SNVA432D March   2010  – January 2022 LM21305

 

  1.   Trademarks
  2. 1 LM21305 Overview
  3. 2 Typical Application Circuit
  4. 3 Evaluation Board Schematic
  5. 4 Evaluation Board Bill of Materials (BOM)
  6. 5 Connection Descriptions
  7. 6 Jumper Settings
  8. 7 Other Design Examples
  9. 8 Typical Performance Characteristics
  10. 9 Component Selection
    1. 9.1 Input Capacitors
    2. 9.2 AVIN Filter
    3. 9.3 Switching Frequency Selection
    4. 9.4 Inductor
    5. 9.5 Output Capacitor
    6. 9.6 Compensation Circuit
  11. 10PCB Layout
  12. 11Revision History

7 Other Design Examples

The LM21305 is designed to fit a wide variety of applications. A design calculator tool for the LM21305 is available to accelerate the design process. Also, the LM21305 is enabled through Texas Instruments WEBENCH® power designer. A few design examples are given here for convenience and only the components that need to be modified are listed below. Design examples are for the following:

  • PVIN = 12 V
  • fs = 500 kHz
  • IOUT-MAX = 5 A
  • VOUT = 1.2V, 1.8 V, 2.5 V, 3.3 V, and 5 V
VOUT 1.2 V 1.8 V 2.5 V 3.3 V 5 V
C6 3300 pF, 25 V 3300 pF, 25 V 4700 pF, 25 V 4700 pF, 25 V 4700 pF, 25 V
L1 1.5 µH, 10 A 2.2 µH, 10 A 2.2 µH, 10 A 3.3 µH, 10 A 3.3 µH, 10 A
R5 10 kΩ, 1% 20 kΩ, 1% 31.6 kΩ, 1% 45.3 kΩ, 1% 73.2 kΩ, 1%
R7 3.32 kΩ, 1% 4.22 kΩ, 1% 5.10 kΩ, 1% 7.15 kΩ, 1% 8.2 kΩ, 1%