ZHCS547K January   2010  – February 2018 LM27402

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      典型应用电路
  4. 4 修订历史记录
  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 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Typical Performance Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Wide Input Voltage Range
      2. 7.3.2  UVLO
      3. 7.3.3  Precision Enable
      4. 7.3.4  Soft-Start and Voltage Tracking
      5. 7.3.5  Output Voltage Setpoint and Accuracy
      6. 7.3.6  Voltage-Mode Control
      7. 7.3.7  Power Good
      8. 7.3.8  Inductor-DCR-Based Overcurrent Protection
      9. 7.3.9  Current Sensing
      10. 7.3.10 Power MOSFET Gate Drivers
      11. 7.3.11 Pre-Bias Start-up
    4. 7.4 Device Functional Modes
      1. 7.4.1 Fault Conditions
        1. 7.4.1.1 Thermal Protection
        2. 7.4.1.2 Current Limit
        3. 7.4.1.3 Negative Current Limit
        4. 7.4.1.4 Undervoltage Threshold (UVT)
        5. 7.4.1.5 Overvoltage Threshold (OVT)
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1  Converter Design
      2. 8.1.2  Inductor Selection (L)
      3. 8.1.3  Output Capacitor Selection (COUT)
      4. 8.1.4  Input Capacitor Selection (CIN)
      5. 8.1.5  Using Precision Enable
      6. 8.1.6  Setting the Soft-Start Time
      7. 8.1.7  Tracking
      8. 8.1.8  Setting the Switching Frequency
      9. 8.1.9  Setting the Current Limit Threshold
      10. 8.1.10 Control Loop Compensation
      11. 8.1.11 MOSFET Gate Drivers
      12. 8.1.12 Power Loss and Efficiency Calculations
        1. 8.1.12.1 Power MOSFETs
        2. 8.1.12.2 High-Side Power MOSFET
        3. 8.1.12.3 Low-Side Power MOSFET
        4. 8.1.12.4 Gate-Charge Loss
        5. 8.1.12.5 Input and Output Capacitor ESR Losses
        6. 8.1.12.6 Inductor Losses
        7. 8.1.12.7 Controller Losses
        8. 8.1.12.8 Overall Efficiency
    2. 8.2 Typical Applications
      1. 8.2.1 Example Circuit 1
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Custom Design With WEBENCH® Tools
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Example Circuit 2
      3. 8.2.3 Example Circuit 3
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Power Stage Layout
      2. 10.1.2 Gate Drive Layout
      3. 10.1.3 Controller Layout
      4. 10.1.4 Thermal Design and Layout
    2. 10.2 Layout Example
  11. 11器件和文档支持
    1. 11.1 器件支持
      1. 11.1.1 第三方产品免责声明
      2. 11.1.2 开发支持
        1. 11.1.2.1 使用 WEBENCH® 工具创建定制设计
    2. 11.2 文档支持
      1. 11.2.1 相关文档
    3. 11.3 接收文档更新通知
    4. 11.4 社区资源
    5. 11.5 商标
    6. 11.6 静电放电警告
    7. 11.7 Glossary
  12. 12机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

8.2.2 Example Circuit 2

LM27402 30092695.gifFigure 46. 5-V to 12-V Input Voltage Range, 3.3-V Output, 25-A Output Current, 300-kHz Switching Frequency

Table 2. Bill Of Materials

DESIGNATOR TYPE PARAMETERS PART NUMBER QTY MANUFACTURER
U1 IC Synchronous Buck Voltage-Mode PWM Controller LM27402 1 TI
CBOOT Capacitor 0.22 µF, Ceramic, X7R, 25 V, 10% GRM188R71E224KA88D 1 Murata
CC1 Capacitor 1200 pF, Ceramic, COG, 50 V, 5% GRM1885C1H122JA01D 1 Murata
CC2 Capacitor 56 pF, Ceramic, COG, 50 V, 5% GRM1885C1H560JA01D 1 Murata
CC3 Capacitor 820 pF, Ceramic, COG, 50 V, 5% GRM1885C1H821JA01D 1 Murata
CVDD Capacitor 1 µF, Ceramic, X5R, 25 V, 10% GRM188R61E105KA12D 1 Murata
CF Capacitor 1 µF, Ceramic, X5R, 25 V, 10% GRM188R61E105KA12D 1 Murata
CIN Capacitor 22 µF, Ceramic, X5R, 25 V, 10% GRM32ER61E226KE15L 5 Murata
COUT 1 Capacitor 100 µF, Ceramic, X5R, 6.3 V, 20% C1210C107M9PACTU 1 Kemet
COUT2 Capacitor 330 µF, POSCAP, 6.3 V, 20% 6TPE1330MIL 1 Sanyo
CS Capacitor 0.22 µF, Ceramic, X7R, 25 V, 10% GRM188R71E224KA88D 1 Murata
CSS Capacitor 47000 pF, Ceramic, X7R, 16 V, 10% GRM188R71E473KA01D 1 Murata
CSBY Capacitor 100 pF, Ceramic, C0G, 50 V, 5% GRM1885C1H101JA01D 1 Murata
DBOOT Diode Schottky Diode, Average I = 100 mA, Max Surge I = 750 mA CMOSH-3 1 Central Semi
DSW Diode Schottky Diode, Average I = 3 A, Max Surge I = 80A CMSH3-40M 1 Central Semi
LOUT Inductor 1 µH, 0.9 mΩ SER2010-102ML 1 Coilcraft
QL N-CH MOSFET 30 V, 60 A, 43.5 nC, RDS(on) at 4.5V = 1.85 mΩ Si7192DP 1 Vishay
QH(1,2) N-CH MOSFET 25 V, 50 A, 20 nC, RDS(on) at 4.5V = 3.4 mΩ SiR892DP 1 Vishay
RC1 Resistor 18.7 kΩ, 1%, 0.1 W CRCW060318K7FKEA 1 Vishay
RC2 Resistor 4.75 kΩ, 1%, 0.1 W CRCW06034K75FKEA 1 Vishay
RFADJ Resistor 45.3 kΩ, 1%, 0.1 W CRCW060345K3FKEA 1 Vishay
RFB1 Resistor 20.0 kΩ, 1%, 0.1 W CRCW060320K0FKEA 1 Vishay
RFB2 Resistor 4.42 kΩ, 1%, 0.1 W CRCW06034K42FKEA 1 Vishay
RF Resistor 2.2Ω, 5%, 0.1 W CRCW06032R20JNEA 1 Vishay
RPGD Resistor 51.1 kΩ, 5%, 0.1 W CRCW060351K1JNEA 1 Vishay
RS Resistor 4.12 kΩ, 1%, 0.1 W CRCW06034K12FKEA 1 Vishay
RSET Resistor 4.53 kΩ, 1%, 0.1 W CRCW06034K53FKEA 1 Vishay