SNVS874E August   2012  – September 2021 LMZ20501

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 System Characteristics
    7. 6.7 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 Nano Scale Package
      2. 7.3.2 Internal Synchronous Rectifier
      3. 7.3.3 Current Limit Protection
      4. 7.3.4 Start-Up
      5. 7.3.5 Dropout Behavior
      6. 7.3.6 Power Good Flag Function
      7. 7.3.7 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 PWM Operation
      2. 7.4.2 PFM Operation
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Detailed Design Procedure
        1. 8.2.1.1 Custom Design With WEBENCH® Tools
        2. 8.2.1.2 Setting The Output Voltage
        3. 8.2.1.3 Output and Feedforward Capacitors
        4. 8.2.1.4 Input Capacitors
        5. 8.2.1.5 Maximum Ambient Temperature
        6. 8.2.1.6 Options
      2. 8.2.2 Application Curves
    3. 8.3 Do's and Don'ts
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
      1. 10.2.1 Soldering Information
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
      2. 11.1.2 Development Support
        1. 11.1.2.1 Custom Design With WEBENCH® Tools
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Tape and Reel Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • SIL|8
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.2.1.4 Input Capacitors

The ceramic input capacitors provide a low impedance source to the regulator in addition to supplying ripple current and isolating switching noise from other circuits. An effective value of at least 14 µF is normally sufficient for the input capacitor. If the main input capacitor or capacitors cannot be placed close to the module, then a small 10 nF to 100 nF capacitor should be placed directly at the module across the supply and ground pins.

Many times, it is desirable to use an electrolytic capacitor on the input, in parallel with the ceramics. This is especially true if long leads/traces are used to connect the input supply to the regulator. The moderate ESR of this capacitor can help damp any ringing on the input supply caused by long power leads. This method can also help to reduce voltage spikes that can exceed the maximum input voltage rating of the LMZ20501. The use of this additional capacitor will also help with voltage dips caused by input supplies with unusually high impedance.

Most of the switching current passes through the input ceramic capacitor or capacitors. The approximate RMS value of this current can be calculated with Equation 2 and should be checked against the manufactures maximum ratings.

Equation 2. GUID-A99F8C93-1230-44DE-8A4C-3105BDDBD314-low.gif