Datasheet NE555N, NE555, NE555D, SA555N, SA555 Datasheet (SGS Thomson Microelectronics)

NE555



GENERALPURPOSE SINGLE BIPOLAR TIMERS

.LOW TURN OFF TIME

.MAXIMUM OPERATING FREQUENCY

GREATERTHAN500kHz

.TIMINGFROMMICROSECONDSTO HOURS

.OPERATES IN BOTH ASTABLE AND

MONOSTABLEMODES

.HIGHOUTPUT CURRENT CAN SOURCE OR

SINK200mA

.ADJUSTABLE DUTYCYCLE

.TTL COMPATIBLE

.TEMPERATURE STABILITY OF 0.005%

DESC RIP TI ON

TheNE555monolithictimingcircuitisahighlystable
controllercapableofproducingaccuratetimedelays
or oscillation.In the time delay modeof operation,
the time is precisely controlledby one externalre­sistorandcapacitor.Forastableoperationasanos­cillator,thefree runningfrequency andthe duty cy­cle are both accuratelycontrolledwithtwoexternal
resistorsandone capacitor.The circuit maybe trig­gered and reseton fallingwaveforms, andthe out­put structurecan source or sinkup to 200mA. The
NE555 is available in plastic and ceramic minidip
packageandina8-leadmicropackageandinmetal
can packageversion.

PER

o

C

N

DIP8

(PlasticPackage)

ORDER CODES

Part

Number

NE555 0
SA555 –40
SE555 –55

Temperature

SA555 - SE555

D

SO8

(PlasticMicropackage)

Package

Range

o

C, 70oC ••

o

C, 105oC ••

o

C, 125oC ••

ND

PIN CONNE CTIONS (top view)

1

2

3

45

July 1998

8

7

6

1 - GND
2 - Trigger
3 - Output
4 - Reset
5 - Control voltage
6 - Threshold
7 - Discharge
8-V

CC

1/10

NE 555/SA555/SE555

BLOCK DI AGRAM

THRESHOLD

CONTROL VOLTAGE

TRIGGER

+

V

CC

5kΩ

COMP

5kΩ

COMP

5kΩ

R
FLIP-FLOP

S

INHIBIT/

RESET

Q

DISCHARGE

OUT

SCHE MATIC DIAGRAM

THRESHOLD

COMPARATOR

V

CC

Q5 Q6 Q7 Q8 Q9

THRESHOLD

TRIGGER

RESET

DISCHARGE

GND

Q1

2

4

7

Q14

1

4.7k

R1

Q2

Q15

RESET

S -8086

R2

R3

830Ω

Ω

Q3

R5

10kΩ

4.7k

Q4

Q10

100kΩ

Ω

R6

Q11 Q12

1k

R4

Ω

Q13

R7

100kΩ

S

CONTROL
VOLTAGE

5

R8

5k

Ω

R9

5kΩ

Q16 Q18

R10
5kΩ

R11
5kΩ

D2

Q17

Q19

R17

4.7k

Ω

R12

6.8kΩ

Q20

Q23

R16

100Ω

Q21

3.9kΩ

D1

R15

4.7k

OUTPUT

Ρ13

R14

220

Ω

Ω

Q22

3

Q24

TRIGGER COMPARATOR F LIP FLOP

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

T

T

2/10

Supply Voltage 18 V

cc

Operating Free Air Temperature Range for NE555

oper

for SA555
for SE555

T

Junction Temperature 150

j

Storage Temperature Range –65 to 150

stg

0to70
–40 to 105
–55 to 125

o

C

o

C

o

C

NE 555/SA 555/S E 555

OPERATINGCONDITIONS

Symbol Parameter SE555 NE555 - SA555 Unit

V

CC

V

th,Vtrig,Vcl,Vreset

ELECTRICAL CHARACTERISTICS

= +25oC, VCC= +5V to +15V (unless otherwisespecified)

T

amb

Symbol Parameter

I

V

V

V

I

V

V

Notes : 1. Supply current whenoutput is high is typically1mA less.

