TC1275_07 Datasheet, PDF (4/12 Pages) Microchip Technology – 3-Pin Reset Monitors for 3.3V Systems

TC1275/TC1276/TC1277
3.0 APPLICATIONS INFORMATION
3.1 Operation – Power Monitor
The TC1275/TC1276/TC1277 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 200 ms after
the power supply has reached the selected tolerance.
This allows the power supply and microprocessor to
stabilize before RESET is released.
V_CCTP(MIN)
t_R
V_CCTP(MAX)
V_CCTP
V_CC
RESET
t_RPU1
V_OH
FIGURE 3-1:
Timing Diagram – Power Up
(TC1275/TC1276).
V_CC
V_CCTP(MAX)
V_CCTP
t_F
V_CCTP(MIN)
V_CC
t_R
V_CCTP(MIN)
V_CCTP(MAX)
V_CCTP
t_RPU2
RESET
V_OL
FIGURE 3-3:
Timing Diagram –
Power Up (TC1277).
V_CC
V_CCTP(MAX)
V_CCTP
t_F
V_CCTP(MIN)
t_RPD2
RESET
V_OH
RESET SLEWS WITH V_CC
FIGURE 3-4:
Timing Diagram –
Power Down (TC1277).
RESET
t_RPD1
V_OL
FIGURE 3-2:
Timing Diagram – Power
Down (TC1275/TC1276).
DS21383C-page 4
© 2007 Microchip Technology Inc.