JAJSSB2 September   2024 TPS548B23

ADVANCE INFORMATION  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 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
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  D-CAP4 Control
      2. 7.3.2  Internal VCC LDO and Using External Bias On the VCC Pin
        1. 7.3.2.1 Powering the Device From a Single Bus
        2. 7.3.2.2 Powering the Device From a Split-Rail Configuration
      3. 7.3.3  Multifunction Configuration (CFG1-5) Pins
        1. 7.3.3.1 Multifunction Configuration (CFG1-2) Pins (Internal Feedback)
        2. 7.3.3.2 Multifunction Configuration (CFG1-2) Pins (External Feedback)
        3. 7.3.3.3 Multifunction Configuration (CFG3-5) Pins
      4. 7.3.4  Enable
      5. 7.3.5  Soft Start
      6. 7.3.6  Power Good
      7. 7.3.7  Overvoltage and Undervoltage Protection
      8. 7.3.8  Remote Sense
      9. 7.3.9  Low-side MOSFET Zero-Crossing
      10. 7.3.10 Current Sense and Positive Overcurrent Protection
      11. 7.3.11 Low-side MOSFET Negative Current Limit
      12. 7.3.12 Output Voltage Discharge
      13. 7.3.13 UVLO Protection
      14. 7.3.14 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Auto-Skip (PFM) Eco-mode Light Load Operation
      2. 7.4.2 Forced Continuous-Conduction Mode
  9. 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 Output Voltage Setting Point
        2. 8.2.2.2 Choose the Switching Frequency
        3. 8.2.2.3 Choose the Inductor
        4. 8.2.2.4 Choose the Output Capacitor
        5. 8.2.2.5 Choose the Input Capacitors (CIN)
        6. 8.2.2.6 VCC Bypass Capacitor
        7. 8.2.2.7 BOOT Capacitor
        8. 8.2.2.8 PG Pullup Resistor
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 ドキュメントの更新通知を受け取る方法
    3. 9.3 サポート・リソース
    4. 9.4 Trademarks
    5. 9.5 静電気放電に関する注意事項
    6. 9.6 用語集
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
  • VAN|19
サーマルパッド・メカニカル・データ
発注情報

7.3.4 Enable

When the EN pin voltage rises above the enable threshold voltage (VEN(R)) and VIN rises above the VIN UVLO rising threshold, the device enters the internal power-up sequence.

The EN pin has an internal filter to avoid unexpected ON or OFF due to small glitches. The time constant of this RC filter is 2µs. For example, when applying 3.3V voltage source on the EN pin that jumps from 0V to 3.3V with an ideal rising edge, the internal EN signal will reach 2.1V after 2µs, which is 63.2% of applied 3.3V voltage level.

An internal pulldown resistor is implemented between the EN pin and AGND pin. With this pulldown resistor, floating the EN pin before start-up keeps the device in the disabled state. A resistor divider to the EN pin can be used to increase the input voltage the device begins the start-up sequence. The internal pulldown resistor must be accounted for when using an external resistor divider. To reduce impact to the EN rising and falling threshold, this internal pulldown resistor is 1MΩ. During nominal operation when the power stage switches, this large internal pulldown resistor can not have enough noise immunity to hold EN pin low for the device to enter the disabled state.

If an external resistor divider is connected to the EN pin, an additional 5µA current source is activated when the EN voltage exceeds the rising threshold to provide a programmable hysteresis based on the enable falling threshold voltage (VEN(F)) and external resistors.

The recommended operating condition for the EN pin is a maximum of 5.5V. Do not connect the EN pin to the VIN pin directly if VIN can exceed 5.5V.