ZHCSD59F June   2012  – November 2017 LM34926

PRODUCTION DATA.  

  1. 特性
  2. 应用
  3. 说明
    1.     Device Images
      1.      典型应用
  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 Ratings
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Switching Characteristics
    7. 6.7 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Control Overview
      2. 7.3.2  VCC Regulator
      3. 7.3.3  Regulation Comparator
      4. 7.3.4  Overvoltage Comparator
      5. 7.3.5  On-Time Generator
      6. 7.3.6  Current Limit
      7. 7.3.7  N-Channel Buck Switch and Driver
      8. 7.3.8  Synchronous Rectifier
      9. 7.3.9  Undervoltage Detector
      10. 7.3.10 Thermal Protection
      11. 7.3.11 Ripple Configuration
      12. 7.3.12 Soft Start
    4. 7.4 Device Functional Modes
  8. Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      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  Transformer Turns Ratio
        3. 8.2.2.3  Total IOUT
        4. 8.2.2.4  RFB1, RFB2
        5. 8.2.2.5  Frequency Selection
        6. 8.2.2.6  Transformer Selection
        7. 8.2.2.7  Primary Output Capacitor
        8. 8.2.2.8  Secondary Output Capacitor
        9. 8.2.2.9  Type III Feedback Ripple Circuit
        10. 8.2.2.10 Secondary Diode
        11. 8.2.2.11 VCC and Bootstrap Capacitor
        12. 8.2.2.12 Input Capacitor
        13. 8.2.2.13 UVLO Resistors
        14. 8.2.2.14 VCC Diode
      3. 8.2.3 Application Curves
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    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 开发支持
        1. 11.1.1.1 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

Pin Configuration and Functions

DDA Package
8-Pin HSOP
Top View
LM34926 hsoppin_snvs847.gif
NGU Package
8-Pin WSON
Top View
LM34926 Package outline - WSON.gif

Pin Functions

PINI/ODESCRIPTIONAPPLICATION INFORMATION
NO.NAME
1 RTN Ground Ground connection of the integrated circuit.
2 VIN I Input Voltage Operating input range is 7.5 V to 100 V.
3 UVLO I Input Pin of Undervoltage Comparator Resistor divider from VIN to UVLO to GND programs the undervoltage detection threshold. An internal current source is enabled when UVLO is above 1.225 V to provide hysteresis. When UVLO pin is pulled below 0.66 V externally, the parts goes in shutdown mode.
4 RON I On-Time Control A resistor between this pin and VIN sets the switch on-time as a function of VIN. Minimum recommended on-time is 100 ns at max input voltage.
5 FB I Feedback This pin is connected to the inverting input of the internal regulation comparator. The regulation level is 1.225 V.
6 VCC O Output from the Internal High Voltage Series Pass Regulator.
Regulated at 7.6 V.
The internal VCC regulator provides bias supply for the gate drivers and other internal circuitry. A 1.0-μF decoupling capacitor is recommended.
7 BST I Bootstrap Capacitor An external capacitor is required between the BST and SW pins (0.01-μF ceramic). The BST pin capacitor is charged by the VCC regulator through an internal diode when the SW pin is low.
8 SW O Switching Node Power switching node. Connect to the output inductor and bootstrap capacitor.
EP Exposed Pad Exposed pad must be connected to RTN pin. Connect to system ground plane on application board for reduced thermal resistance.