Supply Current (RL∞) (- note 1)

CC

Low State V
High State V

Timing Error (monostable)
(R

A=

Initial Accuracy - (note 2)
Drift with Temperature
Drift with Supply Voltage

Timing Error (astable)
(R

A,RB

V

CC

Initial Accuracy - (note 2)
Drift with Temperature
Drift with Supply Voltage

Control Voltage level

CL

Threshold Voltage

V

th

Threshold Current - (note 3) 0.1 0.25 0.1 0.25 µA

I

th

Trigger Voltage

trig

Trigger Current (V

I

trig

Reset Voltage - (note 4) 0.4 0.7 1 0.4 0.7 1 V

reset

Reset Current

reset

Low Level Output Voltage

OL

V

CC

V

CC

High Level Output Voltage

OH

V

CC

V

CC

2. Tested at V

3. This willdetermine the maximum value of R
the max total R = 3.5MΩ.

Supply Voltage 4.5 to 18 4.5 to 18 V
Maximum Input Voltage V

CC

V

CC

SE555 NE555 - SA555

Min. Typ. Max. Min. Typ. Max.

V

CC
CC
CC

=+5V
= +15V
=5V

10

3
2

12

5

3

10

2

2k to 100kΩ, C = 0.1µF)

0.5
30

0.05

2

100

0.2

1

50

0.1

=1kΩto 100kΩ, C = 0.1µF,

= +15V)

= +15V, I

= +5V, I

= +15V, I
= +5V, I

= +5V and VCC= +15V.

CC

1.5
90

0.15

= +15V

V

CC

=+5V

V

CC

= +15V

V

CC

=+5V

V

CC

= +15V

V

CC

=+5V

V

CC

= 0V) 0.5 0.9 0.5 2.0 µA

trig

= +0.4V

V

reset

=0V

V

reset

= 10mA

O(sink)

= 50mA

I

O(sink)

= 100mA

I

O(sink)

= 200mA

I

O(sink)

= 8mA

O(sink)

= 5mA

I

O(sink)

O(source)

I

O(source)
O(source)

= 200mA
= 100mA
= 100mA

A+RB

9.6

2.9

9.4

2.7

4.8

1.4551.67

13

3

for +15V operation themax total is R = 20MΩ and for 5V operation

10

3.33

10

3.33

0.1

0.4

0.1

0.4

2

2.5

0.1

0.05

12.5

13.3

3.3

10.4

3.8

10.6
4

5.2

1.9

0.4
1

0.15

0.5

2.2

0.25

0.2

2.6

8.8

2.4

4.5

1.1

12.75

2.75

2.25
150

0.3

9

10

3.33

10

3.33

5

1.67

0.1

0.4

0.1

0.4
2

2.5

0.3

0.25

12.5

13.3

3.3

6

15

3

0.5

11

4

11.2

4.2

5.6

2.2

0.4

1.5

0.25

0.75

2.5

0.4

0.35

V

Unit

mA

%

ppm/°C

%/V

%

ppm/°C

%/V

V

V

V

mA

V

V

3/10

NE 555/SA555/SE555

ELECTRICAL CHARACTERISTICS (continued)

Symbol Parameter

I

dis(off)

V

dis(sat)

Notes : 5. No protection against excessive Pin 7 current isnecessary, providing the package dissipation rating will notbe exceeded.

Discharge Pin Leakage Current
(output high) (V

dis

= 10V)

Discharge pin Saturation Voltage
(output low) - (note 5)

= +15V, I

V

CC

= +5V, I

V

CC

Output Rise Time

t

r

t

Output Fall Time

f

t

Turn off Time - (note 6) (V

off

6. Timemesaured from a positive going input pulse from 0 to 0.8x V
output trigger istied to treshold.

dis

= 4.5mA

dis

= 15mA

reset=VCC

) 0.5 0.5 µs

Min. Typ. Max. Min. Typ. Max.

SE555 NE555 - SA555

20 100 20 100 nA

180

80

100
100

CC

480
200

200
200

into the threshold to the drop from high to low of the

180

80

100
100

480
200

300
300

Unit

mV

ns

Figure1 : Minimum PulseWidth Requiredfor

Figure 2 : SupplyCurrent versusSupplyVoltage

Trigering

Figure 3 : DelayTime versusTemperature Figure4 : Low OutputVoltageversus Output

SinkCurrent

4/10

NE 555/SA 555/S E 555

Figure 5 : Low OutputVoltageversusOutput

SinkCurrent

Figure 7 : HighOutput VoltageDrop versus

Output

Figure 6 : LowOutput VoltageversusOutput

SinkCurrent

Figure 8 : DelayTime versusSupplyVoltage

Figure9 : PropagationDelay versusVoltage

Level of Trigger Value

5/10

NE 555/SA555/SE555

APPLICATION INFORMATI ON

MONOSTABLEOPERATION
In the monostable mode, the timer functions as a

one-shot.Referring tofigure10 theexternalcapaci­tor is initially held dischargedby a transistorinside
thetimer.

