LM555 Timer IC – Circuit, LM555CN Datasheet – National

Part Number: LM555

Manufacturer: National Semiconductor

Package: 8-pin MSOP

Function: Highly stable device for generating accurate time delays or oscillation

ImageLM555 datasheet national


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 running frequency 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.

Timer IC LM555 Pinout

Timer IC LM555 Pinout


1. Direct replacement for SE555/NE555
2. Timing from microseconds through hours
3. Operates in both astable and monostable modes
4. Adjustable duty cycle
5. Output can source or sink 200 mA
6. Output and supply TTL compatible
7. Temperature stability better than 0.005% per ˚C
8. Normally on and normally off output


LM555 Schematic Diagram

LM555 Shematic Diagram



1. Single timer: Single timer integrated circuit chip that contains a voltage comparator, a flip-flop, and a discharge transistor.

2. Output: It can provide either a digital output (0 or 1) or an analog output, depending on the application.

3. Frequency range: It can operate at frequencies ranging from a few hertz to several megahertz, depending on the external components used.

Ordering Information

LM555 Ordering Information


Datasheet Download : [ LM555 Timer IC.PDF ]

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