SLUS456F April   1999  – July 2018 UCC2808A-1 , UCC2808A-2 , UCC3808A-1 , UCC3808A-2

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Application
  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 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 Pin Descriptions
        1. 7.3.1.1 COMP
        2. 7.3.1.2 CS
        3. 7.3.1.3 FB
        4. 7.3.1.4 GND
        5. 7.3.1.5 OUTA and OUTB
        6. 7.3.1.6 RC
        7. 7.3.1.7 VDD
    4. 7.4 Device Functional Modes
      1. 7.4.1 VCC
      2. 7.4.2 Push-Pull or Half-Bridge Function
  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
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Related Links
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • D|8
  • PW|8
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.1.6 RC

The oscillator programming pin. The oscillator of the UCC3808-x tracks VDD and GND internally, so that variations in power supply rails minimally affect frequency stability. Figure 10 shows the oscillator block diagram.

Only two components are required to program the oscillator: a resistor (tied to the VDD and RC), and a capacitor (tied to the RC and GND). The approximate oscillator frequency is determined by Equation 1.

Equation 1. UCC2808A-1 UCC2808A-2 UCC3808A-1 UCC3808A-2 equation_02_slus168.gif

where

  • frequency is in Hz
  • resistance in Ω
  • capacitance in Farads

The recommended range of timing resistors is between 10 kΩ and 200 kΩ and range of timing capacitors is between 100 pF and 1000 pF. Timing resistors less than 10 kΩ must be avoided.

For best performance, keep the timing capacitor lead to GND as short as possible, the timing resistor lead from VDD as short as possible, and the leads between timing components and RC as short as possible. Separate ground and VDD traces to the external timing network are encouraged.