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
NE555 - SA555 - SE555 Application information
Doc ID 2182 Rev 6 13/20
Figure 20 shows the waveforms generator by the linear ramp.
The time interval is given by:
Figure 20. Linear ramp
4.5 50% duty cycle oscillator
For a 50% duty cycle, the resistors R
A
and R
B
can be connected as in Figure 21. The time
period for the output high is the same as for astable operation (see Section 4.2 on page 9):
t1 = 0.693 R
A
C
For the output low it is
Thus the frequency of oscillation is:
T =
(2/3 Vcc RE (R1+R2) C
R1 Vcc - VBE (R1+R2)
--------------------------------------------------------------- -
VBE = 0.6V
V
CC
= 5 V
Time:
20 µs/DIV
R
1
+ 47 kΩ
R
2
= 100 kΩ
R
E
= 2.7 kΩ
C = 0.01 µF
Top trace: input 3 V/DIV
Middle trace: output 5 V/DIV
Bottom trace: output 5 V/DIV
Bottom trace: capacitor voltage 1 V/DIV
t
2
[(R. RB)/(RA+RB)].C.Ln
RB 2RA–
2RB RA–
-------------------------- -
=
f
1
t1 t2+
---------------- -=