ZHCSCN3B June   2014  – March 2018 LM46000

PRODUCTION DATA.  

  1. 特性
  2. 应用
  3. 说明
    1.     Device Images
      1.      简化原理图
      2.      辐射发射图 VOUT = 3.3V,VIN = 24V,FS= 500kHz,IOUT = 0.5A
  4. 修订历史记录
  5. Pin Configuration and Functions
    1.     Pin Functions
  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 Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Fixed-Frequency, Peak-Current-Mode Controlled Step-Down Regulator
      2. 7.3.2  Light Load Operation
      3. 7.3.3  Adjustable Output Voltage
      4. 7.3.4  Enable (EN)
      5. 7.3.5  VCC, UVLO, and BIAS
      6. 7.3.6  Soft Start and Voltage Tracking (SS/TRK)
      7. 7.3.7  Switching Frequency (RT) and Synchronization (SYNC)
      8. 7.3.8  Minimum ON-Time, Minimum OFF-Time and Frequency Foldback at Dropout Conditions
      9. 7.3.9  Internal Compensation and CFF
      10. 7.3.10 Bootstrap Voltage (CBOOT)
      11. 7.3.11 Power Good (PGOOD)
      12. 7.3.12 Overcurrent and Short-Circuit Protection
      13. 7.3.13 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Standby Mode
      3. 7.4.3 Active Mode
      4. 7.4.4 CCM Mode
      5. 7.4.5 Light Load Operation
      6. 7.4.6 Self-Bias Mode
  8. Applications and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1  Custom Design With WEBENCH® Tools
        2. 8.2.2.2  Output Voltage Setpoint
        3. 8.2.2.3  Switching Frequency
        4. 8.2.2.4  Input Capacitors
        5. 8.2.2.5  Inductor Selection
        6. 8.2.2.6  Output Capacitor Selection
        7. 8.2.2.7  Feed-Forward Capacitor
        8. 8.2.2.8  Bootstrap Capacitors
        9. 8.2.2.9  VCC Capacitor
        10. 8.2.2.10 BIAS Capacitors
        11. 8.2.2.11 Soft-Start Capacitors
        12. 8.2.2.12 Undervoltage Lockout Setpoint
        13. 8.2.2.13 PGOOD
      3. 8.2.3 Application Performance Curves
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Compact Layout for EMI Reduction
      2. 10.1.2 Ground Plane and Thermal Considerations
      3. 10.1.3 Feedback Resistors
    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 使用 WEBENCH® 工具创建定制设计
    2. 11.2 接收文档更新通知
    3. 11.3 社区资源
    4. 11.4 商标
    5. 11.5 静电放电警告
    6. 11.6 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

