SA555 Fairchild Semiconductor, SA555 Datasheet - Page 4

• Manufacturer Part Number: SA555
• Description: Timers & Support Products
• Manufacturer: Fairchild Semiconductor
• Type: Standardr

Specifications of SA555

• Number Of Internal Timers: 1
• Supply Voltage (max): 16 V
• Supply Voltage (min): 4.5 V
• Maximum Power Dissipation: 600 mW
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: Through Hole
• Package / Case: PDIP-8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

LM555/NE555/SA555
Application Information
Application Information
Application Information
Application Information
Table 1 below is the basic operating table of 555 timer:
When the low signal input is applied to the reset terminal, the timer output remains low regardless of the threshold voltage or
the trigger voltage. Only when the high signal is applied to the reset terminal, the timer's output changes according to
threshold voltage and trigger voltage.
When the threshold voltage exceeds 2/3 of the supply voltage while the timer output is high, the timer's internal discharge Tr.
turns on, lowering the threshold voltage to below 1/3 of the supply voltage. During this time, the timer output is maintained
low. Later, if a low signal is applied to the trigger voltage so that it becomes 1/3 of the supply voltage, the timer's internal
discharge Tr. turns off, increasing the threshold voltage and driving the timer output again at high.
1. Monostable Operation
1. Monostable Operation
1. Monostable Operation
1. Monostable Operation
4 4 4 4
Vcc / 3 < V
Trigger
Threshold Voltage
Threshold Voltage
Threshold Voltage
Threshold Voltage
Figure 3. Waveforms of Monostable Operation
Figure 3. Waveforms of Monostable Operation
Figure 3. Waveforms of Monostable Operation
Figure 3. Waveforms of Monostable Operation
R
V
V
(V (V (V (V
L
th
Don't care
th
th th th th
> 2Vcc / 3
Figure 1. Monoatable Circuit
Figure 1. Monoatable Circuit
Figure 1. Monoatable Circuit
Figure 1. Monoatable Circuit
< Vcc / 3
)(PIN 6)
)(PIN 6)
)(PIN 6)
)(PIN 6)
th
3
2
< 2 Vcc / 3
OUT
TRIG
RESET
4
GND
1
Vcc / 3 < V
THRES
Vcc
DISCH
CONT
8
Trigger Voltage
Trigger Voltage
Trigger Voltage
Trigger Voltage
V
V
(V (V (V (V
th
Don't care
th
tr tr tr tr
> 2Vcc / 3
< Vcc / 3
)(PIN 2)
)(PIN 2)
6
)(PIN 2)
)(PIN 2)
7
5
th
Table 1. Basic Operating Table
Table 1. Basic Operating Table
Table 1. Basic Operating Table
Table 1. Basic Operating Table
< 2 Vcc / 3
C2
+Vcc
R
C1
A
Reset(PIN 4)
Reset(PIN 4)
Reset(PIN 4)
Reset(PIN 4)
High
High
High
Low
Figure 2. Resistance and Capacitance vs.
Figure 2. Resistance and Capacitance vs.
Figure 2. Resistance and Capacitance vs.
Figure 2. Resistance and Capacitance vs.
10 10 10 10
10 10 10 10
10 10 10 10
10 10 10 10
10 10 10 10
10 10 10 10
-1 -1 -1 -1
-2 -2 -2 -2
-3 -3 -3 -3
2 2 2 2
1 1 1 1
0 0 0 0
10 10 10 10
-5 -5 -5 -5
10 10 10 10
-4 -4 -4 -4
Time delay(t
Time delay(t
Time delay(t
Time delay(t
Output(PIN 3)
Output(PIN 3)
Output(PIN 3)
Output(PIN 3)
10 10 10 10
-3 -3 -3 -3
High
Low
Low
Time Delay(s)
Time Delay(s)
-
Time Delay(s)
Time Delay(s)
10 10 10 10
-2 -2 -2 -2
d d d d
) ) ) )
10 10 10 10
-1 -1 -1 -1
10 10 10 10
0 0 0 0
Discharging Tr.
Discharging Tr.
Discharging Tr.
Discharging Tr.
10 10 10 10
(PIN 7)
(PIN 7)
(PIN 7)
(PIN 7)
1 1 1 1
OFF
ON
ON
-
10 10 10 10
2 2 2 2