Rainbow Electronics MAX6869 - Manual (Page 9)

MAX6854–MAX6869
Nanopower µP Supervisory Circuits with
Optional Manual Reset, Watchdog Timer
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MAX6867/MAX6868/MAX6869 Pin Description
PIN
MAX6867/
MAX6869
MAX6868
NAME FUNCTION
1 1 WDI
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.
2 2 GND Ground
3 3 MR
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 10k
Ω
.
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.
5 5 V CC
Supply Voltage. Input for V CC reset monitor. For noisy systems, bypass V CC with
a 0.1µF capacitor to GND.
— 4 RESET
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 .