ZHCSU10P March   2000  – February 2025 LP2981-N

PRODUCTION DATA  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  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 Diagrams
    3. 6.3 Feature Description
      1. 6.3.1 Output Enable
      2. 6.3.2 Dropout Voltage
      3. 6.3.3 Current Limit
        1. 6.3.3.1 Current Limit (Legacy Chip)
        2. 6.3.3.2 Current Limit (New Chip)
      4. 6.3.4 Undervoltage Lockout (UVLO)
      5. 6.3.5 Thermal Shutdown
      6. 6.3.6 Output Pulldown
    4. 6.4 Device Functional Modes
      1. 6.4.1 Normal Operation
      2. 6.4.2 Dropout Operation
      3. 6.4.3 Disabled
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Recommended Capacitor Types
        1. 7.1.1.1 Recommended Capacitors (Legacy Chip)
          1. 7.1.1.1.1 Tantalum Capacitors
          2. 7.1.1.1.2 Ceramic Capacitors
          3. 7.1.1.1.3 Aluminum Capacitors
        2. 7.1.1.2 Recommended Capacitors (New Chip)
      2. 7.1.2 Input and Output Capacitor Requirements
        1. 7.1.2.1 Input Capacitor
        2. 7.1.2.2 Output Capacitor
      3. 7.1.3 Estimating Junction Temperature
      4. 7.1.4 Power Dissipation (PD)
      5. 7.1.5 Reverse Current
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 ON and OFF Input Operation
      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 Device Nomenclature
    2. 8.2 第三方产品免责声明
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Related Documentation
    5. 8.5 支持资源
    6. 8.6 Trademarks
    7. 8.7 静电放电警告
    8. 8.8 术语表
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

7.2.2.1 ON and OFF Input Operation

The LP2981-N is shut off by pulling the ON/OFF input low, and turned on by driving the input high. If this feature is not to be used, the ON/OFF input is required to be tied to VIN to keep the regulator on at all times (the ON/OFF input must not be left floating).

For proper operation of the LDO, the signal source used to drive the ON/OFF input must be able to swing above and below the specified turnon/turnoff voltage thresholds which specify an ON or OFF state (see Electrical Characteristics).

The ON/OFF signal can come from either a totem-pole output, or an open-collector output with pullup resistor to the LP2981-N input voltage or another logic supply. The high-level voltage can exceed the LP2981-N input voltage, but must remain within the Absolute Maximum Ratings for the ON/OFF pin.

For the legacy chip only, the turnon and turnoff voltage signals applied to the ON/OFF input must have a slew rate greater than 40mV/μs.