Figure10

V

= 5 to 15V

CC

Reset

R1

Trigger

Output

4

2

3

NE555

1

8

7

6

Control Voltage

5

0.01

C1

µF

Thecircuit triggerson a negative-goinginput signal
whenthelevelreaches1/3Vcc.Oncetriggered,the
circuit remains in this state until the set time has
elapsed,even if it is triggeredagain duringthis in­terval.ThedurationoftheoutputHIGHstateisgiven
by t = 1.1 R

andis easily determinedby

1C1

figure12.
Notice that since the chargerate and the threshold
levelofthecomparatorarebothdirectlyproportional
tosupply voltage,thetimingintervalis independent
ofsupply.Applyinga negativepulsesimultaneously
tothe resetterminal(pin 4) and the triggerterminal
(pin2) duringthe timingcycle dischargesthe exter­nalcapacitorandcausesthecycletostartover.The
timingcycle now startson thepositiveedgeof the
resetpulse. During the time the reset pulse in ap­plied,the output is drivento itsLOW state.
Whenanegativetriggerpulseisappliedtopin2,the
flip-flop isset, releasingthe short circuitacross the
externalcapacitoranddriving theoutputHIGH.The
voltage across the capacitor increases exponen­tiallywith thetimeconstantτ =R
ageacrossthecapacitorequals2/3V

. Whenthe volt-

1C1

,thecompa-

cc

ratorresetstheflip-flopwhichthendischargetheca­pacitor rapidly and drivers the output to its LOW
state.
Figure 11showstheactualwaveformsgeneratedin
thismode of operation.
When Reset is not used, it should be tied high to
avoidany possiblyor false triggering.

Figure 11

t = 0.1 ms / div

INPUT = 2.0V/div

OUTPUT VOLTAGE = 5.0V/div

CAPACITOR VOLTAGE = 2.0V/div

R1 = 9.1kΩ, C1 = 0.01µF, R = 1kΩ

L

Figure 12

C

(µF)

10

1.0

0.1

0.01

0.001
10 100 1.0 10 100 10 (t )

µs µs

Ω

R1= 1k

10kΩ

10

Ω

k

0

1MΩ

10M

ms ms ms s

Ω

d

ASTABLEOPERATION
Whenthe circuitis connectedasshownin figure13

(pin2and6connected)ittriggersitselfandfreeruns
as a multivibrator. The external capacitor charges
throughR

andR2and discharges throughR2only.

1

Thusthedutycyclemay bepreciselysetbythe ratio
of thesetworesistors.
In the astablemode of operation,C
dischargesbetween 1/3 V

and 2/3 Vcc. Asin the

cc

chargesand

1

triggeredmode,thechargeanddischargetimesand
thereforefrequencyare independentof the supply
voltage.

6/10

NE 555/SA 555/S E 555

Figure 13

VCC= 5 to 15V

R1

R2

C1

0.01

Output

µF

Control
Voltage

48

3

NE555

5

1

7

6

2

Figure14showsactualwaveformsgeneratedinthis
modeof operation.
Thecharge time(outputHIGH)is givenby :
t

=0.693 (R1+R2)C

1

1

andthe dischargetime (outputLOW) by :

=0.693 (R2)C

t

2

1

Thusthe total periodT isgivenby :
T=t

=0.693(R1+2R2)C

1+t2

1

Thefrequencyofoscillationis them :
f =

1
T

=

(R

1

1.44

+ 2R2) C

1

andmay beeasily foundby figure 15.
Theduty cycleis givenby :

R

D =

2

R1+ 2R

2

Figure 14

t = 0.5 ms / div

OUTPUT VOLTAGE= 5.0V/div

Figure 15 : Free RunningFrequencyversusR1,

andC

R

2

C

(µF)

10

1.0

0.1

0.01

0.001

R

1

+

0.1 1 10 100 1k 10k f (Hz)

1

1

k

Ω

1

0

k

Ω

1

0

0

k

1

Ω

M

R

Ω

2

=

1

0M

Ω

o

PULSEWIDTHMODULATOR
When the timer is connected in the monostable

mode and triggered with a continuouspulse train,
theoutputpulsewidthcanbemodulatedbyasignal
appliedto pin 5. Figure16 shows the circuit.

Figure 16 : Pulse Width Modulator.

