Ne555

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LM555

Single Timer
Features
• • • • • High Current Drive Capability (200mA) Adjustable Duty Cycle Temperature Stability of 0.005%/C Timing From Sec to Hours Turn off Time Less Than 2Sec

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

Applications
• • • • Precision Timing Pulse Generation Time Delay Generation Sequential Timing

1

8-SOIC

1

Internal Block Diagram

R

R

R 8

GND

1

Vcc

Comp.

Trigger

Discharging Tr. 7

2

DischargeOutput

3

OutPut Stage

F/F

6 Comp.

Threshold Control Voltage

Reset

4

5

Vref

Rev. 1.0.5
©2012 Fairchild Semiconductor Corporation

LM555

Absolute Maximum Ratings (TA = 25C)
Parameter Supply Voltage Lead Temperature (Soldering 10sec) Power Dissipation Operating Temperature Range (LM555) Storage Temperature Range Symbol VCC TLEAD PD TOPR TSTG Value 16 300 600 0 ~+70 -65 ~ +150 Unit V C mW C C

2

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Electrical Characteristics
(TA = 25C, VCC = 5 ~ 15V, unless otherwise specified) Parameter Supply Voltage Supply Current (Low Stable) (Note1) Timing Error (Monostable) Initial Accuracy (Note2) Drift with Temperature (Note4) Drift with Supply Voltage (Note4) Timing Error (Astable) Intial Accuracy (Note2) Drift with Temperature (Note4) Driftwith Supply Voltage (Note4) Control Voltage Threshold Voltage Threshold Current (Note3) Trigger Voltage Trigger Current Reset Voltage Reset Current Symbol VCC ICC Conditions VCC = 5V, RL =  VCC = 15V, RL =  Min. 4.5 Typ. 3 7.5 Max. 16 6 15 Unit V mA mA

ACCUR t/T t/VCC

RA = 1k to100k C = 0.1F

-

1.0 50 0.1

3.0 0.5

% ppm/C %/V

ACCUR t/T t/VCC VC VTH ITH VTR ITR VRSTIRST

RA = 1k to 100k C = 0.1F VCC = 15V VCC = 5V VCC = 15V VCC = 5V VCC = 5V VCC = 15V VTR = 0V VCC = 15V ISINK = 10mA ISINK = 50mA VCC = 5V ISINK = 5mA VCC = 15V ISOURCE = 200mA ISOURCE = 100mA VCC = 5V ISOURCE = 100mA

-

2.25 150 0.3 10.0 3.33 10.0 3.33 0.1 1.67 5 0.01 0.7 0.1

-

% ppm/C %/V V V V V A V V A V mA V V V V V V ns ns nA

9.0 2.6 1.1 4.5 0.4

11.0 4.0 0.25 2.25.6 2.0 1.0 0.4 0.25 0.75 0.35 100

-

Low Output Voltage

VOL

0.06 0.3 0.05 12.5 13.3 3.3 100 100 20

High Output Voltage

VOH

12.75 2.75 -

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

tR tF ILKG

-

Notes: 1. When the output is high, the supply current is typically 1mA less than at VCC = 5V. 2. Tested at VCC = 5.0V and VCC = 15V. 3.This will determine the maximum value of RA + RB for 15V operation, the max. total R = 20M, and for 5V operation, the max. total R = 6.7M 4. These parameters, although guaranteed, are not 100% tested in production.

3

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Application Information
Table 1 below is the basic operating table of 555 timer: Table 1. Basic Operating Table Threshold Voltage Trigger Voltage Discharging Tr.Reset(PIN 4) Output(PIN 3) (Vth)(PIN 6) (Vtr)(PIN 2) (PIN 7) Don't care Don't care Low Low ON Vth > 2Vcc / 3 Vth > 2Vcc / 3 High Low ON Vcc / 3 < Vth < 2 Vcc / 3 Vcc / 3 < Vth < 2 Vcc / 3 High Vth < Vcc / 3 Vth < Vcc / 3 High High OFF 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 highsignal 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...