SLUSAQ3H November   2011  – June 2024 UCC27523 , UCC27525 , UCC27526

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 Electrical Characteristics
    6. 6.6 Switching Characteristics
    7. 6.7 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 VDD and Undervoltage Lockout
      2. 7.3.2 Operating Supply Current
      3. 7.3.3 Input Stage
      4. 7.3.4 Enable Function
      5. 7.3.5 Output Stage
      6. 7.3.6 Low Propagation Delays and Tightly Matched Outputs
    4. 7.4 Device Functional Modes
  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
        1. 8.2.2.1 Input-to-Output Logic
        2. 8.2.2.2 Enable and Disable Function
        3. 8.2.2.3 VDD Bias Supply Voltage
        4. 8.2.2.4 Propagation Delay
        5. 8.2.2.5 Drive Current and Power Dissipation
      3. 8.2.3 Application Curves
  10. 9 Power Supply Recommendations
  11. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
  12. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  13. 12Revision History
  14. 13Mechanical, Packaging, and Orderable Information

7.3.1 VDD and Undervoltage Lockout

The UCC2752x devices have internal undervoltage-lockout (UVLO) protection feature on the VDD pin supply circuit blocks. When VDD is rising and the level is still below UVLO threshold, this circuit holds the output LOW, regardless of the status of the inputs. The UVLO is typically 4.2 V with 300-mV typical hysteresis. This hysteresis prevents chatter when low VDD supply voltages have noise from the power supply and also when there are droops in the VDD bias voltage when the system commences switching and there is a sudden increase in IDD. The capability to operate at low voltage levels such as below 5 V, along with best-in-class switching characteristics, is especially suited for driving emerging GaN power semiconductor devices.

For example, at power up, the UCC2752x driver-device output remains LOW until the VDD voltage reaches the UVLO threshold if Enable pin is active or floating. The magnitude of the OUT signal rises with VDD until steady-state VDD is reached. The non-inverting operation in Table 3-1 shows that the output remains LOW until the UVLO threshold is reached, and then the output is in-phase with the input. The inverting operation in Figure 7-5 shows that the output remains LOW until the UVLO threshold is reached, and then the output is out-phase with the input. With UCC27526 the output turns to high-state only if INX+ is high and INX– is low after the UVLO threshold is reached.

Because the device draws current from the VDD pin to bias all internal circuits, for the best high-speed circuit performance, TI recommends two VDD bypass capacitors to prevent noise problems. TI highly recommends using surface-mount components. A 0.1-μF ceramic capacitor must be located as close as possible to the VDD to GND pins of the gate-driver device. In addition, a larger capacitor (such as 1-μF) with relatively low ESR must be connected in parallel and close proximity, in order to help deliver the high-current peaks required by the load. The parallel combination of capacitors presents a low impedance characteristic for the expected current levels and switching frequencies in the application.

UCC27523 UCC27525 UCC27526 Power up Non-Inverting DriverFigure 7-4 Power up Non-Inverting Driver
UCC27523 UCC27525 UCC27526 Power up Inverting DriverFigure 7-5 Power up Inverting Driver