MCP6546/6R/6U/7/8/9
4.9
Unused Comparators
4.10
4.10.1
Typical Applications
PRECISE COMPARATOR
An unused amplifier in a quad package (MCP6549)
should be configured as shown in
Figure 4-8.
This
circuit prevents the output from toggling and causing
crosstalk. It uses the minimum number of components
and draws minimal current (see
Figure 2-15
and
Figure 2-18).
錄 MCP6549
V
DD
Some applications require higher DC precision. An
easy way to solve this problem is to use an amplifier
(such as the MCP6041) to gain-up the input signal
before it reaches the comparator.
Figure 4-9
shows an
example of this approach.
V
DD
V
REF
MCP6041
V
DD
V
IN
R
1
R
2
鈥?/div>
+
V
PU
R
PU
V
REF
MCP6546
V
OUT
FIGURE 4-8:
Unused Comparators.
FIGURE 4-9:
Comparator.
4.10.2
Precise Inverting
WINDOWED COMPARATOR
Figure 4-10
shows one approach to designing a
windowed comparator. The wired-OR connection
produces a high output (logic 1) when the input voltage
is between V
RB
and V
RT
(where V
RT
> V
RB
).
V
PU
R
PU
V
OUT
V
IN
V
RT
1/2
MCP6547
V
RB
1/2
MCP6547
FIGURE 4-10:
Windowed Comparator.
DS21714E-page 16
漏
2006 Microchip Technology Inc.
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