ZHCSC50B February   2014  – September 2014 TPS22961

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用范围
  3. 3 说明
  4. 4 简化电路原理图
  5. 5 修订历史记录
  6. 6 Terminal Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 Handling Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics, VBIAS = 5.0 V
    6. 7.6 Electrical Characteristics, VBIAS = 3.0 V
    7. 7.7 Switching Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 On/off Control
      2. 8.3.2 Input Capacitor (CIN)
      3. 8.3.3 Output Capacitor (CL)
      4. 8.3.4 VIN and VBIAS Voltage Range
  9. 9 Applications and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Typical Application Powering a Downstream Module
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 VIN to VOUT Voltage Drop
          2. 9.2.1.2.2 Inrush Current
          3. 9.2.1.2.3 Thermal Considerations
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Typical Application Powering Rails Sensitive to Ringing and Overvoltage due to Fast Rise Time
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
          1. 9.2.2.2.1 Picking Proper Inductor and Capacitor to Meet Voltage Overshoot Requirements
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12器件和文档支持
    1. 12.1 商标
    2. 12.2 静电放电警告
    3. 12.3 术语表
  13. 13机械封装和可订购信息

封装选项

请参考 PDF 数据表获取器件具体的封装图。

机械数据 (封装 | 引脚)
  • DNY|8
散热焊盘机械数据 (封装 | 引脚)
订购信息

8 Detailed Description

8.1 Overview

The device is a 3.5 V, 6 A load switch in a 8-terminal SON package. To reduce voltage drop for low voltage and high current rails, the device implements an ultra-low resistance N-channel MOSFET which reduces the drop out voltage through the device at very high currents.

The device has a controlled, yet quick, fixed slew rate for applications that require quick turn-on response. During shutdown, the device has very low leakage currents, thereby reducing unnecessary leakages for downstream modules during standby. Integrated control logic, driver, and output discharge FET eliminates the need for any external components, which reduces solution size and BOM count.

8.2 Functional Block Diagram

TPS22961 fbd_slvsci4.gif

8.3 Feature Description

8.3.1 On/off Control

The ON terminal controls the state of the load switch, and asserting the terminal high (active high) enables the switch. The ON terminal is compatible with standard GPIO logic threshold and can be used with any microcontroller or discrete logic with 1.2 V or higher GPIO voltage. This terminal cannot be left floating and must be tied either high or low for proper functionality.

8.3.2 Input Capacitor (CIN)

To limit the voltage drop on the input supply caused by transient in-rush currents when the switch turns on into a discharged load capacitor or short-circuit, a capacitor needs to be placed between VIN and GND. A 1 µF ceramic capacitor, CIN, placed close to the terminals, is usually sufficient. Higher values of CIN can be used to further reduce the voltage drop in high-current application. When switching heavy loads, it is recommended to have an input capacitor 10 times higher than the output capacitor to avoid excessive voltage drop.

8.3.3 Output Capacitor (CL)

Due to the integrated body diode in the NMOS switch, a CIN greater than CL is highly recommended. A CL greater than CIN can cause VOUT to exceed VIN when the system supply is removed. This could result in current flow through the body diode from VOUTT to VIN. A CIN to CL ratio of 10 to 1 is recommended for minimizing VIN dip caused by inrush currents during startup, however a 10 to 1 ratio for capacitance is not required for proper functionality of the device. A ratio smaller than 10 to 1 (such as 1 to 1) could cause a VIN dip upon turn-on due to inrush currents.

8.3.4 VIN and VBIAS Voltage Range

For optimal RON performance, make sure VIN ≤ (VBIAS – 1.95 V). For example, in order to have VIN = 3.5V, VBIAS must be 5.5 V. The device will still be functional if VIN > (VBIAS – 1.95 V) but it will exhibit RON greater than what is listed in the Electrical Characteristics, VBIAS = 5.0 V table. See Figure 25 for an example of a typical device. Notice the increasing RON as VIN increases. Be sure to never exceed the maximum voltage rating for VIN and VBIAS.

TPS22961 C023_slvsci7.png Figure 25. RON vs VIN (VIN > VBIAS)