8 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification,

and TI does not warrant its accuracy or completeness. TI’s customers are responsible for

determining suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

8.1 Application Information

The TPS3813xxx is a voltage supervisor that incorporates a window-watchdog timer, allowing for comprehensive

supervision of microcontrollers and other similar devices. The TPS3813xxx can be operated from a VDD rail of

2V to 6V with a user-programmable watchdog time-out from 0.25s to 2.5s. The following sections describe how

to properly use this device, depending on the requirements of the final application.

8.2 Typical Application

A typical application example (see Figure 8-1) is used to describe the function of the watchdog in more detail. To

configure the window watchdog function, two pins are provided by the TPS3813xxx. These pins set the window

time-out and ratio. The window watchdog ratio is a fixed ratio, which determines the lower boundary of the

window frame. It can be configured in two different frame sizes.

WDI

WDR

WDT

GND

TPS3813

I/O

GND

Position 1

Position 2

Position 3

Position 5

Position 4

R1

R2

(A)

μC

C

(ext)

V

DD

V

DD

V

DD

V

DD

V

DD

RESET

RESET

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0.1 F

0.1 F

A.

Use this pulldown resistor if a GPIO pin is used to drive the WDI input pin of the TPS3813xxx to keep the WDI pin from floating during

power up.

Figure 8-1. Application Example

8.2.1 Design Requirements

The TPS3813xxx RESET output can be used to drive the RESET pin of a microcontroller to initiate a reset

event. The RESET pin of the TPS3813xxx can be pulled high with a 1MΩ resistor; the watchdog window

timing is controlled by the WDT and WDR pins, and is set depending on the reset requirement times of the

microprocessor.

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TPS3813

SLVS331J – DECEMBER 2000 – REVISED AUGUST 2024

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