SLFS022 – D1669, SEPTEMBER 1973—REVISED FEBRUARY 1992

NE555, SA555, SE555, SE555C

PRECISION TIMERS

POST OFFICE BOX 655303

10

APPLICATION INFORMATION

astable operation

to the threshold input causes the timer to self-trigger and run as a multivibrator. The capacitor C will charge

This astable connection results in capacitor C charging and discharging between the threshold-voltage level

(

times (and therefore the frequency and duty cycle) are independent of the supply voltage.

GND

OUT

VCC

CONT

RESET

DISCH

THRES

TRIG

C

RB

RA

Output

RL

0.01

VCC

(5 V to 15 V)

(see Note A)

Time – 0.5 ms/div

t

H

Capacitor Voltage

Output Voltage

tL

RL = 1 kΩ

See Figure 12

C = 0.15

µF

NOTE A: Decoupling CONT voltage to ground with a

capacitor may improve operation. This should be

evaluated for individual applications.

Open

58

4

7

6

2

3

1

Pin numbrs shown are for the D, JG, and P packages.

Figure 12. Circuit for Astable Operation

Figure 13. Typical Astable Waveforms