SNAS548D February   2000  – January 2015 LM555

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Direct Replacement for SE555/NE555
      2. 7.3.2 Timing From Microseconds Through Hours
      3. 7.3.3 Operates in Both Astable and Monostable Mode
    4. 7.4 Device Functional Modes
      1. 7.4.1 Monostable Operation
      2. 7.4.2 Astable Operation
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Frequency Divider
        2. 8.2.2.2 Additional Information
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Trademarks
    2. 11.2 Electrostatic Discharge Caution
    3. 11.3 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

10 Layout

10.1 Layout Guidelines

Standard PCB rules apply to routing the LM555. The 0.1-µF capacitor in parallel with a 1-µF electrolytic capacitor should be as close as possible to the LM555. The capacitor used for the time delay should also be placed as close to the discharge pin. A ground plane on the bottom layer can be used to provide better noise immunity and signal integrity.

Figure 20 is the basic layout for various applications.

  • C1 – based on time delay calculations
  • C2 – 0.01-µF bypass capacitor for control voltage pin
  • C3 – 0.1-µF bypass ceramic capacitor
  • C4 – 1-µF electrolytic bypass capacitor
  • R1 – based on time delay calculations
  • U1 – LMC555

10.2 Layout Example

layoutex_snas548.gifFigure 20. Layout Example