Datasheet

LTC694-3.3/LTC695-3.3
8
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PIN FUNCTIONS
WDI: Watchdog Input. WDI is a three-level input. Driving
WDI either high or low for longer than the watchdog timeout
period, forces both RESET and WDO low. Floating WDI
disables the watchdog timer. The timer resets itself with
each transition of the watchdog input (see Figure 11).
CHARGE
PUMP
M2
M1
V
BATT
V
CC
CE IN
PFI
OSC IN
OSC SEL
WDI
RESET PULSE
GENERATOR
WATCHDOG
TIMER
RESET
BATT ON
V
OUT
C1
1.3V
GND
–
+
–
+
C2
OSC
TRANSITION
DETECTOR
–
+
C3
WDO
RESET
PFO
LOW LINE
CE OUT
694/5-3.3 BD
BLOCK DIAGRAM
WDO: Watchdog Logic Output. When the watchdog input
remains either high or low for longer than the watchdog
timeout period, WDO goes low. WDO is set high whenever
there is a transition on the WDI pin, or LOW
_
LINE goes
low. The watchdog timer can be disabled by floating WDI
(see Figure 11).