MAX6854/MAX6855/MAX6856/MAX6858/MAX6860–MAX6869
Nanopower µP Supervisory Circuits with
Manual Reset and Watchdog Timer
_______________________________________________________________________________________ 9
MAX6867/MAX6868/MAX6869 Pin Description
PIN
MAX6867/
MAX6869
MAX6868
NAME FUNCTION
11WDI
Watchdog Input. If WDI remains high or low for longer than the watchdog timeout
period, the internal watchdog timer expires, and a reset is triggered for the reset
timeout period. The internal watchdog timer clears whenever reset is asserted,
the manual reset is asserted, or WDI sees a rising or falling edge.
22GND Ground
33MR
Active-Low Manual Reset Input. Drive MR low to initiate a reset. The reset output
remains asserted while MR is held low and for the reset timeout period after MR
transitions high. Leave MR unconnected or connect to V
CC
if unused. MR is
internally pulled up to V
CC
through 10kΩ.
4—RESET
Active-Low Open-Drain or Push-Pull Reset Output. RESET transitions from high to
low when V
CC
drops below the selected reset threshold, MR is pulled low, or the
watchdog timer expires. RESET remains low for the reset timeout period after
V
CC
exceeds the device reset threshold, MR deasserts, or after the watchdog
timer expires. Push-pull RESET outputs are referenced to V
CC
. Open-drain
RESET outputs require an external pullup resistor.
55V
CC
Supply Voltage. Input for V
CC
reset monitor. For noisy systems, bypass V
CC
with
a 0.1µF capacitor to GND.
—4RESET
Active-High Push-Pull Reset Output. RESET transitions from low to high when
V
CC
drops below the selected reset threshold, MR is pulled low, or the watchdog
timer expires. RESET remains high for the reset timeout period after V
CC
exceeds the device reset threshold, MR deasserts, or after the watchdog timer
expires. RESET is referenced to V
CC
.
