SLVSAW6G June   2011  – April 2024 LP2951-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 ERROR Function
      2. 6.3.2 Programming Output Voltage
    4. 6.4 Device Functional Modes
      1. 6.4.1 Shutdown Mode
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
        1. 7.2.1.1 Input Capacitor (CIN)
        2. 7.2.1.2 Output Capacitor (COUT)
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Capacitance Value
        2. 7.2.2.2 Capacitor Types
        3. 7.2.2.3 CBYPASS: Noise and Stability Improvement
        4. 7.2.2.4 ESR Range
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

7.2.2.2 Capacitor Types

Most tantalum or aluminum electrolytics are acceptable for use at the input. Film-type capacitors also work but at higher cost. When operating at low temperature, care must be taken with aluminum electrolytics, because these electrolytes often freeze at –30°C. For this reason, use solid tantalum capacitors at temperatures below –25°C.

Ceramic capacitors can be used, but because of the low ESR (as low as 5 mΩ to 10 mΩ), these capacitors can possibly not meet the minimum ESR requirement previously discussed. If a ceramic capacitor is used, a series resistor between 0.1 Ω to 2 Ω must be added to meet the minimum ESR requirement. In addition, ceramic capacitors have one glaring disadvantage that must be taken into account — a poor temperature coefficient, where the capacitance can vary significantly with temperature. For instance, a large-value ceramic capacitor (≥ 2.2 μF) can lose more than half of the capacitance as temperature rises from 25°C to 85°C. Thus, a 2.2-μF capacitor at 25°C drops well below the minimum COUT required for stability as ambient temperature rises. For this reason, select an output capacitor that maintains the minimum 2.2 μF required for stability for the entire operating temperature range.