LM555 Timer - Datasheet

Nov 1, 2026

Uploaded by Aria

LM555 Timer datasheet covering a highly stable IC for generating accurate time delays and oscillation. Describes operation in time-delay, astable, and monostable modes, including controllable frequency, duty cycle, triggering/reset behavior, and TTL-compatible output drive up to 200 mA. Provides key features and applications such as precision timing, pulse generation, modulation, and linear ramp generation, plus schematic/connection information. Includes ordering details, absolute maximum ratings, soldering guidance, and electrical characteristics with test conditions and parameter limits.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages17

Reading Time43 min

AccessFree to download

LM555 Timer

General Description

Features

Applications

Schematic Diagram

Connection Diagram

Ordering Information

Absolute Maximum Ratings

Soldering Information

Electrical Characteristics

National Semiconductor is now part of Texas Instruments . Search [http://www.ti.com/](http://www.ti.com/ for)[ for](http://www.ti.com/ for) the latest technical information and details on our current products and services . | | | February 2000 | | --- | --- | --- | | 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 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. | Features
n Direct replacement for SE555/NE555
n Timing from microseconds through hours n Operates in both astable and monostable modes n Adjustable duty cycle
n Output can source or sink 200 mA
n Output and supply TTL compatible n Temperature stability better than 0 .005% per ˚Cn Normally on and normally off output n Available in 8-pin MSOP package
Applications
n Precision timing n Pulse generation n Sequential timing
n Time delay generation n Pulse width modulation
n Pulse position modulation
n Linear ramp generator | | | Schematic Diagram | | | | | | | | DS007851-1 | | | © 2000 National Semiconductor Corporation DS007851 [www.national.com](www.national.com) LM555 Timer LM555 Connection Diagram Dual-In-Line, Small Outline and Molded Mini Small Outline Packages DS007851-3 Top View Ordering Information | Package | Part Number | Package Marking | Media Transport | NSC Drawing | | --- | --- | --- | --- | --- | | 8-Pin SOIC | LM555CM | LM555CM | Rails | M08A | | | LM555CMX | LM555CM | 2.5k Units Tape and Reel | | | 8-Pin MSOP | LM555CMM | Z55 | 1k Units Tape and Reel | MUA08A | | | LM555CMMX | Z55 | 3.5k Units Tape and Reel | | | 8-Pin MDIP | LM555CN | LM555CN | Rails | N08E | [www.national.com](www.national.com) 2 | 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 +18V
Power Dissipation (Note 3)
LM555CM, LM555CN 1180 mW
LM555CMM 613 mW
Operating Temperature Ranges
LM555C 0˚C to +70˚C
Storage Temperature Range −65˚C to +150˚C | | Soldering Information Dual-In-Line Package
Soldering (10 Seconds) 260˚C
Small Outline Packages (SOIC and MSOP)
Vapor Phase (60 Seconds) 215˚C
Infrared (15 Seconds) 220˚C See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” for other methods of soldering surface mount devices. | | | | | | --- | --- | --- | --- | --- | --- | --- | | Electrical Characteristics (Notes 1, 2)
(TA = 25˚C, VCC = +5V to +15V, unless othewise specified) | | | | | | | | Parameter | Conditions | | Limits | | | Units | | | | | LM555C | | | | | | | | Min | Typ | Max | | | Supply Voltage | | | 4.5 | | 16 | V | | Supply Current | VCC = 5V, RL = ∞
VCC = 15V, RL = ∞
(Low State) (Note 4) | | | 3
10 | 6
15 | mA | | Timing Error, Monostable Initial Accuracy
Drift with Temperature
Accuracy over Temperature Drift with Supply | RA = 1k to 100kΩ ,
C = 0.1µF,(Note 5) | | | 1
50
1.5
0.1 | | %
ppm/˚C
%
%/V | | Timing Error, Astable Initial Accuracy
Drift with Temperature
Accuracy over Temperature Drift with Supply | RA, RB = 1k to 100kΩ ,
C = 0.1µF,(Note 5) | | | 2.25
150
3.0
0.30 | | %
ppm/˚C
%
%/V | | Threshold Voltage | | | | 0.667 | | x VCC | | Trigger Voltage | VCC = 15V
VCC = 5V | | | 5
1.67 | | V
V | | Trigger Current | | | | 0.5 | 0.9 | µA | | Reset Voltage | | | 0.4 | 0.5 | 1 | V |

FAQs

What are the primary functions of the LM555 timer?

The LM555 provides accurate time delays and oscillation. It operates in time-delay (monostable) and astable oscillator modes to generate stable timing and waveforms.

How can frequency and duty cycle be controlled in astable operation?

In astable mode, the free-running frequency and duty cycle are controlled by two external resistors and one capacitor.

What output current can the LM555 source or sink?

The output circuit can source or sink up to 200 mA, with the output and supply designed to be TTL compatible.

Nov 1, 2026

Uploaded by Aria