SLVSEL7B April   2019  – October 2019 TPS61390

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Circuit
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Recommended Operating Conditions
    2. 6.2 Absolute Maximum Ratings
    3. 6.3 ESD Ratings
    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 Undervoltage Lockout
      2. 7.3.2 Enable and Disable
      3. 7.3.3 Current Mirror
      4. 7.3.4 Sample and Hold
      5. 7.3.5 High Optical Power Protection
    4. 7.4 Device Functional Mode
      1. 7.4.1 PFM Operation
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirement
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1  Selecting the Rectifier Diode
        2. 8.2.2.2  Selecting the Inductor
        3. 8.2.2.3  Selecting Output Capacitor
        4. 8.2.2.4  Selecting Filter Resistor and Capacitor
        5. 8.2.2.5  Setting the Output Voltage
        6. 8.2.2.6  Selecting Sample Window
        7. 8.2.2.7  Selecting Capacitor for CAP pin
        8. 8.2.2.8  Selecting Capacitor for AVCC pin
        9. 8.2.2.9  Selecting Capacitor for APD pin
        10. 8.2.2.10 Selecting the Resistors of MON1 or MON2
        11. 8.2.2.11 Selecting the Capacitors of MON1 or MON2
        12. 8.2.2.12 Selecting the Resistor of Gain pin
        13. 8.2.2.13 Selecting the Short Current Limit
      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 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.2.2.2 Selecting the Inductor

It is suggested that the TPS61390 device works in the DCM operation; otherwise the output voltage would not be delivered for low input voltage to high output voltage.

With the device working in DCM operation, the maximum inductor could be calculated by equation Equation 3 and Equation 4:

Equation 3. TPS61390 eq_Lmax_SLVSEL7.gif

where

  • VIN is input voltage
  • D is duty cycle
  • fSW is switching frequency
  • ILIM is current limit

For instance, if VIN = 3.3 V, VOUT = 60 V, fSW = 600 kHz, ILIM = 0.8 A, the LMAX = 6.5 µH

However, there is minimum inductance is determined by the power delivered to the output side at given input condition.

Equation 4. TPS61390 eq_Lmin_SLVSEL7.gif

where

  • VOUT is output voltage
  • IOUT is output current
  • eff is the efficiency
  • fSW is switching frequency
  • ILIM is current limit

For instance, if IOUT = 8 mA, VOUT = 60 V, fSW = 600 kHz, ILIM = 0.8 A, eff = 0.6, the LMIN = 4.2 µH

With the calculation aforementioned, the operating inductor is recommended between the LMIN and LMAX.

The 4.7 µH inductance is optimum value for using the TPS61390 in application.