2182.pdf
DESCRIPTION
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July 1998
®
NDIP8
(Plastic Package)
DSO8
(Plastic Micropackage)
1
2
3
4 5
6
7
8 1 - GND2 - Trigger3 - Output4 - Reset5 - Control voltage6 - Threshold7 - Discharge8 - VCC
PIN CONNECTIONS (top view)
. LOW TURN OFF TIME.MAXIMUM OPERATING FREQUENCYGREATER THAN 500kHz.TIMING FROM MICROSECONDS TO HOURS.OPERATES IN BOTH ASTABLE ANDMONOSTABLE MODES.HIGH OUTPUT CURRENT CAN SOURCE ORSINK 200mA.ADJUSTABLE DUTY CYCLE.TTL COMPATIBLE.TEMPERATURE STABILITY OF 0.005%PERoC
ORDER CODES
PartNumber
TemperatureRange
Package
N D
NE555 0oC, 70oC • •SA555 –40oC, 105oC • •SE555 –55oC, 125oC • •
DESCRIPTION
The NE555 monolithic timing circuit is a highly stablecontroller capable of producing accurate time delaysor oscillation. In the time delay mode of operation,the time is precisely controlled by one external re-sistor and capacitor. For a stable operation as an os-cillator, the free running frequency and the duty cy-cle are both accurately controlled with two externalresistors and one capacitor. The circuit may be trig-gered and reset on falling waveforms, and the out-put structure can source or sink up to 200mA. TheNE555 is available in plastic and ceramic minidippackage and in a 8-lead micropackage and in metalcan package version.
NE555SA555 - SE555
GENERAL PURPOSE SINGLE BIPOLAR TIMERS
1/10
THRESHOLD
COMP
5kΩ
5kΩ
5kΩ
TRIGGER
R
FLIP-FLOP
S
Q
DISCHARGE
OUT
INHIBIT/
RESET
RESET
COMP
S - 8086
S
+
CONTROL VOLTAGE
VCC
BLOCK DIAGRAM
OUTPUT
CONTROLVOLTAGE
THRESHOLDCOMPARATOR
VCC
R14.7kW
R2830W
Q5 Q6 Q7 Q8 Q9
R34.7kW
R41kW
R85kW
Q1
Q2 Q3
Q4
Q10
Q11 Q12
Q13
THRESHOLD
TRIGGER
RESET
DISCHARGE
G N D
2
4
7
1
Q14
Q15
R510kW
R6100kW
R7100kW
R105kW
Q17
Q16 Q18
R95kW D2
R16100W
R154.7kW
R14220W
Q24
Q23
R174.7kW
3
Q22
R13
D1
Q19Q20
Q21
R126.8kW
5
TRIGGER COMPARATOR FLIP FLOP
R115kW
3.9kW
SCHEMATIC DIAGRAM
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
Vcc Supply Voltage 18 V
Toper Operating Free Air Temperature Range for NE555for SA555for SE555
0 to 70–40 to 105–55 to 125
oC
Tj Junction Temperature 150 oC
Tstg Storage Temperature Range –65 to 150 oC
NE555/SA555/SE555
2/10
ELECTRICAL CHARACTERISTICSTamb = +25oC, VCC = +5V to +15V (unless otherwise specified)
Symbol ParameterSE555 NE555 - SA555
UnitMin. Typ. Max. Min. Typ. Max.
