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(R)
NE555 SA555 - SE555
GENERAL PURPOSE SINGLE BIPOLAR TIMERS
.LOWTURNOFFTI .MAXI .TI .OPERATES .HI .ADJUSTABLEDUTYCYCLE .TTLCOMPATI .TEMPERATURE
BLE PERoC
ME MUM OPERATING FREQUENCY GREATER THAN 500kHz MING FROM MICROSECONDS TO HOURS IN BOTH ASTABLE AND MONOSTABLE MODES GH OUTPUT CURRENT CAN SOURCE OR SINK 200mA
STABILITY
OF
0.005%
DESCRIPTION The NE555 monolithic timing circuit is a highly stable controller capableof producing accuratetime delays or oscillation. In the time delay mode of operation, the time is precisely controlled by one external resistor and capacitor.For a stableoperation as an oscillator, the free running frequency and the duty cycle are both accurately controlled with two external resistors and one capacitor. The circuit may be triggered and reset on falling waveforms, and the output structure can source or sink up to 200mA. The NE555 is available in plastic and ceramic minidip package and in a 8-lead micropackage and in metal can package version. PIN CONNECTIONS (top view)
N DIP8 (Plastic Package)
D SO8 (Plastic Micropackage)
ORDER CODES
Part Number NE555 SA555 SE555 Temperature Range 0oC, 70oC -40 C, 105 C -55 C, 125 C
o o o o
Package N * * * D * * *
1 2 3 4
8 7 6 5
1 2 3 4 5 6 7 8
- GND - Trigger - Output - Reset - Control voltage - Threshold - Discharge - VCC
July 1998
1/10
NE555/SA555/SE555
BLOCK DIAGRAM
VCC+
5k COMP THRESHOLD CONTROL VOLTAGE R FLIP-FLOP 5k COMP TRIGGER
DISCHARGE
Q OUT S INHIBIT/ RESET
5k
RESET
S
S - 808 6
SCHEMATIC DIAGRAM
CONTROL VOLTAGE THRESHOLD COMPARATOR 5 R1 4.7k R2 830 R3 4.7k OUTPUT
VCC
R4 R8 1k 5k
R12 6.8k
Q21 Q19 Q20 Q22
Q5
Q6
Q7
Q8
Q9
13
R11 5k THRESHOLD Q1 Q2 Q3 Q11 Q12 TRIGGER 2 Q10 Q4 3.9k 3
R17 4.7k
Q23
D1
R9 5k
Q13 Q16
D2
R14 220
Q24
Q18
R16 100
R15 4.7k
RES ET DISCHARGE
4 7 Q14 1
Q15 Q17 R5 10k R6 100k R7 100k
R10 5k
G ND
TRIGGER COMPARATOR
FLIP FLOP
ABSOLUTE MAXIMUM RATINGS
Symbol Vcc Toper Supply Voltage Operating Free Air Temperature Range for NE555 for SA555 for SE555 Parameter Value 18 0 to 70 -40 to 105 -55 to 125 150 -65 to 150 Unit V
o
C
Tj Tstg
Junction Temperature Storage Temperature Range
o o
C C
2/10
NE555/SA555/SE555
OPERATING CONDITIONS
Symbol VCC Vth, Vtrig, Vcl, Vreset Supply Voltage Maximum Input Voltage Parameter SE555 4.5 to 18 VCC NE555 - SA555 4.5 to 18 VCC Unit V V
ELECTRICAL CHARACTERISTICS T amb = +25oC, VCC = +5V to +15V (unless otherwise specified)
Symbol ICC Parameter Supply Current (RL ) (- note 1) Low State VCC = +5V VCC = +15V High State VCC = 5V Timing Error (monostable) (RA = 2k to 100k, C = 0.1F) Initial Accuracy - (note 2) Drift with Temperature Drift with Supply Voltage Timing Error (astable) (RA, RB = 1k to 100k, C = 0.1F, VCC = +15V) Initial Accuracy - (note 2) Drift with Temperature Drift with Supply Voltage VCL Control Voltage level VCC = +15V VCC = +5V Threshold Voltage VCC = +15V VCC = +5V Threshold Current - (note 3) Trigger Voltage VCC = +15V VCC = +5V Trigger Current (Vtrig = 0V) Reset Voltage - (note 4) Reset Current Vreset = +0.4V Vreset = 0V VOL Low Level Output Voltage VCC = +15V, IO(sink) = 10mA IO(sink) = 50mA IO(sink) = 100mA IO(sink) = 200mA VCC = +5V, IO(sink) = 8mA IO(sink) = 5mA High Level Output Voltage VCC = +15V, IO(source) = 200mA IO(source) = 100mA VCC = +5V, IO(source) = 100mA 0.1 0.4 0.1 0.4 2 2.5 0.1 0.05 12.5 13.3 3.3 0.4 1 0.15 0.5 2.2 0.25 0.2 0.1 0.4 0.1 0.4 2 2.5 0.3 0.25 12.5 13.3 3.3 0.4 1.5 V 0.25 0.75 2.5 0.4 0.35 V 13 3 12.75 2.75 0.4 4.8 1.45 9.6 2.9 9.4 2.7 SE555 Min. Typ. 3 10 2 Max. 5 12 NE555 - SA555 Min. Typ. 3 10 2 Max. 6 15 Unit mA
0.5 30 0.05
2 100 0.2
1 50 0.1
3 0.5
% ppm/C %/V
1.5 90 0.15 10 3.33 10 3.33 0.1 5 1.67 0.5 0.7 10.4 3.8 10.6 4 0.25 5.2 1.9 0.9 1 0.4 4.5 1.1 9 2.6 8.8 2.4
2.25 150 0.3 10 3.33 10 3.33 0.1 5 1.67 0.5 0.7 11 4
% ppm/C %/V V
Vth
V 11.2 4.2 0.25 5.6 2.2 2.0 1 A V mA A V
Ith Vtrig
Itrig Vreset Ireset
VOH
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 = 20M and for 5V operation the max total R = 3.5M.
