ZHCSJW0D June   2019  – March 2020 TPS62840

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      典型应用
      2.      效率与负载电流间的关系 (VOUT = 1.8V)
  4. 4 修订历史记录
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 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 Smart Enable and Shutdown
      2. 8.3.2 Soft Start
      3. 8.3.3 Mode Selection: Power-Save Mode (PFM/PWM) or Forced PWM Operation (FPWM)
      4. 8.3.4 Output Voltage Selection (VSET)
      5. 8.3.5 Undervoltage Lockout UVLO
      6. 8.3.6 Switch Current Limit / Short Circuit Protection
      7. 8.3.7 Output Voltage Discharge
      8. 8.3.8 Thermal Shutdown
      9. 8.3.9 STOP Mode
    4. 8.4 Device Functional Modes
      1. 8.4.1 Power-Save Mode Operation
      2. 8.4.2 Forced PWM Mode Operation
      3. 8.4.3 100% Mode Operation
  9. 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
        1. 9.2.2.1 Inductor Selection
        2. 9.2.2.2 Output Capacitor Selection
        3. 9.2.2.3 Input Capacitor Selection
      3. 9.2.3 Application Curves
    3. 9.3 System Example
  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 器件支持
      1. 12.1.1 第三方产品免责声明
    2. 12.2 保障资源
    3. 12.3 商标
    4. 12.4 静电放电警告
    5. 12.5 Glossary
  13. 13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

9.2.2.1 Inductor Selection

The inductor value affects the peak-to-peak ripple current, PWM-to-PFM transition point, output voltage ripple, and efficiency. The selected inductor has to be rated for its DC resistance and saturation current. The inductor ripple current (ΔIL) decreases with higher inductance and increases with higher VIN or VOUT and can be estimated according to Equation 4.

Equation 5 calculates the maximum inductor current under static load conditions. The saturation current of the inductor must be rated higher than the maximum inductor current, as calculated with Equation 5. This is recommended because during a heavy load transient the inductor current rises above the calculated value. A more conservative way is to select the inductor saturation current according to the high-side MOSFET switch current limit, ILIMF.

Equation 4. TPS62840 eq4_dil_lvs941.gif
Equation 5. TPS62840 eq5_ilmax_lvs941.gif

where

  • f is the switching frequency
  • L is the inductance
  • ΔIL is the peak-to-peak inductor ripple current
  • ILmax is the maximum inductor current

Table 4 shows a list of possible inductors.

Table 4. List of Possible Inductors(1)

INDUCTANCE [µH] INDUCTOR TYPE SIZE [L x W x T] SUPPLIER
2.2 DFE201612E [2.0 mm x 1.6 mm x 1.2 mm max.] muRata
2.2 DFE201210S [2.0 mm x 1.2 mm x 1.0 mm max.] muRata