ICC Supply Current (RL ∞) (- note 1)Low State VCC = +5V
VCC = +15VHigh State VCC = 5V
3102
512
3102
615
mA
Timing Error (monostable)(RA = 2k to 100kΩ, C = 0.1µF)Initial Accuracy - (note 2)Drift with TemperatureDrift with Supply Voltage
0.530
0.05
21000.2
1500.1
3
0.5
%ppm/°C
%/V
Timing Error (astable)(RA, RB = 1kΩ to 100kΩ, C = 0.1µF,VCC = +15V) Initial Accuracy - (note 2)Drift with TemperatureDrift with Supply Voltage
1.590
0.15
2.251500.3
%ppm/°C
%/V
VCL Control Voltage levelVCC = +15VVCC = +5V
9.62.9
103.33
10.43.8
92.6
103.33
114
V
Vth Threshold VoltageVCC = +15VVCC = +5V
9.42.7
103.33
10.64
8.82.4
103.33
11.24.2
V
Ith Threshold Current - (note 3) 0.1 0.25 0.1 0.25 µA
Vtrig Trigger VoltageVCC = +15VVCC = +5V
4.81.45
51.67
5.21.9
4.51.1
51.67
5.62.2
V
Itrig Trigger Current (Vtrig = 0V) 0.5 0.9 0.5 2.0 µA
Vreset Reset Voltage - (note 4) 0.4 0.7 1 0.4 0.7 1 V
Ireset Reset CurrentVreset = +0.4VVreset = 0V
0.10.4
0.41
0.10.4
0.41.5
mA
VOL Low Level Output VoltageVCC = +15V, IO(sink) = 10mA
IO(sink) = 50mAIO(sink) = 100mAIO(sink) = 200mA
VCC = +5V, IO(sink) = 8mAIO(sink) = 5mA
0.10.42
2.50.1
0.05
0.150.52.2
0.250.2
0.10.42
2.50.3
0.25
0.250.752.5
0.40.35
V
VOH High Level Output VoltageVCC = +15V, IO(source) = 200mA
IO(source) = 100mAVCC = +5V, IO(source) = 100mA
133
12.513.33.3
12.752.75
12.513.33.3
V
Notes : 1. Supply current when output is high is typically 1mA less.2. Tested at VCC = +5V and VCC = +15V.3. This will determine the maximum value of RA + RB for +15V operation the max total is R = 20MΩ and for 5V operation
the max total R = 3.5MΩ.
OPERATING CONDITIONS
Symbol Parameter SE555 NE555 - SA555 Unit
VCC Supply Voltage 4.5 to 18 4.5 to 18 V
Vth, Vtrig, Vcl, Vreset Maximum Input Voltage VCC VCC V
NE555/SA555/SE555
3/10
ELECTRICAL CHARACTERISTICS (continued)
Symbol ParameterSE555 NE555 - SA555
UnitMin. Typ. Max. Min. Typ. Max.
Idis(off) Discharge Pin Leakage Current(output high) (Vdis = 10V)
20 100 20 100 nA
Vdis(sat) Discharge pin Saturation Voltage(output low) - (note 5)VCC = +15V, Idis = 15mAVCC = +5V, Idis = 4.5mA
18080
480200
18080
480200
mV
trtf
Output Rise TimeOutput Fall Time
100100
200200
100100
300300
ns
toff Turn off Time - (note 6) (Vreset = VCC) 0.5 0.5 µsNotes : 5. No protection against excessive Pin 7 current is necessary, providing the package dissipation rating will not be exceeded.
6. Time mesaured from a positive going input pulse from 0 to 0.8x VCC into the threshold to the drop from high to low of theoutput trigger is tied to treshold.
Figure 1 : Minimum Pulse Width Required forTrigering
Figure 2 : Supply Current versus Supply Voltage
Figure 3 : Delay Time versus Temperature Figure 4 : Low Output Voltage versus OutputSink Current
NE555/SA555/SE555
4/10
Figure 5 : Low Output Voltage versus OutputSink Current
Figure 6 : Low Output Voltage versus OutputSink Current
Figure 7 : High Output Voltage Drop versusOutput
Figure 8 : Delay Time versus Supply Voltage
Figure 9 : Propagation Delay versus VoltageLevel of Trigger Value
NE555/SA555/SE555
5/10
CAPACITOR VOLTAGE = 2.0V/div
t = 0.1 ms / div
INPUT = 2.0V/div
OUTPUT VOLTAGE = 5.0V/div
R1 = 9.1kΩ, C1 = 0.01µF, R = 1kΩL
Figure 11
Reset
Trigger
Output
R1
C1
Control Voltage
0.01µF
NE555
= 5 to 15VVCC
4
2
3
1
5
6
7
8
Figure 10
C(µF)10
1.0
0.1
0.01
0.00110 100 1.0 10 100 10 (t )dµs µs ms ms ms s
10M
Ω1MΩ10
0kΩ10
kΩR1= 1
kΩ
Figure 12
APPLICATION INFORMATION
MONOSTABLE OPERATIONIn the monostable mode, the timer functions as aone-shot. Referring to figure 10 the external capaci-tor is initially held discharged by a transistor insidethe timer.
