capacitors with tighter tolerances will reduce the variability of the filters
response over process and, sometimes, temperature. Figure 3-5 shows the simulated
±3.3 sigma gain error (in dB) for each frequency (based on a uniform random
distribution). Figure 3-6 shows a histogram of the pass-band frequency (f
response over process and, sometimes, temperature. Figure 3-5 shows the simulated
±3.3 sigma gain error (in dB) for each frequency (based on a uniform random
distribution). Figure 3-6 shows a histogram of the pass-band frequency (f
P
) from the
same simulation.
GND
V
IN
GND
GND
V
DD
/2
V
DD
GND
V
OUT
GND
GND
V
DD
/2
V
DD
Test Supply Voltages Here
Test V
OUT
Here