Microchip Technology MCP6XXXDM-FLTR User Manual
ACTIVE FILTER DEMO BOARD KIT
USER’S GUIDE
© 2006 Microchip Technology Inc.
DS51614A-page 25
Chapter 4. Common Filter Modifications
4.1
INTRODUCTION
The modifications described in this chapter include:
• Power Supplies
• Filter Section Ordering for Noise and Headroom
• Combining Low-pass and High-pass Sections
• Higher Frequency Filters
• Using 8-Pin SOIC Op Amps
• Power Supplies
• Filter Section Ordering for Noise and Headroom
• Combining Low-pass and High-pass Sections
• Higher Frequency Filters
• Using 8-Pin SOIC Op Amps
4.2
POWER SUPPLIES
4.2.1
Dual Power Supplies
To implement dual supplies, change the V
DD
/2 Filter Section (see Figure 4-1) setup:
• The boards’ bypass capacitors (C1 and C3) need to be removed and replaced
- Connect one set from –VS (board GND) to GND (board VDD/2)
- Connect the other set from +VS (board VDD) to GND (board VDD/2).
- Connect the other set from +VS (board VDD) to GND (board VDD/2).
• Remove R1 and R2, and then replace R2 with a short
• Set JP1 to External V
• Set JP1 to External V
DD
/2 (EXT, as shown)
• Connect the Lab Power Supply
- Voltage +V
S
to the board’s V
DD
input (TP3)
- Voltage GND to the V
DD
/2 input (TP4)
- Voltage –V
S
to the board’s GND input (TP5)
FIGURE 4-1:
Setting up V
DD
/2 Filter Section for dual supplies.
Lab Power Supply
GND
+VS
–VS
Set JP1 to
These signals correspond
External (EXT)
to the pins of the
unpopulated P1 and J1
GND
V
IN
GND
GND
V
DD
/2
V
DD
GND
V
OUT
GND
GND
V
DD
/2
V
DD