ZHCSCW5B August   2014  – September 2017 LM43600

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 简化电路原理图
    1.     5
    2.     辐射发射图VIN = 12V，VOUT = 3.3V，FSW= 500kHz，IOUT = 0.5A
  5. 5 修订历史记录
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 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 Switching Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Fixed Frequency Peak Current Mode Controlled Step-Down Regulator
      2. 8.3.2  Light Load Operation
      3. 8.3.3  Adjustable Output Voltage
      4. 8.3.4  Enable (ENABLE)
      5. 8.3.5  VCC, UVLO and BIAS
      6. 8.3.6  Soft Start and Voltage Tracking (SS/TRK)
      7. 8.3.7  Switching Frequency (RT) and Synchronization (SYNC)
      8. 8.3.8  Minimum ON-Time, Minimum OFF-Time and Frequency Foldback at Dropout Conditions
      9. 8.3.9  Internal Compensation and CFF
      10. 8.3.10 Bootstrap Voltage (BOOT)
      11. 8.3.11 Power Good (PGOOD)
      12. 8.3.12 Overcurrent and Short-Circuit Protection
      13. 8.3.13 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Stand-by Mode
      3. 8.4.3 Active Mode
      4. 8.4.4 CCM Mode
      5. 8.4.5 Light Load Operation
      6. 8.4.6 Self-Bias Mode
  9. 9 Applications and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1  Custom Design With WEBENCH® Tools
        2. 9.2.2.2  Output Voltage Setpoint
        3. 9.2.2.3  Switching Frequency
        4. 9.2.2.4  Input Capacitors
        5. 9.2.2.5  Inductor Selection
        6. 9.2.2.6  Output Capacitor Selection
        7. 9.2.2.7  Feedforward Capacitor
        8. 9.2.2.8  Bootstrap Capacitors
        9. 9.2.2.9  VCC Capacitor
        10. 9.2.2.10 BIAS Capacitors
        11. 9.2.2.11 Soft-Start Capacitors
        12. 9.2.2.12 Undervoltage Lockout Setpoint
        13. 9.2.2.13 PGOOD
      3. 9.2.3 Application Performance Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Compact Layout for EMI Reduction
      2. 11.1.2 Ground Plane and Thermal Considerations
      3. 11.1.3 Feedback Resistors
    2. 11.2 Layout Example
  12. 12器件和文档支持
    1. 12.1 开发支持
      1. 12.1.1 使用 WEBENCH® 工具创建定制设计
    2. 12.2 接收文档更新通知
    3. 12.3 社区资源
    4. 12.4 商标
    5. 12.5 静电放电警告
    6. 12.6 Glossary
  13. 13机械、封装和可订购信息

封装选项

请参考 PDF 数据表获取器件具体的封装图。

机械数据 (封装 | 引脚)
  • PWP|16
散热焊盘机械数据 (封装 | 引脚)
订购信息

9.2 Typical Applications

The LM43600 only requires a few external components to convert from a wide range of supply voltage to output voltage. Figure 44 shows a basic schematic when BIAS is connected to VOUT. This is recommended for VOUT ≥ 3.3 V. For VOUT< 3.3 V, connect the BIAS pin to ground, as shown in Figure 45.

LM43600 Sch_basic01.gifFigure 44. LM43600 Basic Schematic for
VOUT ≥ 3.3 V, Tie BIAS to VOUT
LM43600 Sch_basic02.gifFigure 45. LM43600 Basic Schematic for
VOUT< 3.3 V, Tie BIAS to Ground

The LM43600 also integrates a full list of optional features to aid system design requirements, such as precision enable, VCC UVLO, programmable soft-start, output voltage tracking, programmable switching frequency, clock synchronization and power-good indication. Each application can select the features for a more comprehensive design. A schematic with all features utilized is shown in Figure 46.

LM43600 Sch_full_feature.gif
Figure 46. LM43600 Schematic with All Features

The external components have to fulfill the needs of the application, but also the stability criteria of the device's control loop. The LM43600 is optimized to work within a range of external components. The LC output filter's inductance and capacitance have to be considered in conjunction, creating a double pole, responsible for the corner frequency of the converter. Table 2 can be used to simplify the output filter component selection.

Table 2. L, COUT and CFF Typical Values

FS (kHz) L (µH)(1) COUT (µF) (2) CFF (pF) (3)(4) RT (kΩ) RFBB (kΩ) (3)(4)
VOUT = 1 V
200 22 500 none 200 100
500 10 330 none 80.6 or open 100
1000 4.8 180 none 39.2 100
2200 2.2 100 none 17.8 100
VOUT = 3.3 V
200 68 220 44 200 442
500 22 100 33 80.6 or open 442
1000 15 47 18 39.2 442
2200 6.8 27 12 17.8 442
VOUT = 5 V
200 82 150 68 200 255
500 33 66 33 80.6 or open 255
1000 18 33 22 39.2 255
2200 6.8 22 18 17.8 255
VOUT = 12 V
200 150 33 see note (5) 200 90.9
500 56 22 47 80.6 or open 90.9
1000 27 15 33 39.2 90.9
(1) Inductor values are calculated based on typical VIN = 12 V. For VOUT = 12 V, typical VIN = 24 V.
(2) All the COUT values are after derating. Add more when using ceramics
(3) RFBT = 0 Ω for VOUT = 1 V. RFBT = 1 MΩ for all other VOUT settings.
(4) For designs with RFBT other than 1 MΩ, adjust CFF such that (CFF × RFBT) is unchanged and adjust RFBB such that (RFBT / RFBB) is unchanged.
(5) High ESR COUT gives enough phase boost, and CFF not needed.