SLUSDP6A may   2019  – july 2023 LM5108

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  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 Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Enable
      2. 7.3.2 Start-up and UVLO
      3. 7.3.3 Input Stages and Interlock Protection
      4. 7.3.4 Level Shifter
      5. 7.3.5 Output Stage
      6. 7.3.6 Negative Voltage Transients
    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 Select Bootstrap and VDD Capacitor
        2. 8.2.2.2 Estimate Driver Power Losses
        3. 8.2.2.3 Selecting External Gate Resistor
        4. 8.2.2.4 Delays and Pulse Width
        5. 8.2.2.5 External Bootstrap Diode
        6. 8.2.2.6 VDD and Input Filter
        7. 8.2.2.7 Transient Protection
      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 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. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.6 Negative Voltage Transients

In most applications, the body diode of the external low-side power MOSFET clamps the HS node to ground. In some situations, board capacitances and inductances can cause the HS node to transiently swing several volts below ground, before the body diode of the external low-side MOSFET clamps this swing. When used in conjunction with the LM5108, the HS node can swing below ground as long as specifications are not violated and conditions mentioned in this section are followed.

HS must always be at a lower potential than HO. Pulling HO more negative than specified conditions can activate parasitic transistors which may result in excessive current flow from the HB supply. This may result in damage to the device. The same relationship is true with LO and VSS. If necessary, a Schottky diode can be placed externally between HO and HS or LO and VSS to protect the device from this type of transient. The diode must be placed as close to the device pins as possible in order to be effective.

Ensure that the HB to HS operating voltage is 16 V or less. Hence, if the HS pin transient voltage is –5 V, then VDD (and thus HB) is ideally limited to 11 V to keep the HB to HS voltage below 16 V. Generally when HS swings negative, HB follows HS instantaneously and therefore the HB to HS voltage does not significantly overshoot.

Low ESR bypass capacitors from HB to HS and from VDD to VSS are essential for proper operation of the gate driver device. The capacitor should be located at the leads of the device to minimize series inductance. The peak currents from LO and HO can be quite large. Any series inductances with the bypass capacitor causes voltage ringing at the leads of the device which must be avoided for reliable operation.