SLVSEX0A March   2019  – July 2019 TLV61048

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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. 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 Soft Start
      4. 7.3.4 Frequency Select (FREQ)
    4. 7.4 Device Functional Modes
      1. 7.4.1 PWM Mode
      2. 7.4.2 PFM Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 12-V Output Boost Converter With External Bias
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Programming the Output Voltage
          2. 8.2.1.2.2 Inductor Selection
          3. 8.2.1.2.3 Input and Output Capacitor Selection
          4. 8.2.1.2.4 Diode Rectifier Selection
        3. 8.2.1.3 Application Curves
      2. 8.2.2 14-V Output Boost Converter
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1 Inductor Selection
          2. 8.2.2.2.2 Input and Output Capacitor Selection
  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 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.1.2.2 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 TLV61048 is designed to work with inductor values between 2.2 µH and 10 µH. Use Equation 2 to Equation 4 to calculate the peak current of the application inductor. To calculate the current in the worst case, use the minimum input voltage, maximum output voltage, and maximum load current of the application. To have enough design margin, choose the inductor value with –30% tolerance, and a low power-conversion efficiency for the calculation. In a boost regulator, the inductor dc current can be calculated with Equation 2.

Equation 2. TLV61048 EQ2_slvscq7.gif

where

  • VOUT = output voltage
  • IOUT = output current
  • VIN = input voltage
  • η = power conversion efficiency, use 80% for most applications

The inductor ripple current is calculated with the Equation 3 for an asynchronous boost converter in continuous conduction mode (CCM).

Equation 3. TLV61048 EQ3_slvscq7.gif

where

  • ΔIL(P-P) = inductor ripple current
  • L = inductor value
  • fSW = switching frequency
  • VOUT = output voltage
  • VIN = input voltage

Therefore, the inductor peak current is calculated with Equation 4.

Equation 4. TLV61048 EQ4_slvscq7.gif

Normally, it is advisable to work with an inductor peak-to-peak current of less than 40% of the average inductor current for maximum output current. A smaller ripple from a larger valued inductor reduces the magnetic hysteresis losses in the inductor and EMI. However, in the same way, load transient response time is increased. Table 2 lists the recommended inductor for the TLV61048 in the 600-kHz configuration.

Table 2. Recommended Inductors for the TLV61048 at 600-kHz Configuration

PART NUMBER L (µH) DCR MAX (mΩ) SATURATION CURRENT TYPICAL (A) SIZE (L×W×H) (mm) VENDOR(1)
SWPA5040S4R7NT 4.7 39 3.9 5 × 5 × 4 Sunlord
XAL4030-472ME 4.7 44.1 4.5 4 × 4 × 3 Coilcraft
SWPA5040S100MT 10 83 2.9 5 × 5 × 4 Sunlord
XAL4040-103ME 10 92.4 3 4 × 4 × 4 Coilcraft