SLUSEQ8A november   2021  – may 2023 TPS62441 , TPS62442

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 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 Timing Requirements
    7. 7.7 Typical Characteristics
  9. 8 Parameter Measurement Information
    1. 8.1 Schematic
  10. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Precise Enable (EN)
      2. 9.3.2 COMP/FSET
      3. 9.3.3 MODE/SYNC
      4. 9.3.4 Undervoltage Lockout (UVLO)
      5. 9.3.5 Power-Good Output (PG)
      6. 9.3.6 Thermal Shutdown
    4. 9.4 Device Functional Modes
      1. 9.4.1 Pulse Width Modulation (PWM) Operation
      2. 9.4.2 Power Save Mode Operation (PWM/PFM)
      3. 9.4.3 100% Duty-Cycle Operation
      4. 9.4.4 Current Limit and Short-Circuit Protection
      5. 9.4.5 Output Discharge
      6. 9.4.6 Soft Start
  11. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Programming the Output Voltage
      2. 10.1.2 External Component Selection
        1. 10.1.2.1 Inductor Selection
        2. 10.1.2.2 Capacitor Selection
          1. 10.1.2.2.1 Input Capacitor
          2. 10.1.2.2.2 Output Capacitor
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curves
    3. 10.3 Power Supply Recommendations
    4. 10.4 Layout
      1. 10.4.1 Layout Guidelines
      2. 10.4.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

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

10.1.2.1 Inductor Selection

The TPS6244x is designed for a nominal 0.47-µH inductor with a switching frequency of typically 2.25 MHz. Larger values can be used to achieve a lower inductor current ripple but they can have a negative impact on efficiency and transient response. Smaller values than 0.47 µH cause a larger inductor current ripple, which causes larger negative inductor current in forced PWM mode at low or no output current. For a higher or lower nominal switching frequency, the inductance must be changed accordingly.

The inductor selection is affected by several effects like the following:

  • Inductor ripple current
  • Output ripple voltage
  • PWM-to-PFM transition point
  • Efficiency

In addition, the inductor selected has to be rated for appropriate saturation current and DC resistance (DCR). THe following equation calculates the maximum inductor current.

Equation 7. I L m a x = I O U T ( m a x ) + Δ I L ( m a x ) 2
Equation 8. Δ I L m a x = V O U T × 1 - V O U T V I N L m i n × 1 f s w

where

  • IL(max) is the maximum inductor current.
  • ΔIL(max) is the peak-to-peak inductor ripple current.
  • Lmin is the minimum inductance at the operating point.

Table 10-1 Typical Inductors
TYPE INDUCTANCE [µH] CURRENT [A](1) FOR DEVICE NOMINAL SWITCHING FREQUENCY DIMENSIONS [L × B × H] mm MANUFACTURER(2)
DFE201210U-R47M 0.47 µH, ±20% see data sheet TPS62442 2.25 MHz 2.0× 1.2 × 1.0 Murata
DFE201210U-R68M 0.68 µH, ±20% see data sheet TPS62441 2.25 MHz 2.0 × 1.2 × 1.0 Murata
DFE201610E-R47M# 0.47 µH, ±20% see data sheet TPS62442 2.25 MHz 2.0 × 1.6 × 1.0 Murata
XEL3515-561ME 0.56 µH, ±20% 4.5 TPS62442 2.25 MHz 3.5 × 3.2 × 1.5 Coilcraft
XFL4015-701ME 0.70 µH, ±20% 5.3 TPS62442 2.25 MHz 4.0 × 4.0 × 1.6 Coilcraft
XFL4015-471ME 0.47 µH, ±20% 5.4 TPS62442 2.25 MHz 4.0 × 4.0 × 1.6 Coilcraft
TFM201610ALM-R47MTAA 0.47 µH, ±20% 5.8 TPS62442 2.25 MHz 2.0 × 1.6 × 1.0 TDK
(1) Lower of IRMS at 20°C rise or ISAT at 20% drop.

Calculating the maximum inductor current using the actual operating conditions gives the minimum saturation current of the inductor needed. TI recommends to add a margin of about 20%. A larger inductor value is also useful to get lower ripple current, but increases the transient response time and size as well.