Open-drain, supply voltage supervisor with manual reset

The TPS312x family

of voltage supervisory circuits provides voltage monitoring down to 1.2V rails and

timing supervision, primarily for DSP and processor-based 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.

Built-in 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.