Datasheet

PIN
NAME FUNCTION
MAX690A/MAX692A
MAX802L/MAX802M
MAX805L
1 1 V
OUT
Supply Output for CMOS RAM. When V
CC
is above the reset threshold,
V
OUT
connects to V
CC
through a P-channel MOSFET switch. When
V
CC
is below the reset threshold, the higher of V
CC
or V
BATT
will be
connected to V
OUT
.
2 2 V
CC
+5V Supply Input
3 3 GND Ground
4 4 PFI
Power-Fail Comparator Input. When PFI is less than 1.25V, PFO goes
low. Connect PFI to GND or V
CC
when not used.
5 5
PFO
Power-Fail Output. When PFI is less than 1.25V, PFO goes low;
otherwise PFO stays high.
6 6 WDI
Watchdog Input. If WDI remains high or low for 1.6sec, the internal
watchdog timer runs out and reset is triggered. If WDI is left oating
or connected to a high-impedance three-state buffer, the watchdog
feature is disabled. The internal watchdog timer clears whenever reset is
asserted, WDI is three-stated, or WDI sees a rising or falling edge.
7 7
RESET
Reset Output. Whenever RESET is triggered, it pulses low for 200ms.
It stays low when V
CC
is below the reset threshold (4.65V in the
MAX690A/MAX802L and 4.4V in the MAX692A/MAX802M) and remains
low for 200ms after V
CC
rises above the reset threshold. A watchdog
timeout also triggers RESET.
— — RESET
Active-High Reset Output is the inverse of RESET. When RESET is
asserted, the RESET output voltage = V
CC
or V
BATT
, whichever is
higher.
8 8 V
BATT
Backup-Battery Input. When V
CC
falls below the reset threshold, V
BATT
will be switched to V
OUT
if V
BATT
is 20mV greater than V
CC
. When V
CC
rises to 20mV above V
BATT
, V
OUT
will be reconnected to V
CC
. The
40mV hysteresis prevents repeated switching if V
CC
falls slowly.
MAX690A/MAX692A/
MAX802L/MAX802M/
MAX805L
Microprocessor Supervisory Circuits
www.maximintegrated.com
Maxim Integrated │ 5
Pin Description