MCP6541-E/LT MICROCHIP [Microchip Technology], MCP6541-E/LT Datasheet - Page 15

• Manufacturer Part Number: MCP6541-E/LT
• Description: Push-Pull Output Sub-Microamp Comparators
• Manufacturer: MICROCHIP [Microchip Technology]

FIGURE 4-3:
comparators’ internal hysteresis eliminates
output chatter caused by input noise voltage.
4.2
The push-pull output is designed to be compatible with
CMOS and TTL logic, while the output transistors are
configured to give rail-to-rail output performance. They
are driven with circuitry that minimizes any switching
current (shoot-through current from supply-to-supply)
when the output is transitioned from high-to-low, or from
low-to-high (see Figures 2-15, 2-18, 2-32 through 2-36
for more information).
4.3
The MCP6543 is a single comparator with Chip Select
(CS). When CS is pulled high, the total current
consumption drops to 20 pA (typ.); 1 pA (typ.) flows
through the CS pin, 1 pA (typ.) flows through the out-
put pin and 18 pA (typ.) flows through the V
shown in
comparator output is put into a high-impedance state.
By pulling CS low, the comparator is enabled. If the CS
pin is left floating, the comparator will not operate
properly.
supply current response to a CS pulse.
The internal CS circuitry is designed to minimize
glitches when cycling the CS pin. This helps conserve
power, which is especially important in battery-powered
applications.
© 2006 Microchip Technology Inc.
-1
-2
-3
8
7
6
5
4
3
2
1
0
V
Push-Pull Output
MCP6543 Chip Select (CS)
DD
Figure 1-1
= 5.0V
V
Figure
OUT
1-1. When this happens, the
Time (100 ms/div)
shows the output voltage and
The MCP6541/2/3/4
Hysteresis
V
IN
–
DD
pin, as
25
20
15
10
5
0
-5
-10
-15
-20
-25
-30
MCP6541/1R/1U/2/3/4
4.4
Greater flexibility in selecting hysteresis (or input trip
points) is achieved by using external resistors.
Input offset voltage (V
(input-referred) low-high and high-low trip points. Input
hysteresis voltage (V
the same trip points. Hysteresis reduces output
chattering when one input is slowly moving past the
other and thus reduces dynamic supply current. It also
helps in systems where it is best not to cycle between
states too frequently (e.g., air conditioner thermostatic
control).
4.4.1
Figure 4-4
supply applications using just two resistors. The
resulting hysteresis diagram is shown in
FIGURE 4-4:
hysteresis for single-supply.
FIGURE 4-5:
Non-Inverting Circuit.
The trip points for Figures 4-4 and 4-5 are:
EQUATION 4-1:
V
V
V
V
V
V
TLH
THL
OH
DD
OL
SS
V
V
IN
= trip voltage from low to high
= trip voltage from high to low
SS
V
V THL
V TLH
Externally Set Hysteresis
High-to-Low
V
REF
OUT
shows a non-inverting circuit for single-
NON-INVERTING CIRCUIT
R
=
=
1
V REF 1
V REF 1
V
OS
HYST
THL
Non-inverting circuit with
Hysteresis Diagram for the
⎛
⎜
⎝
) is the center (average) of the
+
-
⎛
⎜
⎝
MCP654X
V
) is the difference between
+
+
TLH
V
------ -
R F
------ -
R F
R 1
DD
R 1
Low-to-High
⎞
⎟
⎠
⎞
⎟
⎠
R
–
–
F
V OH
V OL
DS21696E-page 15
⎛
⎜
⎝
⎛
⎜
⎝
Figure
V
------ -
R F
R 1
------ -
R F
R 1
DD
⎞
⎟
⎠
⎞
⎟
⎠
V
OUT
4-5.
V
IN