SGLS183C August   2003  – July 2025 UCC2808A-1Q1 , UCC2808A-2Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configurations and Functions
  7. 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
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Pin Descriptions
        1. 7.3.1.1 COMP Pin
        2. 7.3.1.2 OUTA and OUTB Pins
        3. 7.3.1.3 RC Pin
        4. 7.3.1.4 VDD Pin
    4. 7.4 Device Functional Modes
      1. 7.4.1 VCC
      2. 7.4.2 Push-Pull or Half-Bridge Function
  9. 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
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

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

7.3.1.3 RC Pin

The oscillator of the UCC2808Ax-Q1 tracks VDD and GND internally, so that variations in power supply rails minimally affect frequency stability. Figure 7-2 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 calculated in:

Equation 1. f O S C I L L A T O R = 1.41 R C

where

  • Frequency is in hertz (Hz)
  • Resistance is in Ω
  • Capacitance is in farads (F)

The recommended range of timing resistors is between 10kΩ and 200kΩ and range of timing capacitors is between 100pF and 1000pF. Avoid timing resistors less than 10kΩ.

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

UCC2808A-1Q1 UCC2808A-2Q1 Block Diagram for Oscillator
A. The oscillator generates a sawtooth waveform on RC. During the RC rise time, the output stages alternate on time, but both stages are off during the RC fall time. The output stages switch a 1/2 the oscillator frequency, with verified duty cycle of < 50% for both outputs.
Figure 7-2 Block Diagram for Oscillator