SLVSD88L July   2016  – August 2021 TPS61099

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and 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 Boost Controller Operation
      2. 8.3.2 Under-Voltage Lockout
      3. 8.3.3 Enable and Disable
      4. 8.3.4 Soft Start
      5. 8.3.5 Current Limit Operation
      6. 8.3.6 Output Short-to-Ground Protection
      7. 8.3.7 Over Voltage Protection
      8. 8.3.8 Down Mode Regulation and Pass-Through Operation
      9. 8.3.9 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Burst Mode Operation under Light Load Condition
      2. 8.4.2 Down Mode Regulation and Pass-Through Mode Operation
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application - 5 V Output Boost Converter
      1. 9.2.1 Design Requirements
        1. 9.2.1.1 Detailed Design Procedure
          1. 9.2.1.1.1 Custom Design With WEBENCH® Tools
          2. 9.2.1.1.2 Programming the Output Voltage
          3. 9.2.1.1.3 Maximum Output Current
          4. 9.2.1.1.4 Inductor Selection
          5. 9.2.1.1.5 Capacitor Selection
        2. 9.2.1.2 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
        1. 12.1.1.1 Custom Design With WEBENCH® Tools
      2. 12.1.2 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

Because the selection of the inductor affects steady state operation, transient behavior, and loop stability, the inductor is the most important component in power regulator design. There are three important inductor specifications, inductor value, saturation current, and dc resistance (DCR).

The TPS61099x is optimized to work with inductor values between 1 µH and 2.2 µH. For best stability consideration, a 2.2-µH inductor is recommended under Vout > 3.0V condition while choosing a 1-µH inductor for applications under Vout ≤ 3.0V condition. Follow Equation 3 and Equation 4 to calculate the inductor's peak current for the application. Depending on different load conditions, the TPS61099x works in continuous current mode or discontinuous mode. In different modes, the peak currents of the inductor are also different. Equation 3 provides an easy way to estimate whether the device works in CCM or DCM. As long as the Equation 3 is true, continuous current mode is typically established. Otherwise, discontinuous current mode is typically established.

Equation 3. GUID-19838A62-E49C-4D14-9036-B420FC3E95BF-low.gif

The inductor current ripple ILH is fixed by design. Therefore, the peak inductor current is calculated with Equation 4.

Equation 4. GUID-95CFBDC8-1A4F-4EC3-BE98-F18C04AD2008-low.gif

where

  • IL,peak is the peak inductor current.

The inductor's saturation current must be higher than the calculated peak inductor current. Table 9-2 lists the recommended inductors for TPS61099x device.

After choosing the inductor, the estimated switching frequency ƒ in continuous current mode can be calculated by Equation 5. The switching frequency is not a constant value, which is determined by L, VIN and VOUT.

Equation 5. GUID-D779F8A7-FF17-4714-B1FE-7DF15DA71D51-low.gif
Table 9-2 List of Inductors
VOUT [V](1)INDUCTANCE [µH]SATURATION CURRENT [A]DC RESISTANCE [mΩ]SIZE (LxWxH)PART NUMBERMANUFACTURER
> 3.02.21.95802.5 x 2.0 x 1.274404024022Würth Elektronik
2.21.7922.5 x 2.0 x 1.1LQH2HPN2R2MJRmuRata
2.21.451632.0 x 1.6 x 1.0VLS201610CX-2R2MTDK
≤ 3.01.02.6372.5 x 2.0 x 1.274404024010Würth Elektronik
1.02.3482.5 x 2.0 x 1.0MLP2520W1R0MT0S1TDK
1.01.5802.0 x 1.2 x 1.0LQM21PN1R0MGHmuRata
(1) See Third-Party Products disclaimer