V

DD

VCC

PB1

RST

GND

Reset

Microprocessor

Device

PB2

V

= 1.6 V to 6.5 V

IN

TS

+

GPIO

GPIO

Push-Button

Switch 2

Push-Button

Switch 1

TPS3420

TPS3421

TPS3422

www.ti.com

SBVS211A – AUGUST 2012 – REVISED MARCH 2013

DETAILED DESCRIPTION

OVERVIEW

The TPS342x are a family of push-button reset devices with an extended setup period that prevents resets from

occurring as a result of short-duration switch closures. See the Device Family Options table for details.

The TPS3420 is a dual-channel device with an output that asserts when both inputs (PB1 and PB2) are held low

for the push-button timer duration, and deasserts when either input PBx is released.

The TPS3421 is a dual-channel device with an output that asserts when both inputs (PB1 and PB2) are held low

for the push-button timer duration, and deasserts after the reset timeout duration.

TPS3422 is a single-channel device with an output that asserts when the PB1 input is held low for the push-

button timer duration, and deasserts after the reset timeout duration.

The TPS342x family also has a TS pin that selects between two different push-button timing options by

DEVICE INPUTS

This section describes the input of the TPS342x devices.

TPS3420 Inputs (PB1, PB2)

input conditions are met (that is, when both inputs are simultaneously held low for the push-button timer period,

high. The reset pulse occurs only one time after each valid input condition. At least one input pin must be

shown in Figure 14.

NOTE: Connect TS to VCC or ground for different PB time delays. Connect one PB input to ground for use as a single channel.

Figure 14. TPS3420 Application Diagram

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Product Folder Links: TPS3420 TPS3421 TPS3422