SA555DT datasheet(9/20 Pages) STMICROELECTRONICS

Part #	SA555DT

Description	General-purpose single bipolar timers

PDF	20 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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9 / 20 page

NE555 - SA555 - SE555

Application information

Doc ID 2182 Rev 6

9/20

Figure 13.

Waveforms in monostable operation

Figure 14.

Pulse duration versus R1C1

4.2

Astable operation

When the circuit is connected as shown in Figure 15 (pins 2 and 6 connected) it triggers

itself and free runs as a multi-vibrator. The external capacitor charges through R1 and R2

and discharges through R2 only. Thus the duty cycle can be set accurately by adjusting the

ratio of these two resistors.

In the astable mode of operation, C1 charges and discharges between 1/3 VCC and 2/3 VCC.

As in the triggered mode, the charge and discharge times and, therefore, frequency are

independent of the supply voltage.

CAPACITOR VOLTAGE = 2.0V/div

t = 0.1 ms / div

INPUT = 2.0V/div

OUTPUT VOLTAGE = 5.0V/div

R1 = 9.1k

Ω, C1 = 0.01μF, R = 1kΩ

(

μF)

1.0

0.1

0.01

0.001

100

1.0

100

(t )

μs

mss

SA555DT Datasheet(PDF) 9 Page - STMicroelectronics