TPS3813xxx Family Processor Supervisory Circuits With Window-Watchdog

1 Features

• Window-watchdog with programmable delay and

window ratio

• 6-Pin SOT-23 package

• Supply current of 9µA (typical)

• Power-on reset generator with a fixed delay time of

25ms

• Precision supply voltage monitor (VIT):

2.5V, 3V, 3.3V, and 5V

• Open-drain reset output

• Temperature range:  –40°C to 85°C

2 Applications

• Active Antenna System mMIMO (AAS)

• Storage area network

• Electricity meters

• Safety critical systems

• Infustion pump

• HVAC controller

V

DD

V

DD

WDR

WDT

WDI

GND

TPS3813

V

DD

RESET

I/O

GND

µC

C

WP

0.1 µF

0.1 µF

R

Copyright © 2016, Texas Instruments Incorporated

RESET

Typical Operating Circuit

3 Description

The TPS3813xxx family of supervisory circuits provide

circuit initialization and timing supervision, primarily

for DSPs and processor-based systems.

During power on, RESET is asserted when supply

voltage (VDD) becomes higher than 1.1V. Thereafter,

the supervisory circuit monitors VDD and keeps

RESET active as long as VDD remains below the

threshold voltage (VIT). An internal timer delays the

return of the output to the inactive state (high) to

ensure proper system reset. The delay time,

td = 25ms typical, starts after VDD has risen above

the threshold voltage (VIT). When the supply voltage

drops below the threshold voltage (VIT), the output

becomes active (low) again. No external components

are required. All the devices of this family have a

fixed-sense threshold voltage (VIT) set by an internal

voltage divider.

For safety critical applications the TPS3813xxx

family incorporates a so-called window-watchdog

with programmable delay and window ratio. The

upper limit of the watchdog time-out can be set

by either connecting WDT to GND, VDD, or using

an external capacitor. The lower limit and thus the

window ratio is set by connecting WDR to GND or

VDD. The supervised processor now needs to trigger

the TPS3813xxx within this window not to assert a

RESET.

The product spectrum is designed for supply voltages

of 2.5V, 3V, 3.3V, and 5V. The circuits are available in

a 6-pin SOT-23 package.

The TPS3813xxx devices are characterized for

operation over a temperature range of –40°C to 85°C.

Device Information

PART NUMBER

PACKAGE (1)

BODY SIZE (NOM)

(2)

TPS3813xxx

SOT-23 (6)

2.90mm × 1.60mm

(1)

For all available packages, see the orderable addendum at

the end of the data sheet.

(2)

The package size (length × width) is a nominal value and

includes pins, where applicable.

TPS3813

SLVS331J – DECEMBER 2000 – REVISED AUGUST 2024

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.