SNVS628H October   2009  – December 2019 LM5060

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Circuit
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
    4. 7.4 Device Functional Modes
      1. 7.4.1 Power-Up Sequence
      2. 7.4.2 Status Conditions
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1  Gate Control
      2. 8.1.2  Fault Timer
      3. 8.1.3  VGS Considerations
      4. 8.1.4  VDS Fault Condition
      5. 8.1.5  Overcurrent Fault
      6. 8.1.6  Restart After Overcurrent Fault Event
      7. 8.1.7  Enable
      8. 8.1.8  UVLO
      9. 8.1.9  OVP
      10. 8.1.10 Restart After OVP Event
      11. 8.1.11 nPGD Pin
    2. 8.2 Typical Applications
      1. 8.2.1 Example Number 1: LM5060EVAL Design
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 VDS Fault Detection and Selecting Sense Pin Resistor RS
          2. 8.2.1.2.2 Turn-On Time
          3. 8.2.1.2.3 Fault Detection Delay Time
          4. 8.2.1.2.4 MOSFET Selection
          5. 8.2.1.2.5 Input and Output Capacitors
          6. 8.2.1.2.6 UVLO, OVP
          7. 8.2.1.2.7 POWER GOOD Indicator
          8. 8.2.1.2.8 Input Bypass Capacitor
          9. 8.2.1.2.9 Large Load Capacitance
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Example Number 2: Reverse Polarity Protection With Diodes
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Application Curve
      3. 8.2.3 Example Number 3: Reverse Polarity Protection With Resistor
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
          1. 8.2.3.2.1 Reverse Polarity Protection With a Resistor
          2. 8.2.3.2.2 Fault Detection With RS and RO
        3. 8.2.3.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.1.2.6 UVLO, OVP

The UVLO and OVP thresholds are programmed to enable the external MOSFET (Q1) when the input supply voltage is within the desired operating range. If the supply voltage is low enough that the voltage at the UVLO pin is below the UVLO threshold, Q1 is switched off by a 2.2 mA (typical) current sink at the GATE pin, denying power to the load. The UVLO threshold has approximately 180 mV of hysteresis.

If the supply voltage is high enough that the voltage at the OVP pin is above the OVP threshold, the GATE pin is pulled low with a 80 mA current sink. Hysteresis is provided for each threshold. The OVP threshold has approximately 240 mV of hysteresis.

Option A: The configuration shown in Figure 29 requires three resistors (R1, R2, and R3) to set the thresholds.

LM5060 30104231.gifFigure 29. UVLO and OVP Thresholds Set by R1, R2 and R3

The procedure to calculate the resistor values is as follows:

  1. Select R1 based on current consumption allowed in the resistor divider, including UVLOBIAS, and consideration of noise sensitivity. A value less than 100 kΩ is recommended, with lower values providing improved immunity to variations in ULVOBIAS.
  2. Calculate R3 with the following formula:
    3. Equation 9. LM5060 30104232.gif
  3. Calculate R2 with the following formula:
    4. Equation 10. LM5060 30104233.gif

VINMIN is the minimum and VINMAX is the maximum input voltage of the design specification. All other variables can be found in the Electrical Characteristics table of this document. To calculate the UVLO lower threshold including its hysteresis for falling VIN, use (UVLOTH-UVLOHYS) instead of UVLOTH in the formulas above. To calculate the OVP lower threshold including hysteresis for falling VIN, use (OVPTH-OVPHYS) instead of OVPTH. With three given resistors R1, R2, and R3, the thresholds can be calculated with the formulas below:

Equation 11. LM5060 30104234.gif

Also in these two formulas, the respective lower threshold value including the hysteresis is calculated by using (UVLOTH-UVLOHYS) instead of UVLOTH, and (OVPTH-OVPHYS) instead of OVPTH. The worst case thresholds, over the operating temperature range, can be calculated using the respective min and max values in bold font in the Electrical Characteristics.

Option B: UVLO and OVP can be independently adjusted using two resistor dividers as shown in Figure 30.

LM5060 30104235.gifFigure 30. Programming the Thresholds with Resistors R8-R11

Choose the upper UVLO thresholds to ensure operation down to the lowest required operating input voltage (VINMIN). Select R11 based on resistive divider current consumption and noise sensitivity. A value less than 100 kΩ is recommended, with lower values providing improved immunity to variations in ULVOBIAS.

Equation 12. LM5060 30104236.gif

To calculate the UVLO low threshold including its hysteresis, use (UVLOTH-UVLOHYS) instead of UVLOTH in the formula above. Choose the lower OVP threshold to ensure operation up to the highest VIN voltage required (VINMAX). Select R9 based on resistive divider current consumption A value less than 100 kΩ is recommended.

Equation 13. LM5060 30104237.gif

To calculate the OVP low threshold including hysteresis, use (OVPTH-OVPHYS) instead of OVPTH. Where the R9-R11 resistor values are known, the threshold voltages are calculated from the following:

Equation 14. LM5060 30104238.gif

Also in these two formulas, the respective low value including the threshold hysteresis is calculated by using (UVLOTH-UVLOHYS) instead of UVLOTH and (OVPTH-OVPHYS) instead of OVPTH. The worst case thresholds, over the operating temperature range, can be calculated using the respective minimum and maximum values in bold font in the Electrical Characteristics.

Option C: The OVP function can be disabled by grounding the OVP pin. The UVLO thresholds are set as described in Figure 30.