8 Detailed Description

8.1 Overview

The TLV803 family of supervisory circuits provides circuit initialization and timing supervision. The TLV853 and

TLV863 are both functionally equivalent to the TLV803. These devices output a logic low whenever VDD drops

below the negative-going threshold voltage (VIT–). The output, RESET, remains low for approximately 200 ms

after the VDD voltage exceeds the positive-going threshold voltage (VIT– + Vhys). These devices are designed to

ignore fast transients on the VDD pin.

8.2 Functional Block Diagram

R2

_

+

R1

VDD

GND

RESET

TLV8x3

Oscillator

Reference

Voltage

of 1.137 V

Reset

Logic

+

Timer

8.3 Feature Description

8.3.1 VDD Transient Rejection

The TLV803 has built-in rejection of fast transients on the VDD pin. The rejection of transients depends on both

the duration and the amplitude of the transient. The amplitude of the transient is measured from the bottom of

the transient to the negative threshold voltage of the TLV803, as shown in Figure 8-1.

V

DD

Transient

Amplitude

Duration

V

IT-

tw

Figure 8-1. Voltage Transient Measurement

The TLV803 does not respond to transients that are fast duration/low amplitude or long duration/small amplitude.

Transients meeting or longer than the tw specified in the switching characteristics section triggers a reset.

TLV803, TLV853, TLV863

SBVS157E – APRIL 2011 – REVISED DECEMBER 2020

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8

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