ZHCSHU2B March   2018  – October 2018 TPS7A10

PRODUCTION DATA.  

  1. 特性
  2. 应用
  3. 说明
    1.     Device Images
      1.      压降与 IOUT 和温度间的关系(YKA 封装)
      2.      典型应用电路
  4. 修订历史记录
  5. Pin Configuration and Functions
    1.     Pin Functions
  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. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Excellent Transient Response
      2. 7.3.2 Global Undervoltage Lockout (UVLO)
      3. 7.3.3 Active Discharge
      4. 7.3.4 Enable
      5. 7.3.5 Sequencing Requirement
      6. 7.3.6 Internal Foldback Current Limit
      7. 7.3.7 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Mode
      2. 7.4.2 Dropout Mode
      3. 7.4.3 Disable Mode
  8. Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Recommended Capacitor Types
      2. 8.1.2 Input and Output Capacitor Requirements
      3. 8.1.3 Load Transient Response
      4. 8.1.4 Dropout Voltage
      5. 8.1.5 Behavior During Transition From Dropout Into Regulation
      6. 8.1.6 Undervoltage Lockout Circuit Operation
      7. 8.1.7 Power Dissipation (PD)
        1. 8.1.7.1 Estimating Junction Temperature
        2. 8.1.7.2 Recommended Area for Continuous Operation
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Input Current
        2. 8.2.2.2 Thermal Dissipation
      3. 8.2.3 Application Curve
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  11. 11器件和文档支持
    1. 11.1 器件支持
      1. 11.1.1 开发支持
        1. 11.1.1.1 评估模块
        2. 11.1.1.2 Spice 模型
      2. 11.1.2 器件命名规则
    2. 11.2 文档支持
      1. 11.2.1 相关文档
    3. 11.3 接收文档更新通知
    4. 11.4 社区资源
    5. 11.5 商标
    6. 11.6 静电放电警告
    7. 11.7 术语表
  12. 12机械、封装和可订购信息

Power Dissipation (PD)

Circuit reliability demands that proper consideration be given to device power dissipation, location of the circuit on the printed circuit board (PCB), and correct sizing of the thermal plane. The PCB area around the regulator must be as free as possible of other heat-generating devices that cause added thermal stresses.

Equation 2 calculates the maximum allowable power dissipation for the device in a given package:

Equation 2. PD-MAX = [(TJ – TA) / RθJA]

Equation 3 represents the actual power being dissipated in the device:

Equation 3. PD = (IGND+ IOUT) × (VIN – VOUT)

Power dissipation can be minimized, and thus greater efficiency achieved, by proper selection of the system voltage rails. Proper selection allows the minimum input-to-output voltage differential to be obtained. The low dropout of the TPS7A10 allows for maximum efficiency across a wide range of output voltages.

The main heat conduction path for the device depends on the ambient temperature and the thermal resistance across the various interfaces between the die junction and ambient air.

The maximum power dissipation determines the maximum allowable junction temperature (TJ) for the device. According to Equation 4, maximum power dissipation and junction temperature are most often related by the junction-to-ambient thermal resistance (RθJA) of the combined PCB and device package and the temperature of the ambient air (TA). The equation is rearranged in Equation 5 for output current.

Equation 4. TJ = TA + (RθJA × PD)
Equation 5. IOUT = (TJ – TA) / [RθJA × (VIN – VOUT)]

Unfortunately, this thermal resistance (RθJA) is highly dependent on the heat-spreading capability built into the particular PCB design, and therefore varies according to the total copper area, copper weight, and location of the planes. The RθJA recorded in the Thermal Information table is determined by the JEDEC standard, PCB, and copper-spreading area, and is only used as a relative measure of package thermal performance.