MCP6002 Microchip Technology Inc., MCP6002 Datasheet - Page 11

• Manufacturer Part Number: MCP6002
• Description: 1 Mhz, Low-power Op Amp
• Manufacturer: Microchip Technology Inc.

FIGURE 4-6:
for Inverting Gain.
1.
2.
4.7
4.7.1
The rail-to-rail input and output capability of the
MCP6001/2/4 op amp is ideal for unity-gain buffer
applications. The low quiescent current and wide
bandwidth makes the device suitable for a buffer
configuration in an instrumentation amplifier circuit, as
shown in
© 2007 Microchip Technology Inc.
Non-inverting Gain and Unity-Gain Buffer:
a.
b.
Inverting Gain and Transimpedance Gain Ampli-
fiers (convert current to voltage, such as photo
detectors):
a.
b.
Connect the non-inverting pin (V
input with a wire that does not touch the
PCB surface.
Connect the guard ring to the inverting input
pin (V
common mode input voltage.
Connect the guard ring to the non-inverting
input pin (V
to the same reference voltage as the op
amp (e.g., V
Connect the inverting pin (V
with a wire that does not touch the PCB
surface.
Application Circuits
Figure
UNITY-GAIN BUFFER
IN
4-7.
–). This biases the guard ring to the
V
IN
IN
Guard Ring
DD
+). This biases the guard ring
Example Guard Ring Layout
-
/2 or ground).
V
IN
+
IN
–) to the input
IN
V
SS
+) to the
FIGURE 4-7:
with Unity-Gain Buffer Inputs.
4.7.2
The MCP6001/2/4 op amp’s low input bias current
makes it possible for the designer to use larger
resistors and smaller capacitors for active low-pass
filter
increases, the noise generated also increases.
Parasitic capacitances and the large value resistors
could also modify the frequency response. These
trade-offs need to be considered when selecting circuit
elements.
Usually, the op amp bandwidth is 100X the filter cutoff
frequency (or higher) for good performance. It is
possible to have the op amp bandwidth 10X higher than
the cutoff frequency, thus having a design that is more
sensitive to component tolerances.
Figure 4-8
100 kHz cutoff frequency and a gain of +1 V/V; the op
amp bandwidth is only 10X higher than the cutoff
frequency. The component values were selected using
Microchip’s FilterLab
FIGURE 4-8:
Low- Pass Filter.
MCP6001/1R/1U/2/4
V
V
V
IN2
IN1
IN
applications.
14.3 kΩ
V
shows a second-order Butterworth filter with
OUT
ACTIVE LOW-PASS FILTER
MCP6002
MCP6002
+
–
+
–
1/2
1/2
53.6 kΩ
33 pF
=
(
V
®
IN2
However,
software.
Instrumentation Amplifier
Active Second-Order
–
100 pF
V
R
R
2
IN1
2
)
•
R
MCP6002
V
+
–
–
+
MCP6001
as
1
R
----- -
R
REF
1
2
R
DS21733G-page 11
+
1
the
V
REF
R
R
1
2
= 20 kΩ
= 10 kΩ
resistance
V
V
OUT
OUT