3-pin voltage supervisor (reset IC) with active-low, push-pull reset

The TPS3809 family of supervisory

circuits provides circuit initialization and timing supervision, primarily for DSPs

and processor-based systems. The newer TLV809E device is an alternative with the same pins, functions and

electrical parameters.

During power-on,

RESET is asserted when the supply voltage VDD

becomes higher than 1.1 V. 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(typ) = 200 ms, 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.

The product spectrum is designed for

supply voltages of 2.5 V, 3 V, 3.3 V, and 5 V. The circuits are available in a 3-pin

SOT-23. The TPS3809 devices are characterized for operation over a temperature range

of –40°C to 85°C.