SLUSCJ9F June   2016  – November 2024 UCC21520

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Description (continued)
  6. 5 Pin Configuration 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  Power Ratings
    6. 6.6  Insulation Specifications
    7. 6.7  Safety Limiting Values
    8. 6.8  Electrical Characteristics
    9. 6.9  Timing Requirements
    10. 6.10 Switching Characteristics
    11. 6.11 Insulation Characteristics Curves
    12. 6.12 Typical Characteristics
  8. 7 Parameter Measurement Information
    1. 7.1 Propagation Delay and Pulse Width Distortion
    2. 7.2 Rising and Falling Time
    3. 7.3 Input and Disable Response Time
    4. 7.4 Programable Dead Time
    5. 7.5 Power-up UVLO Delay to OUTPUT
    6. 7.6 CMTI Testing
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 VDD, VCCI, and Undervoltage Lock Out (UVLO)
      2. 8.3.2 Input and Output Logic Table
      3. 8.3.3 Input Stage
      4. 8.3.4 Output Stage
      5. 8.3.5 Diode Structure in the UCC21520 and the UCC21520A
    4. 8.4 Device Functional Modes
      1. 8.4.1 Disable Pin
      2. 8.4.2 Programmable Dead-Time (DT) Pin
        1. 8.4.2.1 Tying the DT Pin to VCC
        2. 8.4.2.2 DT Pin Connected to a Programming Resistor Between DT and GND Pins
  10. 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 Designing INA/INB Input Filter
        2. 9.2.2.2 Select External Bootstrap Diode and its Series Resistor
        3. 9.2.2.3 Gate Driver Output Resistor
        4. 9.2.2.4 Gate to Source Resistor Selection
        5. 9.2.2.5 Estimate Gate Driver Power Loss
        6. 9.2.2.6 Estimating Junction Temperature
        7. 9.2.2.7 Selecting VCCI, VDDA/B Capacitor
          1. 9.2.2.7.1 Selecting a VCCI Capacitor
          2. 9.2.2.7.2 Selecting a VDDA (Bootstrap) Capacitor
          3. 9.2.2.7.3 Select a VDDB Capacitor
        8. 9.2.2.8 Dead Time Setting Guidelines
        9. 9.2.2.9 Application Circuits with Output Stage Negative Bias
      3. 9.2.3 Application Curves
  11. 10Power Supply Recommendations
  12. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  13. 12Device and Documentation Support
    1. 12.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Certifications
    4. 12.4 Receiving Notification of Documentation Updates
    5. 12.5 Support Resources
    6. 12.6 Trademarks
    7. 12.7 Electrostatic Discharge Caution
    8. 12.8 Glossary
  14. 13Revision History
  15. 14Mechanical, Packaging, and Orderable Information

8.3.3 Input Stage

The input pins (INA, INB, and DIS) of the UCC21520 and the UCC21520A are based on a TTL and CMOS compatible input-threshold logic that is totally isolated from the VDD supply voltage. The input pins are easy to drive with logic-level control signals (such as those from 3.3-V micro-controllers), since the UCC21520 and the UCC21520A have a typical high threshold (VINAH) of 1.8 V and a typical low threshold of 1 V, which vary little with temperature (see Figure 6-22, Figure 6-23). A wide hysterisis (VINA_HYS) of 0.8 V makes for good noise immunity and stable operation. If any of the inputs are ever left open, internal pull-down resistors force the pin low. These resistors are typically 200 kΩ (see Section 8.2). However, it is still recommended to ground an input if it is not being used.

Since the input side of the UCC21520 and the UCC21520A is isolated from the output drivers, the input signal amplitude can be larger or smaller than VDD, provided that it doesn’t exceed the recommended limit. This allows greater flexibility when integrating with control signal sources, and allows the user to choose the most efficient VDD for their chosen gate. That said, the amplitude of any signal applied to INA or INB must never be at a voltage higher than VCCI.