SE555 Datasheet PDF – Precision Timer – TI

What is SE555?

This is Precision Timer. It is a popular integrated circuit (IC) timer that is widely used in electronic circuits. It is also known as NE555, LM555, or simply 555 timer. The IC is a versatile timer that can be used to generate precise and stable time delays, oscillations, and pulse-width modulation signals.

Part Number: SE555

Function: Precision Timer

Package: PDIP, SOP, TSSOP, SOIC 8 Pin

Manufacturer: Texas Instruments

SE555 datasheet


These devices are precision timing circuits capable of producing accurate time delays or oscillation. In the time-delay or monostable mode of operation, the timed interval is controlled by a single external resistor and capacitor network. In the astable mode of operation, the frequency and duty cycle can be controlled independently with two external resistors and a single external capacitor.

The threshold and trigger levels normally are two-thirds and one-third, respectively, of Vcc. These levels can be altered by use of the control-voltage terminal. When the trigger input falls below the trigger level, the flip-flop is set, and the output goes high. If the trigger input is above the trigger level and the threshold input is above the threshold level, the flip-flop is reset and the output is low.

The reset (RESET) input can override all other inputs and can be used to initiate a new timing cycle. When RESET goes low, the flip-flop is reset, and the output goes low. When the output is low, a low-impedance path is provided between discharge (DISCH) and ground.

The output circuit is capable of sinking or sourcing current up to 200 mA. Operation is specified for supplies of 5 V to 15 V. With a 5-V supply, output levels are compatible with TTL inputs.

Block Diagram

SE555 Block diagram


1. Timing From Microseconds to Hours
2. Astable or Monostable Operation
3. Adjustable Duty Cycle
4. TTL-Compatible Output Can Sink or Source up to 200 mA

It has a number of useful features, including a wide operating voltage range (typically 4.5V to 18V), low power consumption, and high output current capability. It can be used in a variety of modes, as mentioned earlier, and can generate a range of output signals, including square waves, pulses, and ramps.


The SE555 timer is a simple and versatile IC that is widely available and inexpensive. Its ease of use, low cost, and wide range of applications make it a popular choice for both hobbyists and professionals. Additionally, the timer is capable of driving a wide range of loads, including LEDs, motors, and relays, making it useful in a variety of circuits.


While the timer has many advantages, it also has a few drawbacks. For example, it is not suitable for high-frequency applications due to its limited frequency range (typically up to a few hundred kilohertz). Additionally, the output of the timer can be affected by variations in temperature and supply voltage, which can lead to inaccuracies in timing.

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SE555 Datasheet PDF Download

SE555 pdf


Other data sheets are available within the file: NA555, NE555, SA555, NA555D, NA555DG4

LM555 Datasheet PDF | What is Timer IC?

What is LM555 Timer IC?

This is a popular integrated circuit chip used in a variety of electronic applications, primarily for timing and oscillator functions. It was first introduced by National Semiconductor (now part of Texas Instruments) in the 1970s.

Part Number: LM555

Function: Timer(Direct Replacement for SE555/NE555)

Package: SOIC, PDIP, VSSOP 8 Pin type

Manufacturer: Texas Instruments


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 a stable 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 200 mA or drive TTL circuits.


LM555 datasheet


Application Information ( LM555 Datasheet )

The LM555 timer can be used a various configurations, but the most commonly used configuration is in monostable mode. A typical application for the LM555 timer in monostable mode is to turn on an LED for a specific time duration. A pushbutton is used as the trigger to output a high pulse when trigger pin is pulsed low. This simple application can be modified to fit any application requirement.


1. Timing from Microseconds through Hours

2. Operates in Both Astable and Monostable Modes

3. Adjustable Duty Cycle

4. Output Can Source or Sink 200 mA

5. Output and Supply TTL Compatible



1. Timing and oscillator functions: Primarily used for timing and oscillator functions, such as generating clock signals, pulse-width modulation (PWM), and oscillation circuits.

2. Low power consumption: It is designed to operate with a low power consumption, making it suitable for use in battery-powered devices.

3. Wide operating voltage range: It has a wide operating voltage range of 4.5V to 16V, making it suitable for use in a variety of electronic devices.

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

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

Overall, LM555 is a versatile and widely used integrated circuit chip that offers a low-cost, low-power solution for timing and oscillator applications.


• Precision Timing

• Pulse Generation

• Sequential Timing

• Time Delay Generation

• Pulse Width Modulation

• Pulse Position Modulation

• Linear Ramp Generator


More Informations

555 Time ic Wiki Info, ne555 timer ic info

LM555 Datasheet

LM555 pdf

Other data sheets are available within the file:

555CM, 555CN, LM555CM, LM555CM-NOPB

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