2002-2012 Microchip Technology Inc. DS21451E-page 7
TC6501/2/3/4
5.0 APPLICATIONS
The TC6501 and TC6503 have open-drain outputs and
are, therefore, intended to interface as microcontroller
reset inputs. Moreover, the combination of these two
devices can be used to implement a temperature
window alarm by wire-ORing the outputs and using an
external pull-up resistor (see Figure 5-1).
FIGURE 5-1: Over and Under
Temperature Alarm.
The TC6502 can be used to control a DC fan. The fan
turns on when the sensed temperature rises above the
factory-set threshold and remains on until the
temperature falls below threshold minus the hysteresis
selected. An additional fail-safe measure could be
designed by using a second TC6502 with a higher
temperature threshold to alert the user of an impending
thermal shutdown, should the temperature continue to
rise (see Figure 5-2).
FIGURE 5-2: Fan Control with Over
Temperature Alert.
The TC6504, with its push-pull output, may be used in
a similar fashion to turn on a heater element at cold
temperatures (see Figure 5-3).
FIGURE 5-3: TC6504 As Heater
Thermostat.
HYST
V
CC
GNDGND HYST
T
UNDER
+5V
R
PULL-UP
100 k
GND
GND
V
CC
T
OVER
TC6501 TC6503
HYST
100 pF
Out of Range
100 pF
HYST
V
CC
GNDGND HYST
T
UNDER
GND
GND
V
CC
T
OVER
TC6501 TC6503
HYST
Temperature
GND
GND
100 pF
HYST
+5V
T
OVER
V
CC
TC6502PO65
GND GND
HYST
T
OVER
V
CC
TC6502PO45
Temperature
Fault
Fan Control
GND
GND
HYST
+5V
T
OVER
V
CC
TC6502PO65
GND GND
HYST
T
OVER
V
CC
TC6502PO45
GND
GND
HYST
+5V
T
OVER
V
CC
TC6502
GND GND
HYST
T
OVER
V
CC
TC6502
100 pF
Heater "On"
T
UNDER
T
UNDER
T
UNDER
+ 2°C
TC6504
+5V
12V
GND
GND HYST
V
CC
Heater
T
UNDER
100 pF
Temperature
Time
