ZHCSCW5B August   2014  – September 2017 LM43600

PRODUCTION DATA.  

  1. 特性
  2. 应用
  3. 说明
  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. 修订历史记录
  6. Pin Configuration and Functions
    1.     Pin Functions
  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. 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. 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

Electrical Characteristics

Limits apply over the recommended operating junction temperature (TJ) range of –40°C to 125°C, unless otherwise stated. Minimum and Maximum limits are specified through test, design or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only. Unless otherwise stated, the following conditions apply: VIN = 12 V, VOUT = 3.3 V, FS = 500 kHz.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
SUPPLY VOLTAGE (VIN PINS)
VIN-MIN-ST Minimum input voltage for start-up 3.8 V
ISHDN Shutdown quiescent current VEN = 0 V 1.1 3.1 µA
IQ-NONSW Operating quiescent current (non-switching) from VIN VEN = 3.3 V
VFB = 1.5 V
VBIAS = 3.4 V external
6 11 µA
IBIAS-NONSW Operating quiescent current (non-switching) from external VBIAS VEN = 3.3 V
VFB = 1.5 V
VBIAS = 3.4 V external
85 140 µA
IQ-SW Operating quiescent current (switching) VEN = 3.3 V
IOUT = 0 A
RT = open
VBIAS = VOUT = 3.3 V
RFBT = 1 Meg
33 µA
ENABLE (EN PIN)
VEN-VCC-H Voltage level to enable the internal LDO output VCC VENABLE high level 1.2 V
VEN-VCC-L Voltage level to disable the internal LDO output VCC VENABLE low level 0.4 V
VEN-VOUT-H Precision enable level for switching and regulator output: VOUT VENABLE high level 2 2.1 2.42 V
VEN-VOUT-HYS Hysteresis voltage between VOUT precision enable and disable thresholds VENABLE hysteresis –305 mV
ILKG-EN Enable input leakage current VEN = 3.3 V 0.8 1.75 µA
INTERNAL LDO (VCC PIN AND BIAS PIN)
VCC Internal LDO output voltage VCC VIN ≥ 3.8 V 3.3 V
VCC-UVLO Undervoltage lockout (UVLO) thresholds for VCC VCC rising threshold 3.14 V
Hysteresis voltage between rising and falling thresholds –567 mV
VBIAS-ON Internal LDO input change over threshold to BIAS VBIAS rising threshold 2.96 3.2 V
Hysteresis voltage between rising and falling thresholds –74 mV
VOLTAGE REFERENCE (FB PIN)
VFB Feedback voltage TJ = 25°C 1.009 1.016 1.023 V
TJ = –40°C to 85°C 0.999 1.016 1.031
TJ = –40°C to 125°C 0.999 1.016 1.039
ILKG-FB Input leakage current at FB pin FB = 1.011 V 0.2 65 nA
THERMAL SHUTDOWN
TSD(1) Thermal shutdown Shutdown threshold 160 °C
Recovery threshold 150 °C
CURRENT LIMIT AND HICCUP
IHS-LIMIT Peak inductor current limit 1.04 1.33 1.56 A
ILS-LIMIT Inductor current valley limit 0.46 0.60 0.75 A
SOFT START (SS/TRK PIN)
ISSC Soft-start charge current 1.17 2.2 2.85 µA
RSSD Soft-start discharge resistance UVLO, TSD, OCP, or EN = 0 V 16
POWER GOOD (PGOOD PIN)
VPGOOD-HIGH Power-good flag overvoltage tripping threshold % of FB voltage 110% 113%
VPGOOD-LOW Power-good flag undervoltage tripping threshold % of FB voltage 83% 90%
VPGOOD-HYS Power-good flag recovery hysteresis % of FB voltage 6%
RPGOOD PGOOD pin pulldown resistance when power bad VEN = 3.3 V 40 125 Ω
VEN = 0 V 60 150
MOSFETS (2)
RDS-ON-HS High-side MOSFET ON-resistance IOUT = 0.5 A
VBIAS = VOUT = 3.3 V
419
RDS-ON-LS Low-side MOSFET ON-resistance IOUT = 0.5 A
VBIAS = VOUT = 3.3 V
231
Specified by design.
Measured at package pins.