R1

R

S

1

THRES

R

R

R

TRIG

2

1

GND

DISCH

7

3

OUT

6

VDD

8

5

CONT

RESET

4

14

TLC555

SLFS043I – SEPTEMBER 1983 – REVISED JULY 2019

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Copyright © 1983–2019, Texas Instruments Incorporated

7 Detailed Description

7.1 Overview

The TLC555 is a precision timing device used for general-purpose timing applications up to 2.1 MHz. All inputs

are level sensitive not edge triggered inputs.

7.2 Functional Block Diagram

Pin numbers are for all packages except the PW and FK package. RESET can override TRIG, which can override

and temperature for a temperature stable control voltage ratio.

7.3 Feature Description

7.3.1 Monostable Operation

For monostable operation, any of these timers can be connected as shown in Figure 9. If the output is low,

application of a negative-going pulse to the trigger (TRIG) sets the internal latch; the output goes high, and

capacitor reaches the threshold voltage of the threshold (THRES) input. If TRIG has returned to a high level, the

output of the threshold comparator resets the internal latch, the output goes low, the discharge pin goes low

which quickly discharges capacitor C.