3/10
NE555/SA555/SE555
ELECTRICAL CHARACTERISTICS (continued)
Symbol Idis (off) Vdis(sat) Parameter Discharge Pin Leakage Current (output high) (Vdis = 10V) Discharge pin Saturation Voltage (output low) - (note 5) VCC = +15V, Idis = 15mA VCC = +5V, Idis = 4.5mA Output Rise Time Output Fall Time Turn off Time - (note 6) (Vreset = VCC) SE555 Min. Typ. 20 Max. 100 NE555 - SA555 Min. Typ. 20 Max. 100 Unit nA mV 180 80 100 100 0.5 480 200 200 200 180 80 100 100 0.5 480 200 300 300 ns s
tr tf toff
Notes :
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 the output trigger is tied to treshold.
Figure 1 : Minimum Pulse Width Required for Trigering
Figure 2 : Supply Current versus Supply Voltage
Figure 3 : Delay Time versus Temperature
Figure 4 : Low Output Voltage versus Output Sink Current
4/10
NE555/SA555/SE555
Figure 5 : Low Output Voltage versus Output Sink Current Figure 6 : Low Output Voltage versus Output Sink Current
Figure 7 : High Output Voltage Drop versus Output
Figure 8 : Delay Time versus Supply Voltage
Figure 9 : Propagation Delay versus Voltage Level of Trigger Value
5/10
NE555/SA555/SE555
APPLICATION INFORMATION MONOSTABLE OPERATION In the monostable mode, the timer functions as a one-shot. Referring to figure 10 the external capacitor is initially held discharged by a transistor inside the timer. Figure 10
VCC = 5 to 15V
Figure 11
t = 0.1 ms / div INPUT = 2.0V/div
OUTPUT VOLTAGE = 5.0V/div
Reset
R1
4 Trigger 2
8
7
NE555
Output
6
C1
CAPACITOR VOLTAGE = 2.0V/div
3 1
5
Control Voltage 0.01F
R1 = 9.1k, C1 = 0.01F, RL = 1k Figure 12
The circuit triggers on a negative-going input signal when the level reaches 1/3 Vcc. Once triggered, the circuit remains in this state until the set time has elapsed, even if it is triggered again during this interval.The duration of the output HIGH stateis given by t = 1.1 R1C1 and is easily determined by figure 12. Notice that since the charge rate and the threshold level of the comparator are both directly proportional to supply voltage, the timing interval is independent of supply. Applying a negativepulse simultaneously to the reset terminal (pin 4) and the trigger terminal (pin 2) during the timing cycle discharges the external capacitor and causes the cycle to start over. The timing cycle now starts on the positive edge of the reset pulse. During the time the reset pulse in applied, the output is driven to its LOW state. When a negativetrigger pulse is applied to pin 2, the flip-flop is set, releasing the short circuit across the external capacitor and driving the output HIGH. The voltage across the capacitor increases exponentially with the time constant = R1C1. When the voltage across the capacitor equals 2/3 Vcc, the comparatorresets the flip-flop which then discharge the capacitor rapidly and drivers the output to its LOW state. Figure 11 shows the actual waveforms generatedin this mode of operation. When Reset is not used, it should be tied high to avoid any possibly or false triggering.
6/10
C (F) 10
1k 10 k
1.0 0.1 0.01 0.001 10 s
10 0k 1M
10 ms
R 1=
100 ms
100 s
1.0 ms
10 M
10 s
(t d )
ASTABLE OPERATION When the circuit is connected as shown in figure 13 (pin 2 and 6 connected)it triggers itself and free runs as a multivibrator. The external capacitor charges through R1 and R2 and discharges through R2 only. Thus the duty cycle may be precisely set by the ratio of these two resistors. In the astable mode of operation, C1 charges and discharges between 1/3 Vcc and 2/3 Vcc. As in the triggeredmode, the chargeand discharge times and therefore frequency are independent of the supply voltage.
