1 Features

• Minimum supply voltage of 0.9V

• Supply voltage supervision range:

– 1.2V, 1.5V, 1.8V (TPS312x)

– 3V (TPS3125 devices only)

– Other versions on request

• Power-on reset generator with fixed delay time of

180ms

• Manual reset input (TPS3123/5/6/8)

• Watchdog timer retriggers the RESET output at

VDD ≥ VIT-

• Supply current of 14μA (typical)

• Small SOT23-5 package

• Temperature range of –40°C to +85°C

• Reset output available in Push-Pull (Active-Low

and High) and Open-Drain (Active-Low)

2 Applications

• Portable / battery-powered equipment

• Wireless communication systems

• Industrial automation

• Servers

• Building automation

3 Description

The TPS312x family of voltage supervisory circuits

provides voltage monitoring down to 1.2V rails and

timing supervision, primarily for DSP and processorbased

systems. All devices in the family monitor

the power rail and assert RESET output when the

power rail is under the threshold voltage target

(VIT-). The threshold voltage is programmed into

the device to minimize external components. Builtin

Builtin

hysteresis prevents false triggering. The RESET

output is not valid for supply voltage (VDD) under 0.9V.

The TPS312x family includes devices with active

high output for use as disable during malfunction

and active-low outputs for most systems where high

output indicates properly functioning system.

The TPS3123/3124/3128 also include the watchdog

timer functionality to monitor timely digital pulses from

the processor and issue an alert if the expected

pulse does not arrive on time due to potential

software freeze or hang. Such integration of supply

rail monitoring and the watch dog timer feature is

very helpful in always on systems, such as Factory

Automation and Communications Infrastructure.

In addition the TPS3123/5/6/8 devices incorporate a

manual reset input, MR, to force RESET triggered

by an event unrelated to the voltage rail monitoring

of the pulses monitored by the watch dog timer. A

low level at MR causes RESET to become active.

The TPS3124 devices do not have the input MR,

but include a high-level output RESET same as the

TPS3125 and TPS3126 devices.

All devices in the family are available in a 5-pin

SOT23-5 package and are characterized for operation

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