TC1278_07 Datasheet, PDF (5/12 Pages) Microchip Technology – 3-Pin Reset Monitors for 5V Systems

3.0 APPLICATIONS INFORMATION
3.1 Operation – Power Monitor
The TC1278/TC1279 provide the function of detecting
out-of-tolerance power supply conditions and warning
a processor-based system of impending power failure.
When V_CC is detected as out-of-tolerance, the RESET
signal is asserted. On power-up, RESET is kept active
for approximately 350 ms after the power supply has
reached the selected tolerance. This allows the power
supply and microprocessor to stabilize before RESET
is released.
V_CC
RESET
4.00V
t_R
4.75V
V_CCTP
t_RPU1
V_OH
FIGURE 3-1:
Diagram.
TC1279 Power Up Timing
V_CC
4.75V
V_CCTP
t_F
4.00V
RESET
t_RPD1
TC1278/TC1279
V_CC
V_CCTP(MIN)
t_R
V_CCTP(MAX)
V_CCTP
t_RPU2
RESET
FIGURE 3-3:
Diagram.
V_OL
TC1278 Power-Up Timing
V_CC
4.74V
V_CCTP
t_F
4.00V
t_RPD2
RESET
V_OH
RESET SLEWS WITH V_CC
FIGURE 3-4:
TC1278 Power-Down
Timing Diagram.
V_OL
FIGURE 3-2:
TC1279 Power-Down
Timing Diagram.
© 2007 Microchip Technology Inc.
DS21384D-page 5