SNVS629F May   2011  – December 2019 LM5050-1 , LM5050-1-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Full Application
      2.      Typical Redundant Supply Configuration
  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: LM5050-1
    3. 6.3 ESD Ratings: LM5050-1-Q1
    4. 6.4 Recommended Operating Conditions
    5. 6.5 Thermal Information
    6. 6.6 Electrical Characteristics
    7. 6.7 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 IN, GATE, and OUT Pins
      2. 7.3.2 VS Pin
      3. 7.3.3 OFF Pin
    4. 7.4 Device Functional Modes
      1. 7.4.1 ON/OFF Control Mode
      2. 7.4.2 External Power Supply Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 MOSFET Selection
      2. 8.1.2 Short Circuit Failure of an Input Supply
    2. 8.2 Typical Applications
      1. 8.2.1 Typical Application With Input and Output Transient Protection
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Power Supply Components (R1 C1,) Selection
          2. 8.2.1.2.2 MOSFET (Q1) Selection
          3. 8.2.1.2.3 D1 and D2 Selection for Inductive Kick-Back Protection
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Using a Separate VS Supply for Low Vin Operation
      3. 8.2.3 ORing of Two Power Sources
      4. 8.2.4 Reverse Input Voltage Protection With IQ Reduction
      5. 8.2.5 Basic Application With Input Transient Protection
      6. 8.2.6 48-V Application With Reverse Input Voltage (VIN = –48 V) Protection
        1. 8.2.6.1 Application Curves
  9. 9 Power Supply Recommendations
  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 Related Links
    3. 11.3 Community 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

7.1 Overview

Blocking diodes are commonly placed in series with supply inputs for the purpose of ORing redundant power sources and protecting against supply reversal. The LM5050 replaces diodes in these applications with an N-MOSFET to reduce both the voltage drop and power loss associated with a passive solution. At low input voltages, the improvement in forward voltage loss is readily appreciated where headroom is tight, as shown in Figure 2. The LM5050 operates from 5 V to 75 V and it can withstand an absolute maximum of 100 V without damage. A 12-V or 15-A ideal diode application is shown in Figure 24. Several external components are included in addition to the MOSFET, Q1. Ideal diodes, like their non-ideal counterparts, exhibit a behavior known as reverse recovery. In combination with parasitic or intentionally introduced inductances, reverse recovery spikes may be generated by an ideal diode during an reverse current shutdown. D1, D2 and R1 protect against these spikes which might otherwise exceed the LM5050 100-V survival rating. COUT also plays a role in absorbing reverse recovery energy. Spikes and protection schemes are discussed in detail in the Short Circuit Failure of an Input Supply section.

NOTE

The OFF pin may be used to active the GATE pull down circuit and turn off the pass MOSFET, but it does not disconnect the load from the input because Q1’s body diode is still present.

If Vs is powered while IN is floating or grounded, then about 0.5mA will leak from the Vs pin into the IC and about 3mA will leak from the OUT pin into the IC. From this leakage, about 50 uA will flow out of the IN pin and the rest will flow to ground. This does not affect long term reliability of the IC, but may influence circuit design. See Reverse Input Voltage Protection With IQ Reduction for details on how to avoid this leakage current.