SNVS457D February   2007  – October 2015 LM26400Y

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Overcurrent Protection
      2. 7.3.2 Loop Stability
      3. 7.3.3 Load Step Response
    4. 7.4 Device Functional Modes
      1. 7.4.1 Start-Up and Shutdown
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 LM26400Y Design Example 1
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 LM26400Y Design Example 2
  9. 9 Power Supply Recommendations
    1. 9.1 Low Input Voltage Considerations
    2. 9.2 Programming Output Voltage
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Thermal Shutdown
      2. 10.1.2 Power Loss Estimation
      3. 10.1.3 Inductor Selection
      4. 10.1.4 Output Capacitor Selection
      5. 10.1.5 Input Capacitor Selection
      6. 10.1.6 Catch Diode Selection
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    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

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8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LM26400Y device will operate with input voltage from 3 V to 20 V and provide two regulated output voltages. The device is optimized for high-efficiency operation with minimum number of external components.

8.2 Typical Applications

8.2.1 LM26400Y Design Example 1

LM26400Y 20200253.png

8.2.1.1 Design Requirements

The device must be able to operate at any voltage within the recommended operating range. The load current must be defined in order to properly size the inductor, input, and output capacitors .The inductor must be able to handle full expected load current as well as the peak current generated load transients and start-up.

8.2.1.2 Detailed Design Procedure

The best capacitors for use with the LM26400Y are multi-layer ceramic capacitors. They have the lowest ESR (equivalent series resistance) and highest resonance frequency which makes them optimum for use with high frequency switching converters. When selecting a ceramic capacitor, only X5R and X7R dielectric types should be used. Other types such as Z5U and Y5F have such severe loss of capacitance due to effects of temperature variation and applied voltage, they may provide as little as 20% of rated capacitance in many typical applications. Always consult capacitor manufacturer’s data curves before selecting a capacitor. High-quality ceramic capacitors can be obtained from Taiyo-Yuden, AVX, and Murata.

Table 1. Bill of Materials (Circuit 1, VIN = 12 V±10%, Output1 = 1.2 V/2 A, Output2 = 2.5 V/2 A)

PART DESCRIPTION PART VALUES PHYSICAL SIZE PART NUMBER MANUFACTURER
C1 Capacitor, Ceramic 10 µF, 16 V, X5R 1210 GRM32DR61C106KA01 Murata
C2 Capacitor, Ceramic 0.22 µF, 16 V, X5R 0603 EMK107BJ224KA-T Taiyo Yuden
C3 Capacitor, Ceramic 0.1 µF, 6.3 V, X5R 0402 C1005X5R0J104K TDK
C4 Capacitor, Ceramic 0.1 µF, 6.3 V, X5R 0402 C1005X5R0J104K TDK
C5 Capacitor, Ceramic 100 µF, 6.3 V, X5R 1210 GRM32ER60J107ME20L Murata
C6 Capacitor, Ceramic 47 µF, 6.3 V, X5R 1210 GRM32ER60J476ME20L Murata
C7 Capacitor, Ceramic 0.012 µF, 6.3 V, X5R 0402 C0402C123K9PACTU Kemet
C8 Capacitor, Ceramic 0.012 µF, 6.3 V, X5R 0402 C0402C123K9PACTU Kemet
C9 Capacitor, Ceramic 0.027 µF, 6.3 V, X5R 0402 C0402C273K9PACTU Kemet
C10 Capacitor, Ceramic 0.027 µF, 6.3 V, X5R 0402 C0402C273K9PACTU Kemet
D1 Diode, Schottky 2 A, 30 V SMB MBRS230LT3G ON Semiconductor
D2 Diode, Schottky 2 A, 30 V SMB MBRS230LT3G ON Semiconductor
L1 Inductor 5 µH, 2.2 A 7 × 7 × 2.8 mm3 CDRH6D26NP-5R0NC Sumida
L2 Inductor 8.7 µH, 2.2 A 7 × 7 × 4 mm3 CDRH6D38NP-8R7NC Sumida
R1 Resistor 10 Ω, 1% 0402 CRCW040210R0FK Vishay
R2 Resistor 5.9 kΩ, 1% 0402 CRCW04025K90FK Vishay
R3 Resistor 5.9 kΩ, 1% 0402 CRCW04025K90FK Vishay
R4 Resistor 18.7 kΩ, 1% 0402 CRCW040218K7FK Vishay
R5 Resistor 5.9 kΩ, 1% 0402 CRCW04025K90FK Vishay
U1 Regulator Dual 2-A Buck HTSSOP-16 LM26400YMH Texas Instruments

Table 2. Bill of Materials (Circuit 1, VIN = 7 V to 20 V, Output1 = 3.3 V/2 A, Output2 = 5 V/2 A)

