SNOSDC0A October   2020  – December 2020 LM7310

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Timing Requirements
    7. 6.7 Switching Characteristics
    8.     14
    9. 6.8 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Input Reverse Polarity Protection
      2. 7.3.2 Undervoltage Protection (UVLO & UVP)
      3. 7.3.3 Overvoltage Lockout (OVLO)
      4. 7.3.4 Inrush Current control and Fast-trip
        1. 7.3.4.1 Slew Rate (dVdt) and Inrush Current Control
        2. 7.3.4.2 Fast-Trip During Steady State
      5. 7.3.5 Analog Load Current Monitor Output
      6. 7.3.6 Reverse Current Protection
      7. 7.3.7 Overtemperature Protection (OTP)
      8. 7.3.8 Fault Response
      9. 7.3.9 Power Good Indication (PG)
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Single Device, Self-Controlled
      1. 8.2.1 Typical Application
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Setting Undervoltage and Overvoltage Thresholds
          2. 8.2.1.2.2 Setting Output Voltage Rise Time (tR)
          3. 8.2.1.2.3 Setting Power Good Assertion Threshold
          4. 8.2.1.2.4 Setting Analog Current Monitor Voltage (IMON) Range
        3. 8.2.1.3 Application Curves
    3. 8.3 Active ORing
    4. 8.4 Priority Power MUXing
    5. 8.5 USB PD Port Protection
    6. 8.6 Parallel Operation
  9. 9 Power Supply Recommendations
    1. 9.1 Transient Protection
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    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
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.9 Power Good Indication (PG)

The LM73100 provides an active high digital output (PG) which serves as a power good indication signal and is asserted high depending on the voltage at the PGTH pin along with the device state information. The PG is an open-drain pin and needs to be pulled up to an external supply.

After power up, PG is pulled low initially. The device initiates a inrush sequence in which the HFET is turned on in a controlled manner. When the HFET gate voltage reaches the full overdrive indicating that the inrush sequence is complete and the voltage at PGTH is above VPGTH(R), the PG is asserted after a de-glitch time (tPGA).

PG is de-asserted if at any time during normal operation, the voltage at PGTH falls below VPGTH(F), or the device detects a fault. The PG de-assertion de-glitch time is tPGD.

GUID-20200920-CA0I-0BPC-2VXB-7VLRRNMWDCTT-low.gif Figure 7-10 LM73100 PG Timing Diagram
Table 7-3 LM73100 PG Indication Summary

Event

Protection Response

PG Pin

PG Delay

Undervoltage (UVP or UVLO)

Shutdown

L

Input Reverse Polarity

Shutdown

L

Overvoltage (OVLO)

Shutdown

L

tPGD

Steady State

N/A

H (If PGTH pin voltage > VPGTH(R))

L (If PGTH pin voltage < VPGTH(F))

tPGA

tPGD

Transient overcurrent during steady state

Fast-trip

H (If PGTH pin voltage > VPGTH(R))

L (If PGTH pin voltage < VPGTH(F))

tPGA

tPGD

Reverse current ((VOUT - VIN) > VREVTH)

Reverse current blocking

L

tPGD

Overtemperature

Shutdown

L

tPGD

When there is no supply to the device, the PG pin is expected to stay low. However, there is no active pull-down in this condition to drive this pin all the way down to 0 V. If the PG pin is pulled up to an independent supply which is present even if the device is unpowered, there can be a small voltage seen on this pin depending on the pin sink current, which is a function of the pull-up supply voltage and resistor. Minimize the sink current to keep this pin voltage low enough not to be detected as a logic HIGH by associated external circuits in this condition.