TC1232_13 Datasheet, PDF (7/20 Pages) Microchip Technology – Microprocessor Monitor

4.0 OPERATIONAL DESCRIPTION
4.1 Power Monitor
The TC1232 provides the function of warning the
processor of a power failure. When V_CC is detected as
being below the voltage levels defined by the TOL pin,
the TC1232’s comparator outputs the RST and RST
signals to a logic level that warns the system of an out-
of-tolerance power supply. The RST and RST signals
switch at a threshold value of 4.5V if TOL is tied to V_CC,
and at a value of 4.75 volts if TOL is grounded. The
RST and RST signals are held active for a minimum of
250 ms to ensure that the power supply voltage has
been stabilized.
Figure 4-1 shows the V_CC fall time.
Figure 4-2 shows the V_CC rise time.
Figure 4-3 shows the time from when the voltage trip
point is detected to the reset output pin going active.
Figure 4-4 shows the time from when the voltage trip
point is exited to the reset output pin going inactive.
V_CC
t_F
+4.75V
+4.25V
FIGURE 4-1:
Power-Down Slew Rate.
t_R
+4.75V
+4.25V
V_CC = 5V
TC1232
+4.5V (5% Trip Point)
+4.25V (10% Trip Point)
RST
RST
t_RPD
V_OH
V_OL
V_CC SLEW RATE = 1.66 mV/µs (0.5V/300 µs)
FIGURE 4-3:
V_CC Detect Reset Output
Delay (Power-Down).
4.6V (5% Trip Point)
4.5V(10% Trip Point)
V_CC
RST
RST
t_RPU
V_OH
V_OL
FIGURE 4-4:
V_CC Detect Reset Output
Delay (Power-Up).
V_CC
FIGURE 4-2:
Power-up Slew Rate.
 2002-2012 Microchip Technology Inc.
Preliminary
DS21370D-page 7