PART DESCRIPTION PART VALUES PHYSICAL SIZE PART NUMBER MANUFACTURER
C1 Capacitor, Ceramic 10 µF, 25 V, X5R 1812 GRM43DR61E106KA12 Murata
C2 Capacitor, Ceramic 0.22 µF, 25 V, X5R 0603 TMK107BJ224KA-T Taiyo Yuden
C3 Capacitor, Ceramic 0.1 µF, 6.3 V, X5R 0402 C1005X5R0J104K TDK
C4 Capacitor, Ceramic 0.1 µF, 6.3 V, X5R 0402 C1005X5R0J104K TDK
C5 Capacitor, Ceramic 47 µF, 6.3 V, X5R 1210 GRM32ER60J476ME20 Murata
C6 Capacitor, Ceramic 33 µF, 6.3 V, X5R 1210 GRM32DR60J336ME19 Murata
C7 Capacitor, Ceramic 0.012 µF, 6.3 V, X5R 0402 C0402C123K9PACTU Kemet
C8 Capacitor, Ceramic 0.012 µF, 6.3 V, X5R 0402 C0402C123K9PACTU Kemet
C9 Capacitor, Ceramic 0.027 µF, 6.3 V, X5R 0402 C0402C273K9PACTU Kemet
C10 Capacitor, Ceramic 0.027 µF, 6.3 V, X5R 0402 C0402C273K9PACTU Kemet
D1 Diode, Schottky 2 A, 30 V SMB MBRS230LT3G ON Semiconductor
D2 Diode, Schottky 2 A, 30 V SMB MBRS230LT3G ON Semiconductor
L1 Inductor 10 µH, 3 A 8.3 × 8.3 × 4 mm3 CDRH8D38NP-100NC Sumida
L2 Inductor 15 µH, 3 A 8.3 × 8.3 × 4 mm3 CDRH8D43/HP-150NC Sumida
R1 Resistor 10 Ω, 1% 0402 CRCW040210R0FK Vishay
R2 Resistor 26.7 kΩ, 1% 0402 CRCW040226K7FK Vishay
R3 Resistor 5.9 kΩ, 1% 0402 CRCW04025K90FK Vishay
R4 Resistor 43.2 kΩ, 1% 0402 CRCW040218K7FK Vishay
R5 Resistor 5.9 kΩ, 1% 0402 CRCW04025K90FK Vishay
U1 Regulator Dual 2-A Buck HTSSOP-16 LM26400YMH Texas Instruments

8.2.1.3 Application Curves

LM26400Y 20200223.png Figure 28. Load Step Response
LM26400Y 20200228.png Figure 30. Start-Up (No Load)
LM26400Y 20200224.png Figure 29. Load Step Response
LM26400Y 20200239.png Figure 31. Start-Up (No Load)

8.2.2 LM26400Y Design Example 2

LM26400Y 20200255.png

Table 3. Bill of Materials (Circuit 2, VIN = 3 V to 5 V, Output1 = 1.2 V/2 A, Output2 = 1.8 V/2 A)

PART DESCRIPTION PART VALUES PHYSICAL SIZE PART NUMBER MANUFACTURER
C1 Capacitor, Ceramic 10 µF, 6.3 V, X5R 1206 GRM319R60J106KE19 Murata
C2 Capacitor, Ceramic 0.22 µF, 6.3 V, X5R 0402 JMK105BJ224KV-F Taiyo Yuden
C3 Capacitor, Ceramic 0.1 µF, 6.3 V, X5R 0402 C1005X5R0J104K TDK
C4 Capacitor, Ceramic 0.1 µF, 6.3 V, X5R 0402 C1005X5R0J104K TDK
C5 Capacitor, Ceramic 100 µF, 6.3 V, X5R 1210 GRM32ER60J107ME20L Murata
C6 Capacitor, Ceramic 100 µF, 6.3 V, X5R 1210 GRM32ER60J107ME20L Murata
C7 Capacitor, Ceramic 0.012 µF, 6.3 V, X5R 0402 C0402C123K9PACTU Kemet
C8 Capacitor, Ceramic 0.012 µF, 6.3 V, X5R 0402 C0402C123K9PACTU Kemet
C9 Capacitor, Ceramic 0.027 µF, 6.3 V, X5R 0402 C0402C273K9PACTU Kemet
C10 Capacitor, Ceramic 0.027 µF, 6.3 V, X5R 0402 C0402C273K9PACTU Kemet
D1 Diode, Schottky 2 A, 30 V SMB MBRS230LT3G ON Semiconductor
D2 Diode, Schottky 2 A, 30 V SMB MBRS230LT3G ON Semiconductor
L1 Inductor 5 µH, 2.2 A 7 × 7 × 2.8 mm3 CDRH6D26NP-5R0NC Sumida
L2 Inductor 5 µH, 2.2 A 7 × 7 × 2.8 mm3 CDRH6D26NP-5R0NC Sumida
R1 Resistor 10 Ω, 1% 0402 CRCW040210R0FK Vishay
R2 Resistor 5.9 kΩ, 1% 0402 CRCW04025K90FK Vishay
R3 Resistor 5.9 kΩ, 1% 0402 CRCW04025K90FK Vishay
R4 Resistor 11.8 kΩ, 1% 0402 CRCW040211K8FK Vishay
R5 Resistor 5.90 kΩ, 1% 0402 CRCW04025K90FK Vishay
U1 Regulator Dual 2-A Buck HTSSOP-16 LM26400YMH Texas Instruments