Data Sheet
Table Of Contents
- 1 Schematic diagrams
- 2 Absolute maximum ratings and operating conditions
- 3 Electrical characteristics
- Table 3. Tamb = +25˚ C, VCC = +5 V to +15 V (unless otherwise specified)
- Figure 3. Minimum pulse width required for triggering
- Figure 4. Supply current versus supply voltage
- Figure 5. Delay time versus temperature
- Figure 6. Low output voltage versus output sink current
- Figure 7. Low output voltage versus output sink current
- Figure 8. Low output voltage versus output sink current
- Figure 9. High output voltage drop versus output
- Figure 10. Delay time versus supply voltage
- Figure 11. Propagation delay versus voltage level of trigger value
- 4 Application information
- 5 Package information
- 6 Ordering information
- 7 Revision history
Application information NE555 - SA555 - SE555
10/20 Doc ID 2182 Rev 6
Figure 15. Typical schematics in astable operation
Figure 16 shows the actual waveforms generated in this mode of operation.
The charge time (output HIGH) is given by:
t1 = 0.693 (R
1
+ R
2
) C
1
and the discharge time (output LOW) by:
t2 = 0.693 (R
2
) C
1
Thus the total period T is given by:
T = t1 + t2 = 0.693 (R1 + 2R2) C1
The frequency of oscillation is then:
It can easily be found from Figure 17.
The duty cycle is given by:
Output
3
4
8
7
5
1
R1
C1
2
6
R2
Control
Voltage
NE555
V
CC
= 5 to 15V
0.01
μ
F
f =
1
T
---
1.44
R1 2R2+()C1
---------------------------------------=
t1
t1 t2+()
---------------------
R1 R2+()
R1 2 R2•+()
------------------------------------ 1
R2
R1 R2+()
---------------------------
–==