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RESET

WDI

WDR

WDT

GND

TPS3813

RESET

I/O

GND

Position 1

See Note A

Position 2

See Note B

Position 3

See Note C

Position 5

See Note E

Position 4

See Note D

0.1

µF

0.1

µF

R

uC

TPS3813J25, TPS3813L30

TPS3813K33, TPS3813I50

SLVS331B – DECEMBER 2000 – REVISED JUNE 2005

value based on a ratio calculation of the overall window timeout size: For the watchdog timeout pin (WDT)

capacitor connected to WDT, it is a ratio of 1:64.5.

If the window watchdog ratio pin (WDR) is set to GND, Position 2, the lower window frame will be a value based

on a ratio calculation of the overall window timeout size: For the watchdog timeout pin (WDT) connected to GND,

WDT it will be 1:25.8.

The watchdog timeout can be set in two fixed timings of 0.25 seconds and 2.5 seconds for the window or can by

programmed by connecting a external capacitor with a low leakage current at WDT.

boundary is 19.6 ms.

A.

Watchdog window ratio

B.

Watchdog timeout set to typical 2.5 sec

C.

Watchdog timeout programmed by external capacitor

D.

Watchdog timeout set to typical 0.25 sec

Figure 2. Application Example

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