SLLSFM0A March   2022  – June 2022 SN6507

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Switching Characteristics
    7. 6.7 Typical Characteristics, SN6507
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Push-Pull Converter
      2. 8.3.2 Core Magnetization
      3. 8.3.3 Duty Cycle Control
      4.      Programmable Switching Frequency
      5. 8.3.4 Spread Spectrum Clocking
      6. 8.3.5 Slew Rate Control
      7. 8.3.6 Protection Features
        1. 8.3.6.1 Over Voltage Protection (OVP)
        2. 8.3.6.2 Over Current and Short Circuit Protection (OCP)
        3. 8.3.6.3 Under Voltage Lock-Out (UVLO)
        4. 8.3.6.4 Thermal Shut Down (TSD)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Start-Up Mode
        1. 8.4.1.1 Soft-Start
      2. 8.4.2 Operation Mode
      3. 8.4.3 Shutdown Mode
      4. 8.4.4 SYNC Mode
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Pin Configuration
        2. 9.2.2.2 LDO Selection
        3. 9.2.2.3 Diode Selection
        4. 9.2.2.4 Capacitor and Inductor Selection
        5. 9.2.2.5 Transformer Selection
          1. 9.2.2.5.1 V-t Product Calculation
          2. 9.2.2.5.2 Turns Ratio Estimate
        6. 9.2.2.6 Low-Emissions Designs
      3. 9.2.3 Application Curves
      4. 9.2.4 System Examples
        1. 9.2.4.1 Higher Output Voltage Designs
        2. 9.2.4.2 Commercially-Available Transformers
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  10. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Community Resources
    4. 10.4 Trademarks
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

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

9.1 Application Information

The SN6507 is a transformer driver designed for low-cost, small form-factor, isolated DC/DC converters using the push-pull topology. The device includes an oscillator that feeds a gate-drive circuit. The gate-drive, comprising a frequency divider and a break-before-make (BBM) logic, provides two complementary output signals which alternately turn the two output transistors on and off.

Figure 9-1 Block Diagram With Break-Before-Make Action
Figure 9-2 Output timing with Break-Before-Make Action

The output frequency of the oscillator is divided down by an asynchronous divider that provides two complementary output signals, S and S, with a 50% duty cycle. A subsequent break-before-make logic inserts a dead-time between the high-pulses of the two signals. The resulting output signals, G1 and G2, present the gate-drive signals for the output transistors Q1 and Q2. As shown in Figure 9-2, before either one of the gates can assume logic high, there must be a short time period during which both signals are low and both transistors are high-impedance. This short period, known as break-before-make time, is required to avoid shorting out both ends of the primary.