SE555 datasheet(10/20 Pages) STMICROELECTRONICS

Part #	SE555

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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10 / 20 page

Application information

NE555 - SA555 - SE555

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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 (pin 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

SE555 Datasheet(PDF) 10 Page - STMicroelectronics