NE555/SA555/SE555
Figure 13
VCC = 5 to 15V
Figure 15 : Free Running Frequency versus R1, R2 and C1
R1 4 Output 3 8
7
C (F) 10 1.0 0.1
NE555
Control Voltage 0.01F 5 1 2 6
R2
R1
+
R2
1M
10
=
0k
1k 10 k
C1
0.01 0.001 0.1
10 M
100 1k 10k f o (Hz)
Figure 14 shows actual waveforms generatedin this mode 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 : 1 1.44 f= = T (R1 + 2R2) C1 and may be easily found by figure 15. The duty cycle is given by : R2 D= R1 + 2R2
1
10
PULSE WIDTH MODULATOR When the timer is connected in the monostable mode and triggered with a continuous pulse train, the output pulse width can be modulated by a signal applied to pin 5. Figure 16 shows the circuit. Figure 16 : Pulse Width Modulator.
VCC RA
4
8 7
Figure 14
t = 0.5 ms / div
Trigger
2
NE555
OUTPUT VOLTAGE = 5.0V/div
Output 3 1
6 Modulation Input
5
C
CAPACITOR VOLTAGE = 1.0V/div
R1 = R2 = 4.8k, C1= 0.1F, RL = 1k
7/10
NE555/SA555/SE555
LINEAR RAMP When the pullup resistor, RA, in the monostable circuit is replaced by a constant current source, a linear ramp is generated. Figure 17 shows a circuit configuration that will perform this function. Figure 17. 50% DUTY CYCLE OSCILLATOR For a 50% duty cycle the resistors RA and RE may beconnected as in figure19. The time preriod for the output high is the same as previous, t1 = 0.693 RA C. For the output low it is t2 = RB - 2RA [(RARB) (RA + RB)] CLn 2RB - RA t1 + t2 Note that this circuit will not oscillate if RB is greater Figure 19 : 50% Duty Cycle Oscillator.
2N4250 or equiv. 6 C
Output 3 1 5
VCC RE
4 Trigger 2
Thus the frequency of oscillation is f =
1
R1
8 7
NE555
VCC
VCC
R2 0.01F 4 2
RA 51k 8 RB 7 22k
NE55
Figure 18 shows waveforms generator by the linear ramp. The time interval is given by : (2/3 VCC RE (R1+ R2) C T= VBE = 0.6V R1 VCC - VBE (R1+ R2) Figure 18 : Linear Ramp.
Out 3 1
6
5
0.01F C 0.01F
than 1/2 RA because the junction of RA and RB cannot bring pin 2 down to 1/3 VCC and trigger the lower comparator. ADDITIONAL INFORMATION Adequate power supply bypassing is necessary to protect associated circuitry. Minimum recommended is 0.1F in parallel with 1F electrolytic.
VCC = 5V Time = 20s/DIV R 1 = 47k R 2 = 100k R E = 2.7k C = 0.01F
Top trace : input 3V/DIV Middle trace : output 5V/DIV Bottom trace : output 5V/DIV Bottom trace : capacitor voltage 1V/DIV
8/10
NE555/SA555/SE555
PACKAGE MECHANICAL DATA 8 PINS - PLASTIC DIP
Dimensions A a1 B b b1 D E e e3 e4 F i L Z
Min. 0.51 1.15 0.356 0.204 7.95
Millimeters Typ. 3.32
Max.
Min. 0.020 0.045 0.014 0.008 0.313
Inches Typ. 0.131
Max.
1.65 0.55 0.304 10.92 9.75 2.54 7.62 7.62 6.6 5.08 3.81 1.52
0.065 0.022 0.012 0.430 0.384 0.100 0.300 0.300 0260 0.200 0.150 0.060
9/10
DIP8.TBL
3.18
0.125
PM-DIP8.EPS
NE555/SA555/SE555
PACKAGE MECHANICAL DATA 8 PINS - PLASTIC MICROPACKAGE (SO)
Dimensions A a1 a2 a3 b b1 C c1 D E e e3 F L M S
Min. 0.1 0.65 0.35 0.19 0.25 4.8 5.8
Millimeters Typ.
Max. 1.75 0.25 1.65 0.85 0.48 0.25 0.5 45 (typ.) 5.0 6.2
o
Min. 0.004 0.026 0.014 0.007 0.010 0.189 0.228
Inches Typ.
Max. 0.069 0.010 0.065 0.033 0.019 0.010 0.020 0.197 0.244
1.27 3.81 3.8 0.4 4.0 1.27 0.6 8 (max.)
o
0.050 0.150 0.150 0.016 0.157 0.050 0.024
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the 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 pub lication 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. (c) The ST log o is a trademark of STMicroelectronics (c) 1998 STMicroelectronics - Printed in Italy - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - France - Germany - Italy - Japan - Korea - Malaysia - Malta - Mexico - Morocco The Netherlands - Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdo m - U.S.A.
ORDER CODE :
10/10
SO8.TBL
PM-SO8.EPS

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