JAJSJP3A September   2020  – October 2020 TPS51397A

PRODUCTION DATA  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
  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 PWM Operation and DCAP3 Control
      2. 7.3.2 Soft Start
      3. 7.3.3 Large Duty Operation
      4. 7.3.4 Power Good
      5. 7.3.5 Overcurrent Protection and Undervoltage Protection
      6. 7.3.6 Overvoltage Protection
      7. 7.3.7 UVLO Protection
      8. 7.3.8 Output Voltage Discharge
      9. 7.3.9 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Light Load Operation
      2. 7.4.2 Advanced Eco-mode Control
      3. 7.4.3 Out-of-Audio
      4. 7.4.4 Mode Selection
      5. 7.4.5 Standby 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 External Component Selection
          1. 8.2.2.1.1 Output Voltage Set Point
          2. 8.2.2.1.2 MODE Selection
          3. 8.2.2.1.3 Inductor Selection
          4. 8.2.2.1.4 Output Capacitor Selection
          5. 8.2.2.1.5 Input Capacitor Selection
      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 Receiving Notification of Documentation Updates
    2. 11.2 サポート・リソース
    3. 11.3 Trademarks
    4. 11.4 静電気放電に関する注意事項
    5. 11.5 用語集
  12. 12Mechanical, 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）
サーマルパッド・メカニカル・データ
発注情報

5 Pin Configuration and Functions

GUID-20200825-CA0I-SHXZ-4JQ3-JPJN0DNZMWND-low.gif Figure 5-1 20-Pin VQFN RJE Package (Top View)
Table 5-1 Pin Functions
PIN I/O DESCRIPTION
NAME NO.
BST 1

O

 Supply input for the gate drive voltage of the high-side MOSFET. Connect the bootstrap capacitor between BST and SW. 0.1 μF is recommended.
VIN 2,3,4,5 P Input voltage supply pin for the control circuitry. Connect the input decoupling capacitors between VIN and PGND.
SW 6,19,20 O Switching node connection to the inductor and bootstrap capacitor for buck. This pin voltage swings from a diode voltage below the ground up to input voltage of buck.
PGND 7,8,18, Thermal Pad G Power GND terminal for the controller circuit and the internal circuitry
PGOOD 9 O Open-drain power-good indicator. It is asserted low if output voltage is out of PG threshold, over voltage, or if the device is under thermal shutdown, EN shutdown, or during soft start.
SS 11

O

 Soft-Start time selection pin. Connecting an external capacitor sets the soft-start time and if no external capacitor is connected, the soft-start time is about 1.2 ms.
NC 10,16 Not connect. Can be connected to GND plane for better thermal achieved.
EN 12 I Enable input of buck converter
AGND 13 G Ground of internal analog circuitry. Connect AGND to GND plane with a short trace.
FB 14 I Feedback sensing pin for Buck output voltage. Connect this pin to the resistor divider between output voltage and AGND.
MODE 15 I Switching frequency and light load operation mode selection pin. Connect this pin to a resistor divider from VCC and AGND for different MODE options shown in Table 7-1.
VCC 17 O The driver and control circuits are powered from this voltage. Decouple with a minimum 1-μF ceramic capacitor as close to VCC as possible.