SNVSCT1 October   2025 LM5066H

ADVANCE INFORMATION  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  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
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Current Limit
      2. 7.3.2  Foldback Current Limit
      3. 7.3.3  Soft Start Disconnect (SFT_STRT)
      4. 7.3.4  Circuit Breaker
      5. 7.3.5  Power Limit
      6. 7.3.6  UVLO
      7. 7.3.7  OVLO
      8. 7.3.8  Power Good
      9. 7.3.9  VDD Sub-Regulator
      10. 7.3.10 Remote Temperature Sensing
      11. 7.3.11 Damaged MOSFET Detection
      12. 7.3.12 Analog Current Monitor (IMON)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Power Up Sequence
      2. 7.4.2 Gate Control
      3. 7.4.3 Fault Timer and Restart
      4. 7.4.4 Shutdown Control
      5. 7.4.5 Enabling/Disabling and Resetting
    5. 7.5 Programming
      1. 7.5.1 PMBus Command Support
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 54V, 100A PMBus Hot Swap Design
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design-In Procedure
          1. 8.2.1.2.1 Selecting the Hotswap FETs
          2. 8.2.1.2.2 dv/dt-Based Start-Up
            1. 8.2.1.2.2.1 Choosing the VOUT Slew Rate
          3. 8.2.1.2.3 Select RSNS and CL Setting
          4. 8.2.1.2.4 Select Power Limit
          5. 8.2.1.2.5 Set Fault Timer
          6. 8.2.1.2.6 Check MOSFET SOA
          7. 8.2.1.2.7 Set UVLO and OVLO Thresholds
            1. 8.2.1.2.7.1 Option A
            2. 8.2.1.2.7.2 Option B
            3. 8.2.1.2.7.3 Option C
            4. 8.2.1.2.7.4 Option D
          8. 8.2.1.2.8 Power Good Pin
          9. 8.2.1.2.9 Input and Output Protection
        3. 8.2.1.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Third-Party Products Disclaimer
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Package Option Addendum
    2. 11.2 Tape and Reel Information
    3. 11.3 Mechanical Data

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • PWP|28
Thermal pad, mechanical data (Package|Pins)
8.2.1.2.3 Select RSNS and CL Setting

LM5066H1 can be used with a VCL of 25 or 50mV using CL pin configurations (Connect CL pin to GND to set the nominal overcurrent threshold at 50mV. Connecting CL to VDD sets the overcurrent threshold to be 25mV). Using the DEVICE_SETUP2 (EFh, Read/Write Word) register, the current limit can be set at 10mV, 12.5mV, 15mV, 17.5mV, 20mV, and 22.5mV. TI recommends targeting a current limit that is at least 10% above the maximum load current to account for the tolerance of the LM5066H1 current limit. Targeting a current limit of 110A, the sense resistor can be computed as follows:

Equation 7. RSNS,CLC=VCLILIM=25mV110A=227μΩ

Typically, sense resistors are only available in discrete values. If a precise current limit is desired, a sense resistor along with a resistor divider can be used as shown in Figure 8-2.

LM5066H SENSE Resistor DividerFigure 8-2 SENSE Resistor Divider

The next larger available sense resistor should be chosen (250µΩ in this case). The ratio of R1 and R2 can be computed as follows:

Equation 8. R1R2=RSNS,CLCRSNS-RSNS,CLC=227250-227=9.9

Note that the SENSE pin pulls 25μA of current, which creates an offset across R2. TI recommends keeping R2 below 10Ω to reduce the offset that this introduces. In addition, the 1% resistors add to the current monitoring error. Finally, if the resistor divider approach is used, the user should compute the effective sense resistance (RSNS,EFF) using Equation 9 and use that in all equations instead of RSNS.

Equation 9. LM5066H

R1 is selected as 10Ω, R2 becomes 1.01Ω. Closest selected value of R2 is 1Ω.

Note that for many applications, a precise current limit may not be required. In that case, it is simpler to pick the next smaller available sense resistor.