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LM555 Timer

July 2006

LM555 Timer
General Description
The LM555 is a highly stable device for generating accurate time delays or oscillation. Additional terminals are provided for triggering or resetting if desired. In the time delay mode of operation, the time is precisely controlled by one external resistor and capacitor. For astable operation as an oscillator, the free runningfrequency and duty cycle are accurately controlled with two external resistors and one capacitor. The circuit may be triggered and reset on falling waveforms, and the output circuit can source or sink up to 200mA or drive TTL circuits.

n n n n n n n n n Direct replacement for SE555/NE555 Timing from microseconds through hours Operates in both astable and monostable modes Adjustable duty cycleOutput can source or sink 200 mA Output and supply TTL compatible Temperature stability better than 0.005% per ˚C Normally on and normally off output Available in 8-pin MSOP package

n n n n n n n Precision timing Pulse generation Sequential timing Time delay generation Pulse width modulation Pulse position modulation Linear ramp generator

Schematic Diagram


©2006 National Semiconductor Corporation



Connection Diagram
Dual-In-Line, Small Outline and Molded Mini Small Outline Packages


Top View

Ordering Information
Package 8-Pin SOIC 8-Pin MSOP 8-Pin MDIP Part Number LM555CM LM555CMX LM555CMM LM555CMMX LM555CN Package Marking LM555CM LM555CM Z55 Z55 LM555CN Media Transport Rails 2.5k Units Tapeand Reel 1k Units Tape and Reel 3.5k Units Tape and Reel Rails NSC Drawing M08A MUA08A N08E



Absolute Maximum Ratings (Note 2)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage Power Dissipation (Note 3) LM555CM, LM555CN LM555CMMOperating Temperature Ranges LM555C Storage Temperature Range 0˚C to +70˚C −65˚C to +150˚C 1180 mW 613 mW +18V

Soldering Information Dual-In-Line Package Soldering (10 Seconds) Small Outline Packages (SOIC and MSOP) Vapor Phase (60 Seconds) Infrared (15 Seconds) 215˚C 220˚C 260˚C

See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” for other methods of soldering surfacemount devices.

Electrical Characteristics (Notes 1, 2)
(TA = 25˚C, VCC = +5V to +15V, unless othewise specified) Parameter Conditions Min Supply Voltage Supply Current VCC = 5V, RL = ∞ VCC = 15V, RL = ∞ (Low State) (Note 4) 4.5 3 10 Limits LM555C Typ Max 16 6 15 V mA Units

Timing Error, Monostable Initial Accuracy Drift with Temperature Accuracy over Temperature Drift with Supply TimingError, Astable Initial Accuracy Drift with Temperature Accuracy over Temperature Drift with Supply Threshold Voltage Trigger Voltage Trigger Current Reset Voltage Reset Current Threshold Current Control Voltage Level Pin 7 Leakage Output High Pin 7 Sat (Note 7) Output Low Output Low VCC = 15V, I7 = 15mA VCC = 4.5V, I7 = 4.5mA 180 80 200 mV mV (Note 6) VCC = 15V VCC = 5V 9 2.6 0.4 VCC = 15V VCC = 5V RA,RB = 1k to 100kΩ, C = 0.1µF, (Note 5) 3.0 0.30 0.667 5 1.67 0.5 0.5 0.1 0.1 10 3.33 1 0.9 1 0.4 0.25 11 4 100 % %/V x VCC V V µA V mA µA V nA 2.25 150 % ppm/˚C RA = 1k to 100kΩ, C = 0.1µF, (Note 5) 1.5 0.1 % %/V 1 50 % ppm/˚C



Electrical Characteristics (Notes 1, 2)

(Continued) (TA = 25˚C, VCC = +5V to +15V, unless othewise specified) ConditionsMin Limits LM555C Typ 0.1 0.4 2 2.5 Max 0.25 0.75 2.5 V V V V V 0.25 12.5 12.75 2.75 13.3 3.3 100 100 0.35 V V V V ns ns Units

Output Voltage Drop (Low)

VCC = 15V ISINK = 10mA ISINK = 50mA ISINK = 100mA ISINK = 200mA VCC = 5V ISINK = 8mA ISINK = 5mA

Output Voltage Drop (High)

ISOURCE = 200mA, VCC = 15V ISOURCE = 100mA, VCC = 15V VCC = 5V

Rise Time of Output Fall Time of Output...
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