MCP6273-E/SL Microchip Technology, MCP6273-E/SL Datasheet - Page 15

• Manufacturer Part Number: MCP6273-E/SL
• Description: 170 uA, 2 MHz Rail-to-Rail Op Amp
• Manufacturer: Microchip Technology

3.8.3.6
Figure 3-15 is a second-order Sallen-Key low-pass
filter with chip select. Use the Filterlab
Microchip to determine the R and C values for the op
amp A’s second-order filter. Op amp B can be used to
add a pole-zero pair using C
FIGURE 3-15:
Low-Pass Filter with an Extra Pole-Zero Pair and
a Chip Select.
 2004 Microchip Technology Inc.
V
IN
R
4
R
Second-Order Sallen-Key with an
Extra Pole-Zero Pair
R
3
C
2
1
C
Second Order Sallen-Key
R
2
A
1
3
and R
MCP6275
R
CS
5
5
.
®
software from
C
B
3
V
OUT
3.8.3.7
The low-pass filter shown in Figure 3-16 does not
require external capacitors and uses only three exter-
nal resistors, while the op amp’s GBWP sets the corner
frequency. R
is used to set the Q. To avoid gain-peaking in the
frequency response, Q needs to be low (lower values
need to be selected for R
bandwidth varies greatly over temperature and
process. This configuration, however, provides a low-
cost solution for applications with high bandwidth.
FIGURE 3-16:
Low-Pass Filter with Chip Select Circuit.
V
V
REF
IN
R
2
MCP6271/2/3/4/5
1
Capacitorless Second Order
Low-Pass filter with Chip Select
and R
A
2
are used to set the circuit gain. R
MCP6275
Capacitorless Second-Order
R
3
CS
3
). Note that the amplifier
R
B
1
DS21810C-page 15
V
OUT
3