Typical Characteristics

Unless otherwise specified, VIN = 24 V, VOUT = 3.3 V, FS = 500 kHz, L = 27 µH, COUT = 100 µF, CFF = 33 pF. See Application Performance Curves for Bill of Materials (BOM) for other VOUT and FS combinations.
LM46000 C002_Eff_46000_3p3V500k.png
VOUT = 3.3 V FS = 500 kHz
Figure 1. Efficiency
LM46000 C003_Eff_46000_5V500k.png
VOUT = 5 V FS = 500 kHz
Figure 3. Efficiency
LM46000 C007_Eff_46000_12V500k.png
VOUT = 12 V FS = 500 kHz
Figure 5. Efficiency
LM46000 C012_Reg_46000_3p3V500k.png
VOUT = 3.3 V FS = 500 kHz
Figure 7. VOUT Regulation
LM46000 C013_Reg_46000_5V500k.png
VOUT = 5 V FS = 500 kHz
Figure 9. VOUT Regulation
LM46000 C017_Reg_46000_12V500k.png
VOUT = 12 V FS = 500 kHz
Figure 11. VOUT Regulation
LM46000 C022_DO_46000_3p3V500k.png
VOUT = 3.3 V FS = 500 kHz
Figure 13. Dropout Curve
LM46000 C023_DO_46000_5V500k.png
VOUT = 5 V FS = 500 kHz
Figure 15. Dropout Curve
LM46000 C027_DO_46000_12V500k.png
VOUT = 12 V FS = 500 kHz
Figure 17. Dropout Curve
LM46000 46000_3V3_500kHz_Freq_Drop.png
VOUT = 3.3 V FS = 500 kHz
Figure 19. Switching Frequency vs VIN in Dropout Operation
LM46000 lm46000_3p3_500k_radiated.gif
VOUT = 3.3 V FS = 500 kHz IOUT = 0.5 A
Measured on the LM46000PWPEVM with default BOM. No input filter used.
Figure 21. Radiated EMI Curve
LM46000 46000_3p3_500k_Conducted.gif
VOUT = 3.3 V FS = 500 kHz IOUT = 0.5 A
Measured on the LM46000PWPEVM with default BOM. EVM input filter: Lin = 1 µH Cd = 47 µF CIN4 = 68 µF
Figure 23. Conducted EMI Curve
LM46000 Gen_Curve_On_Resistance.png
Figure 25. High-Side and Low-side On-Resistance vs Junction Temperature
LM46000 Gen_Curve_EN_Threshold.png
Figure 27. Enable Threshold vs Junction Temperature
LM46000 Gen_Curve_PG_Threshold.png
Figure 29. PGOOD Threshold vs Junction Temperature
LM46000 Gen_Curve_46000Curr_Lim.png
VIN = 24 V VOUT = 3.3 V FS = 500 kHz
Figure 31. Peak and Valley Current Limits vs Junction Temperature
LM46000 C004_Eff_46000_5V200k.png
VOUT = 5 V FS = 200 kHz
Figure 2. Efficiency
LM46000 C005_Eff_46000_5V1M.png
VOUT = 5 V FS = 1 MHz
Figure 4. Efficiency
LM46000 C008_Eff_46000_24V500k.png
VOUT = 24 V FS = 500 kHz
Figure 6. Efficiency
LM46000 C014_Reg_46000_5V200k.png
VOUT = 5 V FS = 200 kHz
Figure 8. VOUT Regulation
LM46000 C015_Reg_46000_5V1M.png
VOUT = 5 V FS = 1 MHz
Figure 10. VOUT Regulation
LM46000 C018_Reg_46000_24V500k.png
VOUT = 24 V FS = 500 kHz
Figure 12. VOUT Regulation
LM46000 C024_DO_46000_5V200k.png
VOUT = 5 V FS = 200 kHz
Figure 14. Dropout Curve
LM46000 C025_DO_46000_5V1M.png
VOUT = 5 V FS = 1 MHz
Figure 16. Dropout Curve
LM46000 C028_DO_46000_24V500k.png
VOUT = 24 V FS = 500 kHz
Figure 18. Dropout Curve
LM46000 46000_5V_1MHz_Freq_Drop.png
VOUT = 5 V FS = 1 MHz
Figure 20. Switching Frequency vs VIN in Dropout Operation
LM46000 lm46000_5_500k_radiated.gif
VOUT = 5 V FS = 500 kHz IOUT = 0.5 A
Measured on the LM46000PWPEVM with L = 44 µH, COUT = 66 µF, CFF = 33 pF. No input filter used.
Figure 22. Radiated EMI Curve
LM46000 46000_5_500k_Conducted.gif
VOUT = 5 V FS = 500 kHz IOUT = 0.5 A
Measured on the LM46000PWPEVM with L = 44 µH, COUT = 66 µF, CFF = 33 pF. EVM input filter Lin = 1 µH Cd = 47 µF CIN4 = 68 µF
Figure 24. Conducted EMI Curve
LM46000 Gen_Curve_Shdn_Current.png
Figure 26. Shutdown Current vs Junction Temperature
LM46000 Gen_Curve_EN_Leakage_Curr.png
Figure 28. Enable Leakage Current vs
Junction Temperature
LM46000 Gen_Curve_FB_Voltage.png
Figure 30. Feedback Voltage vs Junction Temperature
LM46000 Gen_Curve_46000Iq.png
VOUT = 3.3 V FS = 500 kHz IOUT = 0 A
Figure 32. Operating IQ vs VIN With BIAS Connected to VOUT