SLUS652E March   2005  – April 2020 UCD8220

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1. 3.1 UCD8220 Typical Simplified Push-Pull Converter Application Schematic
  4. 4 Revision History
  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 Timing Requirements
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 CLK Input Time-Domain Digital Pulse Train
      2. 7.3.2 Current Sensing and Protection
      3. 7.3.3 Handshaking
      4. 7.3.4 Driver Output
      5. 7.3.5 Source and Sink Capabilities During Miller Plateau
      6. 7.3.6 Drive Current and Power Requirements
      7. 7.3.7 Clearing the Current-Limit Flag (CLF)
    4. 7.4 Device Functional Modes
  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 Selecting the ISET Resistor for Voltage Mode Control
        2. 8.2.2.2 Selecting the ISET Resistor for Voltage Mode Control with Voltage Feed Forward
        3. 8.2.2.3 Selecting the ISET Resistor for Peak Current Mode Control with Internal Slope Compensation
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable 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)
  • PWP|16
散热焊盘机械数据 (封装 | 引脚)
订购信息

8.2.2.1 Selecting the ISET Resistor for Voltage Mode Control

UCD8220 iset_vmc_slusb36.gifFigure 31. UCD8220 Configured in Voltage Mode Control With an Internal Timing Capacitor

When the ISET resistor is configured as shown in Figure 31 with the ISET resistor connected between the ISET pin and the 3V3 pin, the device is set up for voltage mode control. For purposes of voltage loop compensation the, voltage ramp is 1.4 V from the valley to the peak. Use Equation 5 to calculate the proper resistance for a desired clock frequency.

Equation 5. UCD8220 q1_r_iset_slusb36.gif

where

  • fclk = desired clock frequency in Hz
UCD8220 isetres_v_freq_lus652.gifFigure 32. ISET Resistance Versus Clock Frequency

Figure 32 shows the nominal value of resistance to use for a desired clock frequency. For example, a clock frequency of 1000 kHz will require 10 kΩ of the ISET resistor. The UCD8220 device has two outputs controlled by push-pull logic and therefore the output ripple frequency is equal to the clock frequency and each output switches at half the clock frequency.