The circuit triggers on a negative-going input signalwhen the level reaches 1/3 Vcc. Once triggered, thecircuit remains in this state until the set time haselapsed, even if it is triggered again during this in-terval. The duration of the output HIGH state is givenby t = 1.1 R1C1 and is easily determined by figure 12.Notice that since the charge rate and the thresholdlevel of the comparator are both directly proportionalto supply voltage, the timing interval is independentof supply. Applying a negative pulse simultaneouslyto the reset terminal (pin 4) and the trigger terminal(pin 2) during the timing cycle discharges the exter-nal capacitor and causes the cycle to start over. Thetiming cycle now starts on the positive edge of thereset pulse. During the time the reset pulse in ap-plied, the output is driven to its LOW state.When a negative trigger pulse is applied to pin 2, theflip-flop is set, releasing the short circuit across theexternal capacitor and driving the output HIGH. Thevoltage across the capacitor increases exponen-tially with the time constant τ = R1C1. When the volt-age across the capacitor equals 2/3 Vcc, the compa-rator resets the flip-flop which then discharge the ca-pacitor rapidly and drivers the output to its LOWstate.Figure 11 shows the actual waveforms generated inthis mode of operation.When Reset is not used, it should be tied high toavoid any possibly or false triggering.
ASTABLE OPERATIONWhen the circuit is connected as shown in figure 13(pin 2 and 6 connected) it triggers itself and free runsas a multivibrator. The external capacitor chargesthrough R1 and R2 and discharges through R2 only.Thus the duty cycle may be precisely set by the ratioof these two resistors.In the astable mode of operation, C1 charges anddischarges between 1/3 Vcc and 2/3 Vcc. As in thetriggered mode, the charge and discharge times andtherefore frequency are independent of the supplyvoltage.
NE555/SA555/SE555
6/10
t = 0.5 ms / div
OUTPUT VOLTAGE = 5.0V/div
CAPACITOR VOLTAGE = 1.0V/div
R1 = R2 = 4.8kΩ, C1= 0.1µF, R = 1kΩL
Figure 14
C(µF)10
1.0
0.1
0.01
0.0010.1 1 10 100 1k 10k f (Hz)o
1MΩ
R1 + R2 = 10MΩ
100kΩ
10kΩ
1kΩ
Figure 15 : Free Running Frequency versus R1,R2 and C1
Figure 14 shows actual waveforms generated in thismode of operation.The charge time (output HIGH) is given by :t1 = 0.693 (R1 + R2) C1
and the discharge time (output LOW) by :t2 = 0.693 (R2) C1
Thus the total period T is given by :T = t1 + t2 = 0.693 (R1 + 2R2) C1
The frequency ofoscillation is them :
f = 1T
= 1.44
(R1 + 2R2) C1
and may be easily found by figure 15.The duty cycle is given by :
D = R2
R1 + 2R2
Output 3
4 8
7
5
1
R1
C12
6
R2
ControlVoltage
NE555
VCC = 5 to 15V
0.01µF
Figure 13
PULSE WIDTH MODULATORWhen the timer is connected in the monostablemode and triggered with a continuous pulse train,the output pulse width can be modulated by a signalapplied to pin 5. Figure 16 shows the circuit.
Trigger
Output
R
C
NE555
2
4
3
1
5
6
7
ModulationInput
8
A
VCC
Figure 16 : Pulse Width Modulator.
