MCP6021 Microchip Technology, MCP6021 Datasheet - Page 16

• Manufacturer Part Number: MCP6021
• Description: Rail-to-Rail Input/Output, 10 MHz Op Amps
• Manufacturer: Microchip Technology

MCP6021/1R/2/3/4
Separate digital from analog, low speed from high
speed and low power from high power. This will reduce
interference.
Keep sensitive traces short and straight. Separating
them from interfering components and traces. This is
especially important for high-frequency (low rise-time)
signals.
Sometimes it helps to place guard traces next to victim
traces. They should be on both sides of the victim
trace, and as close as possible. Connect the guard
trace to ground plane at both ends, and in the middle
for long traces.
Use coax cables (or low inductance wiring) to route
signal and power to and from the PCB.
4.11
4.11.1
Figure 4-11 shows a third-order Butterworth filter that
can be used as an A/D converter driver. It has a band-
width of 20 kHz and a reasonable step response. It will
work well for conversion rates of 80 ksps and greater (it
has 29 dB attenuation at 60 kHz).
FIGURE 4-11:
anti-aliasing filter with a 20 kHz cutoff frequency.
This filter can easily be adjusted to another bandwidth
by multiplying all capacitors by the same factor.
Alternatively, the resistors can all be scaled by another
common factor to adjust the bandwidth.
DS21685C-page 16
8.45 k
1.2 nF
Typical Applications
A/D CONVERTER DRIVER AND
ANTI-ALIASING FILTER
14.7 k
A/D converter driver and
33.2 k
100 pF
1.0 nF
MCP602X
4.11.2
Figure 4-12 shows the MCP6021 op amp used as a
transimpedance amplifier in a photo detector circuit.
The photo detector looks like a capacitive current
source, so the 100 k resistor gains the input signal to
a reasonable level. The 5.6 pF capacitor stabilizes this
circuit and produces a flat frequency response with a
bandwidth of 370 kHz.
FIGURE 4-12:
for an Optical Detector.
OPTICAL DETECTOR AMPLIFIER
Detector
Photo
100 pF
Transimpedance Amplifier
© 2006 Microchip Technology Inc.
V
DD
/2
100 k
5.6 pF
MCP6021