V

CC

R

A

8

7

6

Modulation

Input

5

1

C

Trigger

Output

4

2

NE555

3

CAPACITOR VOLTAGE = 1.0V/div

R1 = R2 = 4.8kΩ, C1= 0.1µF, R = 1kΩ

L

7/10

NE 555/SA555/SE555

LINEARRAMP
Whenthe pullupresistor,R

, in themonostablecir-

A

cuitisreplacedbyaconstantcurrentsource,alinear
ramp is generated.Figure 17 shows a circuit con­figuration that will performthis function.

Figure17.

V

CC

R

E

R1

C

R2

Trigger

Output

NE555

1

8

7

2N4250

or equiv.

6

5

0.01µF

4

2

3

Figure 18showswaveformsgeneratorbythelinear
ramp.
Thetime intervalis given by :

T =

(2/3V

R

1VCC

RE(R

CC

1+

− VBE(R1+R

R

2)

C

VBE= 0.6V

2)

50%DUTY CYCLE OSCILLATOR
Fora 50% duty cycle the resistorsR

andREmay

A

beconnectedasin figure19.Thetimepreriodforthe
outputhigh is the sameas previous,

=0.693RAC.

t

1

For theoutputlow it ist
[(R

)⁄ (RA+ RB)] CLn

ARB

Thusthefrequencyof oscillationis f

=

2




2RB− R



RB− 2R



A



A



1

=

t

+ t

1

2

Notethat thiscircuit will not oscillateifRBisgreater
Figure 19 : 50%DutyCycleOscillator.

V

Out

CC

4

2

3

NE55

1

8

R

7

6

5

B

22kΩ

0.01µF

V

R

A

51kΩ

C

0.01µF

CC

Figure 18 : LinearRamp.

VCC= 5V Top trace : input 3V/DIV
Time = 20µs/DIV Middle trace : output 5V/DIV

= 47kΩ Bottom trace : output 5V/DIV

R

1

= 100kΩ Bottom trace : capacitor voltage

R

2

= 2.7kΩ 1V/DIV

R

E

C = 0.01µF

than1/2 R
notbringpin2 downto1/3V

becausethejunctionofRAand RBcan-

A

andtriggerthelower

CC

comparator.
ADDITIONALINFORMATION

Adequatepower supply bypassingis necessaryto
protect associated circuitry. Minimum recom­mendedis 0.1µF in parallel with 1µF electrolytic.

8/10

PACKAG E MECHANI CAL DATA

8 PINS - PLASTIC DIP

NE 555/SA 555/S E 555

Dimensions

Min. Typ. Max. Min. Typ. Max.

Millimeters Inches

A 3.32 0.131

a1 0.51 0.020

B 1.15 1.65 0.045 0.065
b 0.356 0.55 0.014 0.022

b1 0.204 0.304 0.008 0.012

D 10.92 0.430
E 7.95 9.75 0.313 0.384

e 2.54 0.100
e3 7.62 0.300
e4 7.62 0.300

F 6.6 0260

i 5.08 0.200
L 3.18 3.81 0.125 0.150
Z 1.52 0.060

PM-DIP8.EPS

DIP8.TBL

9/10

NE 555/SA555/SE555

PACKAG E MECHANI CAL DATA

8 PINS - P LASTIC MICROPACKAGE (SO)

Dimensions

Min. Typ. Max. Min. Typ. Max.

Millimeters Inches

A 1.75 0.069

a1 0.1 0.25 0.004 0.010
a2 1.65 0.065
a3 0.65 0.85 0.026 0.033

b 0.35 0.48 0.014 0.019

b1 0.19 0.25 0.007 0.010

C 0.25 0.5 0.010 0.020

c1 45

o

(typ.)
D 4.8 5.0 0.189 0.197
E 5.8 6.2 0.228 0.244
e 1.27 0.050

e3 3.81 0.150

F 3.8 4.0 0.150 0.157
L 0.4 1.27 0.016 0.050

M 0.6 0.024

S8

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consequences of use of such information nor for any infringement of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifi­cations mentioned in this publication are subject to change without notice. This publication supersedes and replaces all infor­mation previously supplied. STMicroelectronics products are not authorized for use as critical components in life support
devices or systems without express written approval of STMicroelectronics.

 The ST logois a trademark of STMicroelectronics

o

(max.)

PM-SO8.EPS

SO8.TBL

 1998 STMicroelectronics – Printed in Italy – All Rights Reserved

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10/10

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