SLUSET9E December   2022  – January 2024 UCC21551-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings (Automotive)
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Power Ratings
    6. 5.6  Insulation Specifications
    7. 5.7  Safety Limiting Values
    8. 5.8  Electrical Characteristics
    9. 5.9  Switching Characteristics
    10. 5.10 Insulation Characteristics Curves
    11. 5.11 Typical Characteristics
  7. 6 Parameter Measurement Information
    1. 6.1 Propagation Delay and Pulse Width Distortion
    2. 6.2 Rising and Falling Time
    3. 6.3 Input and Disable Response Time
    4. 6.4 Programmable Dead Time
    5. 6.5 Power-up UVLO Delay to OUTPUT
    6. 6.6 CMTI Testing
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 VDD, VCCI, and Undervoltage Lock Out (UVLO)
      2. 7.3.2 Input and Output Logic Table
      3. 7.3.3 Input Stage
      4. 7.3.4 Output Stage
      5. 7.3.5 Diode Structure in the UCC21551x-Q1
    4. 7.4 Device Functional Modes
      1. 7.4.1 Enable Pin
      2. 7.4.2 Programmable Dead-Time (DT) Pin
        1. 7.4.2.1 Tying the DT Pin to VCC
        2. 7.4.2.2 DT Pin Connected to a Programming Resistor Between DT and GND Pins
  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 Designing INA/INB Input Filter
        2. 8.2.2.2 Select External Bootstrap Diode and its Series Resistor
        3. 8.2.2.3 Gate Driver Output Resistor
        4. 8.2.2.4 Gate to Source Resistor Selection
        5. 8.2.2.5 Estimate Gate Driver Power Loss
        6. 8.2.2.6 Estimating Junction Temperature
        7. 8.2.2.7 Selecting VCCI, VDDA/B Capacitor
          1. 8.2.2.7.1 Selecting a VCCI Capacitor
          2. 8.2.2.7.2 Selecting a VDDA (Bootstrap) Capacitor
          3. 8.2.2.7.3 Select a VDDB Capacitor
        8. 8.2.2.8 Dead Time Setting Guidelines
        9. 8.2.2.9 Application Circuits with Output Stage Negative Bias
      3. 8.2.3 Application Curves
  10. 9 Power Supply Recommendations
  11. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Certifications
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Support Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  13. 12Revision History
  14. 13Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.1 VDD, VCCI, and Undervoltage Lock Out (UVLO)

The UCC21551x-Q1 has an internal undervoltage lock out (UVLO) protection feature on the supply circuit blocks between the VDD and VSS pins for both outputs. When the VDD bias voltage is lower than VVDD_ON at device start-up or lower than VVDD_OFF after start-up, the VDD UVLO feature holds the affected output low, regardless of the status of the input pins (INA and INB).

When the output stages of the driver are in an unbiased or UVLO condition, the driver outputs are held low by an active clamp circuit that limits the voltage rise on the driver outputs (Illustrated in Figure 7-1). In this condition, the upper PMOS is resistively held off by RHi-Z while the lower NMOS gate is tied to the driver output through RCLAMP. In this configuration, the output is effectively clamped to the threshold voltage of the lower NMOS device, typically around 1.5 V, when no bias power is available.

GUID-68A5666D-41BC-42BA-9682-2C3473FB7081-low.gifFigure 7-1 Simplified Representation of Active Pulldown Feature

The VDD UVLO protection has a hysteresis feature (VVDD_HYS). This hysteresis prevents chatter when there is ground noise from the power supply. Also this allows the device to accept small drops in bias voltage, which is bound to happen when the device starts switching and operating current consumption increases suddenly.

The input side of the UCC21551x-Q1 also has an internal undervoltage lock out (UVLO) protection feature. The device isn't active unless the voltage, VCCI, is going to exceed VVCCI_ON on start up. And a signal will cease to be delivered when that pin receives a voltage less than VVCCI_OFF. And, just like the UVLO for VDD, there is hysteresis (VVCCI_HYS) to ensure stable operation.

All versions of the UCC21551x-Q1 can withstand an absolute maximum of 30 V for VDD, and 5.5 V for VCCI.

Table 7-1 UCC21551x-Q1 VCCI UVLO Feature Logic
CONDITION INPUTS OUTPUTS
INA INB OUTA OUTB
VCCI-GND < VVCCI_ON during device start upHLLL
VCCI-GND < VVCCI_ON during device start upLHLL
VCCI-GND < VVCCI_ON during device start upHHLL
VCCI-GND < VVCCI_ON during device start upLLLL
VCCI-GND < VVCCI_OFF after device start upHLLL
VCCI-GND < VVCCI_OFF after device start upLHLL
VCCI-GND < VVCCI_OFF after device start upHHLL
VCCI-GND < VVCCI_OFF after device start upLLLL
Table 7-2 UCC21551x-Q1 VDD UVLO Feature Logic
CONDITION INPUTS OUTPUTS
INA INB OUTA OUTB
VDD-VSS < VVDD_ON during device start upHLLL
VDD-VSS < VVDD_ON during device start upLHLL
VDD-VSS < VVDD_ON during device start upHHLL
VDD-VSS < VVDD_ON during device start upLLLL
VDD-VSS < VVDD_OFF after device start upHLLL
VDD-VSS < VVDD_OFF after device start upLHLL
VDD-VSS < VVDD_OFF after device start upHHLL
VDD-VSS < VVDD_OFF after device start upLLLL