1

FEATURES

1

2

3

4

8

7

6

5

GND

TRIG

OUT

RESET

V

CC

DISCH

THRES

CONT

3

2

1 20 19

9 10 11 12 13

4

5

6

7

8

18

17

16

15

14

NC

DISCH

NC

THRES

NC

NC

TRIG

NC

OUT

NC

NC – No internal connection

NA555...D OR P PACKAGE

NE555...D, P, PS, OR PW PACKAGE

SA555...D OR P PACKAGE

SE555...D, JG, OR P PACKAGE

(TOP VIEW)

SE555...FK PACKAGE

(TOP VIEW)

DESCRIPTION/ORDERING INFORMATION

NA555, NE555, SA555, SE555

PRECISION TIMERS

SLFS022G – SEPTEMBER 1973 – REVISED MARCH 2008

www.ti.com

• Timing From Microseconds to Hours

• Adjustable Duty Cycle

• Astable or Monostable Operation

• TTL-Compatible Output Can Sink or Source up

to 200 mA

These devices are precision timing circuits capable of producing accurate time delays or oscillation. In the

time-delay or monostable mode of operation, the timed interval is controlled by a single external resistor and

capacitor network. In the astable mode of operation, the frequency and duty cycle can be controlled

independently with two external resistors and a single external capacitor.

altered by use of the control-voltage terminal. When the trigger input falls below the trigger level, the flip-flop is

set, and the output goes high. If the trigger input is above the trigger level and the threshold input is above the

threshold level, the flip-flop is reset and the output is low. The reset (RESET) input can override all other inputs

and can be used to initiate a new timing cycle. When RESET goes low, the flip-flop is reset, and the output goes

low. When the output is low, a low-impedance path is provided between discharge (DISCH) and ground.

The output circuit is capable of sinking or sourcing current up to 200 mA. Operation is specified for supplies of

5 V to 15 V. With a 5-V supply, output levels are compatible with TTL inputs.

1

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

PRODUCTION DATA information is current as of publication date.

Copyright © 1973–2008, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

On products compliant to MIL-PRF-38535, all parameters are

Instruments standard warranty. Production processing does not

tested unless otherwise noted. On all other products, production

necessarily include testing of all parameters.

processing does not necessarily include testing of all parameters.