ZHCSY68D October   2008  – April 2025 LM5574-Q1

PRODUCTION DATA  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Shutdown and Standby
      2. 6.3.2 Current Limit
      3. 6.3.3 Soft Start
      4. 6.3.4 Thermal Protection
    4. 6.4 Device Functional Modes
      1. 6.4.1 High Voltage Start-Up Regulator
      2. 6.4.2 Oscillator and Sync Capability
      3. 6.4.3 Error Amplifier and PWM Comparator
      4. 6.4.4 Ramp Generator
      5. 6.4.5 Maximum Duty Cycle and Input Dropout Voltage
      6. 6.4.6 Boost Pin
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Bias Power Dissipation Reduction
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1  Custom Design With WEBENCH® Tools
        2. 7.2.2.2  External Components
        3. 7.2.2.3  R3 (RT)
        4. 7.2.2.4  L1- Inductor
        5. 7.2.2.5  C3- Ramp Capacitor
        6. 7.2.2.6  C9 -Output Capacitor
        7. 7.2.2.7  D1 - Async Diode
        8. 7.2.2.8  C1- Input Capacitor
        9. 7.2.2.9  C8 - Vcc Capacitor
        10. 7.2.2.10 C7 - BST Capacitor
        11. 7.2.2.11 C4 - SS Capacitor
        12. 7.2.2.12 R5, R6 - Feedback Resistor
        13. 7.2.2.13 R1, R2, C2 - SD Pin Components
        14. 7.2.2.14 R4, C5, C6 - Compensation Components
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
      3. 7.4.3 Power Dissipation
      4. 7.4.4 Thermal Considerations
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Development Support
        1. 8.1.1.1 Custom Design With WEBENCH® Tools
    2. 8.2 接收文档更新通知
    3. 8.3 支持资源
    4. 8.4 Trademarks
    5. 8.5 静电放电警告
    6. 8.6 术语表
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

5.5 Electrical Characteristics

Specifications with standard typeface are for TJ = 25°C, VIN = 48V, RT = 32.4kΩ unless otherwise stated.(1)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
STARTUP REGULATOR
VCC Reg VCC Regulator Output 6.85 7.15 7.45 V
VCC LDO Mode turn-off 9 V
VCC Current Limit VCC = 0 V, 25 mA
VCC SUPPLY
VCC UVLO Threshold (VCC increasing). 5.03 5.35 5.67 V
VCC Undervoltage Hysteresis 0.35 V
Bias Current (Iin) FB = 1.3 V. 2 4.5 mA
Shutdown Current (Iin) SD = 0 V. 48 85 µA
SHUTDOWN THRESHOLDS
Shutdown Threshold (SD Increasing) 0.47 0.7 0.9 V
Shutdown Hysteresis 0.1 V
Standby Threshold (Standby Increasing) 1.17 1.225 1.28 V
Standby Hysteresis 0.1 V
SD Pull-up Current Source 5 µA
SWITCH CHARACTERISTICS
Buck Switch Rds(on) 750 1500 mΩ
BOOST UVLO 4 V
BOOST UVLO Hysteresis  0.93 V
Pre-charge Switch Rds(on) 70 Ω
Pre-charge Switch on-time 250 ns
CURRENT LIMIT
Cycle by Cycle Current Limit RAMP = 0 V 0.6 0.7 0.8 A
Cycle by Cycle Current Limit Delay RAMP = 2.5 V 75 ns
SOFT-START
SS Current Source 7 10 14 µA
OSCILLATOR
Frequency1 180 200 220 kHz
Frequency2 RT = 11 kΩ. 425 485 525 kHz
SYNC Source Impedance 11 kΩ
SYNC Sink Impedance 110 Ω
SYNC Threshold (falling) 1.3 V
SYNC Frequency RT = 11 kΩ. 550 kHz
SYNC Pulse Width Minimum 15 ns
RAMP GENERATOR

Ramp Current 1		 VIN = 60 V, VOUT=10 V. 467 550 633 µA
Ramp Current 2 VIN = 10 V, VOUT=10 V. 36 50 64 µA
PWM COMPARATOR
Forced Off-time 416 500 575 ns
Min On-time 80 ns
COMP to PWM Comparator Offset 0.7 V
ERROR AMPLIFIER
Feedback Voltage Vfb = COMP. 1.207 1.225 1.243 V
FB Bias Current 10 nA
DC Gain 70 dB
COMP Sink / Source Current 3 mA
Unity Gain Bandwidth 3 MHz
DIODE SENSE RESISTANCE
DSENSE 250 mΩ
THERMAL SHUTDOWN
Tsd Thermal Shutdown Threshold 165 °C
Thermal Shutdown hysteresis 25 °C
(1) Min and Max limits are 100% production tested at 25°C. Limits over the operating temperature range are specified through correlation using Statistical Quality Control (SQC) methods. Limits are used to calculate Texas Instruments' Average Outgoing Quality Level (AOQL).