FOR AUTOMOTIVE 125°C OPERATION LOW CURRENT CONSUMPTION WATCHDOG TIMER WITH RESET FUNCTION

S-19400/19401 Series

7



Pin Functions

Refer to " Operation" for details.

1. W

____

/ T pin (S-19400 Series only)

This is a pin to switch the watchdog mode.

The S-19400 Series changes to the time-out mode when the W

___

/ T pin is "H", and changes to the window mode

when the W

___

/ T pin is "L". Switching the mode is prohibited during the operation.

The constant current source (0.3

μA typ.) is connected to the W

___

/ T pin, and it is pulled down internally.

1. 1 Time-out mode (W

___

/ T pin = "H")

The S-19400 Series detects an abnormality when not inputting an edge to the WDI pin during the watchdog

________

pin.

W / T

(S-19400 only)

WDI

(Rising edge)

WDO

"H"

Figure 5 Abnormality Detection in Time-out Mode

1. 2 Window mode (W

___

/ T pin = "L")

specific period of time (the discharge time due to an edge detection

inputting an edge to the WDI pin, the WDO

________

pin output changes from "H" to "L".

W / T

(S-19400 only)

WDI

(Rising edge)

WDO

"L"

Figure 6 Abnormality Detection in Window Mode

2. RST

________

pin (S-19401 Series only)

This is a reset output pin. It outputs "L" when detecting a low voltage.

Be sure to connect a pull-up resistor to the RST

_______

pin in the product without an output pull-up resistor.

3. CPOR pin

The capacitor is charged and discharged by an internal constant current circuit, and the charge-discharge duration is