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

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.