NE555/SA555/SE555
7/10
LINEAR RAMPWhen the pullup resistor, RA, in the monostable cir-cuit is replaced by a constant current source, a linearramp is generated. Figure 17 shows a circuit con-figuration that will perform this function.
Trigger
Output
C
NE555
2
4
3
1
5
6
7
8
E
VCC
0.01µFR2
R1R
2N4250or equiv.
Figure 17.
Out
RA
C
NE55
2
4
3
1
5
6
7
8
VCC
51kΩ
RB
22kΩ
0.01µF
VCC
0.01µF
Figure 19 : 50% Duty Cycle Oscillator.
Figure 18 shows waveforms generator by the linearramp.The time interval is given by :
T = (2/3 VCC RE (R1+ R2) CR1 VCC − VBE (R1+ R2)
VBE = 0.6V
Figure 18 : Linear Ramp.
VCC = 5V Top trace : input 3V/DIVTime = 20µs/DIV Middle trace : output 5V/DIVR1 = 47kΩ Bottom trace : output 5V/DIVR2 = 100kΩ Bottom trace : capacitor voltageRE = 2.7kΩ 1V/DIVC = 0.01µF
50% DUTY CYCLE OSCILLATORFor a 50% duty cycle the resistors RA and RE maybe connected as in figure 19. The time preriod for theoutput high is the same as previous,t1 = 0.693 RA C.For the output low it is t2 =
[(RARB) ⁄ (RA + RB)] CLn RB − 2RA
2RB − RA
Thus the frequency of oscillation is f = 1t1 + t2
Note that this circuit will not oscillate if RB is greater
than 1/2 RA because the junction of RA and RB can-not bring pin 2 down to 1/3 VCC and trigger the lowercomparator.
ADDITIONAL INFORMATIONAdequate power supply bypassing is necessary toprotect associated circuitry. Minimum recom-mended is 0.1µF in parallel with 1µF electrolytic.
NE555/SA555/SE555
8/10
PM
-DIP
8.E
PS
PACKAGE MECHANICAL DATA8 PINS - PLASTIC DIP
DimensionsMillimeters Inches
Min. Typ. Max. Min. Typ. Max.A 3.32 0.131a1 0.51 0.020B 1.15 1.65 0.045 0.065b 0.356 0.55 0.014 0.022
b1 0.204 0.304 0.008 0.012D 10.92 0.430E 7.95 9.75 0.313 0.384e 2.54 0.100
e3 7.62 0.300e4 7.62 0.300F 6.6 0260i 5.08 0.200L 3.18 3.81 0.125 0.150Z 1.52 0.060
DIP
8.T
BL
NE555/SA555/SE555
9/10
PM
-SO
8.E
PS
PACKAGE MECHANICAL DATA8 PINS - PLASTIC MICROPACKAGE (SO)
DimensionsMillimeters Inches
Min. Typ. Max. Min. Typ. Max.A 1.75 0.069a1 0.1 0.25 0.004 0.010a2 1.65 0.065a3 0.65 0.85 0.026 0.033b 0.35 0.48 0.014 0.019
b1 0.19 0.25 0.007 0.010C 0.25 0.5 0.010 0.020c1 45o (typ.)D 4.8 5.0 0.189 0.197E 5.8 6.2 0.228 0.244e 1.27 0.050
e3 3.81 0.150F 3.8 4.0 0.150 0.157L 0.4 1.27 0.016 0.050M 0.6 0.024S 8o (max.)
SO
8.TB
L
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for theconsequences of use of such information nor for any infringement of patents or other rights of third parties which may resultfrom its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specif i-cations mentioned in this publication are subject to change without notice. This publication supersedes and replaces all infor-mation previously supplied. STMicroelectronics products are not authorized for use as critical components in life supportdevices or systems without express written approval of STMicroelectronics.
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© 1998 STMicroelectronics – Printed in Italy – All Rights ReservedSTMicroelectronics GROUP OF COMPANIES
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RD
ER
CO
DE
:
NE555/SA555/SE555
10/10
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