Fairchild Semiconductor NE555, LM555, SA555 Datasheet

LM555/NE555/SA555

Single Timer

Features

FeaturesFeatures

• High Current Drive Capability (200mA)

• Adjustable Duty Cycle

• Tem perature Stability of 0.005%/°C

• Timing From µSec to Hours

• Turn off Time Less Than 2µSec

Applications

ApplicationsApplications

• Precision Timing

• Pulse Generation

• Time Delay Generation

• Sequential Timing

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Description

DescriptionDescription

The LM555/NE555/SA555 is a highly stable controller capable of producing accurate timing pulses. With a monostable operation, the time delay is controlled by one external resistor and one capacitor. With an astable operation, the frequency and duty cycle are accurately controlled by two external resistors and one capacitor.

8-DIP

8-DIP8-DIP

1

8-SOP

8-SOP8-SOP

Internal Block Diagram

Internal Block DiagramInternal Block Diagram

GND

GNDGND

Trigger

TriggerTrigger

Output

OutputOutput

Reset

ResetReset

1

RRRRR

1111

Comp.

Comp.Comp.

2222

OutPut

OutPutOutPut

3333

Stage

StageStage

4444

Vref

VrefVref

RR

Discharging Tr.

Discharging Tr.Discharging Tr.

F/F

F/FF/F

Comp.

Comp.Comp.

R

RR

8888

Vcc

VccVcc

7777

Discharge

DischargeDischarge

6666

Threshold

ThresholdThreshold

Control

ControlControl

5555

Voltage

VoltageVoltage

Rev. 1.0.3

LM555/NE555/SA555

Absolute Maximum Ratings (T

Absolute Maximum Ratings (TAbsolute Maximum Ratings (T

Parameter

Parameter Symbol

ParameterParameter Supply Voltage V Lead Temperature (Soldering 10sec) T Power Dissipation P Operating Temperature Range

LM555/NE555 SA555

Storage Temperature Range T

= 25

= 25°°°°C)

= 25 = 25

AAAA

C)

C)C)

Symbol Value

SymbolSymbol

LEAD

T

OPR

STG

CC

D

Value Unit

ValueValue

16 V 300 °C 600 mW

0 ~ +70

-40 ~ +85

-65 ~ +150 °C

Unit

UnitUnit

°C

2222

Electrical Characteristics

Electrical CharacteristicsElectrical Characteristics

(TA = 25°C, V

Parameter

Parameter Symbol

ParameterParameter

= 5 ~ 15V, unless otherwise specified)

CC

Symbol Conditions

SymbolSymbol

Supply Voltage V Supply Current (Low Stable) (Note1) I

CC

Timing Error (Monostable) Initial Accuracy (Note2) Drift with Temperature (Note4) Drift with Supply Voltage (Note4)

ACCUR

∆t/∆T

∆t/∆V

CC

LM555/NE555/SA555

Conditions Min.

ConditionsConditions

Min. Typ.

Min.Min.

Typ. Max.

Typ.Typ.

Max. Unit

Max.Max.

-4.5-16V

VCC = 5V, RL = ∞ -36mA

= 15V, RL = ∞ -7.515mA

V

CC

RA = 1kΩ to100kΩ C = 0.1µF

CC

-1.0 50

0.1

3.0

0.5

Unit

UnitUnit

%

ppm/°C

%/V

Timing Error (Astable) Intial Accuracy (Note2) Drift with Temperature (Note4) Drift with Supply Voltage (Note4)

ACCUR

∆t/∆T

∆t/∆V

Control Voltage V

Threshold Voltage V Threshold Current (Note3) I Trigger Voltage V Trigger Current I

Reset Voltage V Reset Current I

Low Output Voltage V

High Output Voltage V

Rise Time of Output (Note4) t Fall Time of Output (Note4) t Discharge Leakage Current I

C

TH

TR

RST

OL

OH

R F

LKG

RA = 1kΩ to 100kΩ C = 0.1µF

CC

-

2.25 150

0.3 VCC = 15V 9.0 10.0 11.0 V V

= 5V 2.6 3.33 4.0 V

CC

VCC = 15V - 10.0 - V

= 5V - 3.33 - V

V

CC

-----0.10.25 µA

V

= 5V 1.1 1.67 2.2 V

CC

= 15V 4.5 5 5.6 V

V

CC

V

= 0V 0.01 2.0 µA

TR

----0.40.71.0V

----0.10.4mA

VCC = 15V I

SINK

I

SINK

V

CC

I

SINK

= 10mA = 50mA

= 5V

= 5mA

-0.06

0.3

-0.050.35 V

VCC = 15V I

SOURCE

I

SOURCE

V

CC

I

SOURCE

= 200mA = 100mA 12.75

= 5V

= 100mA

12.5

13.3

2.75 3.3 - V

---- - 100 - ns

---- - 20 100 nA

-% ppm/°C

%/V

0.25

0.75

V V

-V

V

Notes:

Notes:Notes:

1. When the output is high, the supply current is typically 1mA less than at V

2. Tested at V

3. This will determine the maximum value of R total R = 6.7MΩ.

4. These parameters, although guaranteed, are not 100% tested in production.

= 5.0V and V

CC

= 15V.

+ RB for 15V operation, the max. total R = 20MΩ, and for 5V operation, the max.

A

CC

= 5V.

