MAX6369 Maxim, MAX6369 Datasheet - Page 6

• Manufacturer Part Number: MAX6369
• Description: Pin-Selectable Watchdog Timers
• Manufacturer: Maxim

Pin-Selectable Watchdog Timers
Figure 1. Functional Diagram
Figure 2. Watchdog Timing
• Watchdog Timeout Period:
6
Normal operating watchdog timeout period after the
initial startup delay.
A watchdog output pulse is asserted if a valid watch-
dog input transition is not received before the timeout
period elapses.
Eight pin-selectable timeout period options for each
device, from 30µs to 60s.
Pin-selectable watchdog timer disable feature.
_______________________________________________________________________________________
SET 2
SET 1
SET 0
A
B
C
D
E
F
G
V
WDO
WDI
CC
TRANSITIONS ON WDI IGNORED DURING SETUP DELAY.
TRANSITION(S) ON WDI IGNORED DURING STARTUP DELAY PERIOD.
WATCHDOG TIMER STARTS AFTER STARTUP DELAY AND WDO IS DEASSERTED.
TRANSITION OCCURS BEFORE WATCHDOG TIMEOUT PERIOD. WATCHDOG
TIMER CLEARS AND STARTS TIMER AGAIN.
WATCHDOG TIMES OUT, WDO ASSERTS.
TRANSITIONS ON WDI IGNORED WHEN WDO ASSERTED.
WATCHDOG TIMER STARTS AFTER WDO DEASSERTS.
MAX6369–MAX6374
t
A
SETUP
CONTROL
A
LOGIC
B
t
DELAY
V
CC
ENABLE
SET WATCHDOG TIMEOUT
SET STARTUP DELAY
C
TIMER CIRCUITRY
TRANSITION
WATCHDOG
DETECTOR
CLEAR
t
GND
WDI
WD
D
• Watchdog Output/Timing Options:
Each device has a watchdog startup delay that is initi-
ated when the supervisor is first powered or after the
user modifies any of the logic control set inputs. The
watchdog timer does not begin to count down until the
Open drain, active low with 100ms minimum watch-
dog output pulse (MAX6369/MAX6371/MAX6373).
Push-pull, active low with 1ms minimum watchdog
output pulse (MAX6370/MAX6372/MAX6374).
t
WD
OUT
EN
E F
t
WDO
OUTPUT
G
t
WD
WDO
E