ZHCSD26E August   2012  – August 2018 LMZ21701

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      简化原理图
      2.      VIN = 12V 时的效率
  4. 4 修订历史记录
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Package Construction
    4. 7.4 Feature Description
      1. 7.4.1 Input Undervoltage Lockout
      2. 7.4.2 Enable Input (EN)
      3. 7.4.3 Soft Start and Tracking Function (SS)
      4. 7.4.4 Power Good Function (PG)
      5. 7.4.5 Output Voltage Setting
      6. 7.4.6 Output Current Limit and Output Short Circuit Protection
      7. 7.4.7 Thermal Protection
    5. 7.5 Device Functional Modes
      1. 7.5.1 PWM Mode Operation
      2. 7.5.2 PSM Operation
  8. 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 Input Capacitor (CIN)
        3. 8.2.2.3 Output Capacitor (COUT)
        4. 8.2.2.4 Soft-start Capacitor (CSS)
        5. 8.2.2.5 Power Good Resistor (RPG)
        6. 8.2.2.6 Feedback Resistors (RFBB and RFBT)
      3. 8.2.3 Application Curves
        1. 8.2.3.1 VOUT = 1.2 V
        2. 8.2.3.2 VOUT = 1.8 V
        3. 8.2.3.3 VOUT = 2.5 V
        4. 8.2.3.4 VOUT = 3.3 V
        5. 8.2.3.5 VOUT = 5.0 V
    3. 8.3 Do's and Don'ts
  9. 9 Power Supply Recommendations
    1. 9.1 Voltage Range
    2. 9.2 Current Capability
    3. 9.3 Input Connection
      1. 9.3.1 Voltage Drops
      2. 9.3.2 Stability
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Minimize the High di/dt Loop Area
      2. 10.1.2 Protect the Sensitive Nodes in the Circuit
      3. 10.1.3 Provide Thermal Path and Shielding
    2. 10.2 Layout Example
      1. 10.2.1 High Density Layout Example for Space Constrained Applications
        1. 10.2.1.1 35 mm² Solution Size (Single Sided)
  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 商标
    3. 11.3 静电放电警告
    4. 11.4 术语表
  12. 12机械、封装和可订购信息
    1. 12.1 Tape and Reel Information

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)
  • SIL|8
散热焊盘机械数据 (封装 | 引脚)
订购信息

8.2.2.2 Input Capacitor (CIN)

Low ESR multi-layer ceramic capacitors (MLCC) are recommended for the input capacitor of the LMZ21701. Using a ≥ 10 µF ceramic input capacitor in ≥ 0805 (2012 metric) case size with 25-V rating typically provides sufficient VIN bypass. Use of multiple capacitors can also be considered. Ceramic capacitors with X5R and X7R temperature characteristics are recommended. These provide an optimal balance between small size, cost, reliability, and performance for applications with limited space. The DC voltage bias characteristics of the capacitors must be considered when selecting the DC voltage rating and case size of these components. The effective capacitance of an MLCC is typically reduced by the DC voltage bias applied across its terminals. Selecting a part with larger capacitance, larger case size, or higher voltage rating can compensate for the capacitance loss due to the DC voltage bias effect. For example, a 10-µF, X7R, 25-V rated capacitor used under 12-V DC bias may have approximately 8-µF effective capacitance in a 1210 (3225 metric) case size and about 6 µF in a 1206 (3216 metric) case size. As another example, a 10-µF, X7R, 16-V rated capacitor in a 1210 (3225 metric) case size used at 12-V DC bias may have approximately 5.5 µF effective capacitance. Check the capacitor specifications published by the manufacturer.