ZHCSJX1B NOVEMBER   2008  – June 2019 TPS40197

PRODUCTION DATA.  

  1. 特性
  2. 应用
  3. 说明
    1.     Device Images
      1.      典型应用电路
  4. 修订历史记录
  5. 说明 (续)
  6. Pin Configuration and Functions
    1.     Pin Functions
  7. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Package Dissipation Ratings
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Enable
      2. 8.3.2  Oscillator
      3. 8.3.3  UVLO
      4. 8.3.4  Start-up Sequence and Timing
      5. 8.3.5  Selecting the Short Circuit Current
      6. 8.3.6  Voltage Reference and Dynamic VID
      7. 8.3.7  Minimum On-Time Consideration
      8. 8.3.8  BP Regulator
      9. 8.3.9  Prebias Start-up
      10. 8.3.10 Drivers
      11. 8.3.11 Power Good
      12. 8.3.12 Thermal Shutdown
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
  10. 10器件和文档支持
    1. 10.1 器件支持
      1. 10.1.1 第三方产品免责声明
    2. 10.2 文档支持
      1. 10.2.1 相关器件
      2. 10.2.2 相关文档
    3. 10.3 接收文档更新通知
    4. 10.4 社区资源
    5. 10.5 商标
    6. 10.6 静电放电警告
    7. 10.7 Glossary
  11. 11机械、封装和可订购信息

封装选项

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

Enable

The TPS40197 includes a dedicated EN pin. This simplifies user level interface design since no multiplexed functions exist. Another benefit is a true low-power shutdown mode of operation. When the EN pin is pulled to GND, all unnecessary functions, including the BP regulator, are turned off, reducing the IVDD current to 45 μA. A functionally equivalent circuit of the enable circuitry is shown in Figure 14.

TPS40197 v08097_lus853.gifFigure 14. Tps40197 En Pin Internal Circuitry

If the EN pin is left floating, the device starts automatically. The pin must be pulled to less than 600 mV to specify that the TPS40197 is in shutdown mode. Note that the EN pin is relatively high impedance. In some situations, there could be enough noise nearby to cause the EN pin to swing below the 600-mV threshold and give erroneous shutdown commands to other components of the device. There are two solutions to this potential problem.

  • Place a capacitor from EN to GND. A side-effect of this is to delay the start of the converter while the capacitor charges past the enable threshold.
  • Place a resistor from VDD to EN. This causes more current to flow in the shutdown mode, but does not delay converter start-up. If a resistor is used, the total current into the EN pin must be limited to no more than 500 μA.

The ENABLE pin is self clamping. The clamp voltage can be as low as 1 V with a 1-kΩ ground impedance. Due to this self-clamping feature, the pull-up impedance on the ENABLE pin should be selected to limit the sink current to less than 500 μA. Driving the ENABLE pin with a low-impedance source voltage can result in damage to the device. Because of the self-clamping feature, it requires care when connecting multiple ENABLE pins together. For enabling multiple TPS4019x devices (TPS40190, TPS40192, TPS40193, TPS40195, TPS40197), see application report SLVA509.