LM555 Datasheet PDF – Single Timer – Fairchild

The LM555 is widely used in various applications, such as pulse generation, timing circuits, frequency generation, delay circuits, and sequential timing. It finds applications in areas such as electronic instrumentation, control systems, robotics, and hobbyist projects.

Part Number: LM555

Function : Single Timer

Package: 8-DIP, 8-SOIC

Manufactuers : Fairchild




This LM555 Timer is a highly stable controller capable of producing accurate timing pulses. With a monostable operation, the delay is controlled by one external resistor and one capacitor.

With astable operation, the frequency and duty cycle are accurately controlled by two external resistors and one capacitor.

1. Timer and Oscillator: The IC can operate as either a monostable (one-shot) timer or an astable (free-running) oscillator. Its mode of operation can be selected by configuring external components.

2. Timing Control: The device allows for precise control over timing intervals. In monostable mode, it generates a single pulse of a duration determined by external resistors and capacitors. In astable mode, it generates a continuous train of square wave pulses with a frequency determined by external components.

3. Wide Range of Timing Intervals: The LM555 can provide timing intervals ranging from microseconds to hours, depending on the values of the external resistors and capacitors used.

4. Adjustable Duty Cycle: In astable mode, the 555 allows for adjustment of the duty cycle (the ratio of the pulse width to the period) by altering the values of the external resistors and capacitors.


1. High-Current Drive Capability: 200 mA
2. Adjustable Duty Cycle
3. Temperature Stability of 0.005%/°C
4. Timing From μs to Hours
5. Turn off Time Less Than 2 μs

Ordering Information

LM555 Ordering Information

LM555 Ordering Information


Application Information

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 high signal 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 transistor 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 signal is applied to the trigger voltage so that it becomes 1/3 of the supply voltage, the timer’s internal discharge transistor turns off, increasing the threshold voltage and driving the timer output again at high.


Block Diagram

LM555 Pinouts

LM555 Pinouts


• Precision Timing
• Pulse Generation
• Delay Generation
• Sequential Timing

Reference Homepage : LM555 Single Timer (onsemi.com)

LM555 Datasheet

LM555 pdf datasheet

Related Partnumber : LM555CM, LM555CMX, LM555CN


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What is 1N5819? – 1A, 40V, Diode, Schottky Barrier Rectifier

What is 1N5819?

This is a Schottky diode that is commonly used in electronic circuits. It has a low forward voltage drop and a fast switching speed, making it useful for applications such as voltage regulation, rectification, and power supply protection. The diode is rated for a maximum voltage of 40V and a maximum current of 1A.

Function : 40V, 1.0 Ampere Schottky Barrier Rectifier, Diode

Package: DO-41 type

Manufacturer: Fairchild Semiconductor



Advantages Vs Disadvantages


1. Low forward voltage drop reduces power dissipation and improves efficiency in voltage regulation and rectification circuits.
2. Fast switching speed makes it useful in applications that require rapid switching, such as power supply protection circuits.
3. High surge current capability allows the diode to handle short-term overloads without damage.
4. Low reverse leakage current minimizes power losses and improves circuit performance.


1. Low maximum rated voltage and current limit the diode’s usefulness in high-power applications.
2. The low forward voltage drop can cause the diode to conduct even with low forward bias voltages, which can be a problem in some circuits.
3. The high switching speed can cause ringing and other unwanted effects in some circuits, which may require additional circuit design measures to mitigate.


This is Schottky Barrier Rectifier.

1. 1.0 ampere operation at TA = 90°C with no thermal runaway.
2. For use in low voltage, high frequency inverters free wheeling, and polarity protection applications.

Absolute Maximum Ratings and Characteristics


Absolute Maximum Ratings (Ta = 25°C)

1. Maximum Repetitive Reverse Voltage: Vrrm = 40V

2. Average Rectified Forward Current: IF(AV) = 1A

3. Power Dissipation : 1.25 W

5. Operating Junction: Tj = -65 to +150 °C

6. Storage temperature: Tstg = -65 to +150 °C


1N5819 Datasheet

1N5819 pdf



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