S-1411 Datasheet, PDF (8/36 Pages) –

LOW CURRENT CONSUMPTION WATCHDOG TIMER WITH RESET FUNCTION
S-1410/1411 Series
Rev.2.0_00
4. CWDT pin
This is a pin to connect an external capacitor in order to generate the watchdog time-out period (t_WDU) and the
watchdog double pulse detection time (t_WDL). The capacitor is charged and discharged by an internal constant
current circuit.
t_WDU is calculated by using the following equation.
t_WDU = 50,000,000 × C_WDT [F] + 0.0011
Moreover, t_WDL is calculated by using the following equation.
t_WDL =
t_WDU
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5. WEN pin
This is a pin to switch Enable / Disable of the watchdog timer.
When the WEN pin logic is active "H", the watchdog timer becomes Enable if the input is "H", and the
charge-discharge operation is performed at the CWDT pin. In the active "H" product, the constant current source
(0.3 μA typ.) is connected to the WEN pin, and it is pulled down internally.
_________
6. WDO pin
This pin combines the reset output and the w_{_}a_{__}t_{_}c_{__}h_{__}dog output.
Be sure to connect a pull-up resistor to the WDO pin in the product without an output pull-up resistor.
7. WDI pin
This is an input pin to receive a signal from the monitored object. By being input an edge at an appropriate timing, the
WDI pin confirms the normal operation of the monitored object.
The constant current source (0.3 μA typ.) is connected to the WDI pin, and it is pulled down internally.
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