3333

LM555/NE555/SA555

Application Information

Application InformationApplication Information

Table 1 below is the basic operating table of 555 timer:

Table 1. Basic Operating Table

Table 1. Basic Operating TableTable 1. Basic Operating Table

Threshold Voltage

Threshold Voltage Threshold Voltage

(V

)(PIN 6)

(V(V

)(PIN 6))(PIN 6)

th

thth

Trigger Voltage

Trigger VoltageTrigger Voltage

(V

)(PIN 2)

(V(V

)(PIN 2))(PIN 2)

tr

trtr

Reset(PIN 4)

Reset(PIN 4) Output(PIN 3)

Reset(PIN 4)Reset(PIN 4)

Output(PIN 3)

Output(PIN 3)Output(PIN 3)

Discharging Tr.

Discharging Tr.Discharging Tr.

(PIN 7)

(PIN 7)(PIN 7)

Don't care Don't care Low Low ON

> 2Vcc / 3 Vth > 2Vcc / 3 High Low ON

V

th

Vcc / 3 < V

< 2 Vcc / 3 Vcc / 3 < Vth < 2 Vcc / 3 High - -

th

< Vcc / 3 Vth < Vcc / 3 High High OFF

V

th

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 Operation1. Monostable Operation

Trigger

4

RESET

TRIG

2

OUT

3

GND

L

Figure 1. Monoatable Circuit

Figure 1. Monoatable CircuitFigure 1. Monoatable Circuit

1

8

Vcc DISCH

THRES

CONT

+Vcc

2222

10

R

A

7

6

5

C1

C2R

1010

1111

10

1010

R

0000

10

1010

-1

-1-1

10

1010

Capacitance(uF)

Capacitance(uF)Capacitance(uF)

Capacitance(uF)

-2

-2-2

10

1010

-3

-3-3

10

1010

-5

-5-5

10

1010

Figure 2. Resistance and Capacitance vs.

Figure 2. Resistance and Capacitance vs.Figure 2. Resistance and Capacitance vs.

RR

-4

-3

-4-4

-3-3

10

1010

Time delay( t

Time delay( tTime delay(t

Ω

ΩΩ

=1k

=1k=1k

A

AA

-2

-2-2

10

1010

Time Delay(s)

Time Delay(s)Time Delay (s)

Ω

ΩΩ

Ω

ΩΩ

10k

10k10k

10

1010

))))

dddd

1M

100k

1M

100k

1M1M

100k100 k

-1

0000

-1-1

10

1010

Ω

ΩΩ

Ω

ΩΩ

10M

10M10M

1111

2222

10

1010

Figure 3. Waveforms of Monostable Operation

Figure 3. Waveforms of Monostable OperationFigure 3. Waveforms of Monostable Operation

4444

LM555/NE555/SA555

Figure 1 illustrates a monostable circuit. In this mode, the timer generates a fixed pulse whenever the trigger voltage falls below Vcc/3. When the trigger pulse voltage applied to the #2 pin falls below Vcc/3 while the timer output is low, the timer's internal flip-flop turns the discharging Tr. off and causes the timer output to become high by charging the external capacitor C1 and setting the flip-flop output at the same time. The voltage across the external capacitor C1, V at td=1.1R for the V

*C. Hence, capacitor C1 is charged through resistor RA. The greater the time constant RAC, the longer it takes

A

to reach 2Vcc/3. In other words, the time constant RAC controls the output pulse width.

C1

increases exponentially with the time constant t=RA*C and reaches 2Vcc/3

C1

When the applied voltage to the capacitor C1 reaches 2Vcc/3, the comparator on the trigger terminal resets the flip-flop, turning the discharging Tr. on. At this time, C1 begins to discharge and the timer output converts to low. In this way, the timer operating in the monostable repeats the above process. Figure 2 shows the time constant relationship based on R

and C. Figure 3 shows the general waveforms during the monostable operation.

A

It must be noted that , for a norma l oper ati on, the trig ger pul se vo ltage needs to ma intai n a min imum of Vcc/ 3 befor e the time r output turns low. That is, alth ough the output remains unaf fected even if a dif f erent trigger pulse is applied while the output is high, it may be affected and the waveform does not operate properly if the trigger pulse voltage at the end of the output pulse remains at below Vcc/3. Figure 4 shows such a timer output abnormality.

Figure 4. Waveforms of Monostable Operation (abnormal)

Figure 4. Waveforms of Monostable Operation (abnormal)Figure 4. Waveforms of Monostable Operation (abnormal)

2. Astable Operation

2. Astable Operation2. Astable Operation

+Vcc

R

4

RESET

TRIG

2

OUT

3

GND

L

Figure 5. Astable Circuit

Figure 5. Astable CircuitFigure 5. Astable Circuit

8

Vcc DISCH

THRES

1

CONT

7

R

6

5

C2R

A

B

C1

100k

100k100k

Ω

ΩΩ

1M

1M1M

Ω

ΩΩ

10 100

1010

Frequency(Hz)

Frequency(Hz)Frequency(Hz)

1k

1k1k

Ω

ΩΩ

10k

10k10k

Ω

ΩΩ

100 1k

100100

(R

+2R

))))

(R(R

+2R+2R

AAAA

BBBB

1k 10k

1k1k

10k 100k

100k

10k10k

100k100k

100

100100

10

1010

1111

0.1

0.10.1

Capacitance(uF)

Capacitance(uF)Capacitance(uF)

Capacitance(uF)

0.01

0.010.01

1E-3

1E-31E-3

100m

100m 111110

100m100m

Figure 6. Capacitance and Resistance vs. Frequency

Figure 6. Capacitance and Resistance vs. FrequencyFigure 6. Capacitance and Resistance vs. Frequency

10M

10M10M

10M

Ω

ΩΩ

5555