SNOSD08A September   2015  – October  2015 LM74670-Q1

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 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 During T0
      2. 7.3.2 During T1
      3. 7.3.3 Pin Operation
        1. 7.3.3.1 Anode and Cathode Pins
        2. 7.3.3.2 VcapH and VcapL Pins
        3. 7.3.3.3 Gate Drive Pin
        4. 7.3.3.4 Gate Pull Down Pin
    4. 7.4 Device Functional Modes
      1. 7.4.1 Duty Cycle Calculation
      2. 7.4.2 Startup Voltage
  8. 8 Application and Implementation
    1. 8.1 Typical Rectifier Application
      1. 8.1.1 Design Requirements
      2. 8.1.2 Detailed Design Procedure
        1. 8.1.2.1 Design Considerations
        2. 8.1.2.2 Capacitor Selection
        3. 8.1.2.3 MOSFET Selection
      3. 8.1.3 Application Curves
    2. 8.2 Design Requirements
  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 Community Resources
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information
  13. 14Mechanical, Packaging, and Orderable Information

Package Options

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

1 Features

  • AEC-Q100 Qualified With the Following Results:
    • Device Temperature Grade 1: –40°C to +125°C Ambient Operating Temperature Range
    • Exceeds HBM ESD Classification Level 2
    • Device CDM ESD Classification Level C4B
  • Peak Input AC Voltage: 42 V
  • Zero IQ
  • Charge Pump Gate Driver for external N-Channel MOSFET
  • Low Forward-Voltage Drop and Less Power Dissipation Compared to Schottky Diode
  • Capable of handling AC signal up to 300-Hz Frequency

2 Applications

  • AC Rectifier
  • Alternator
  • Power Tools
  • Reverse Polarity Protection
     

3 Description

The LM74670-Q1 is a controller device that can be used with an N-Channel MOSFET in full or half bridge rectifier architectures for alternators. It is designed to drive an external MOSFET to emulate an ideal diode. A unique advantage of this scheme is that it is not ground referenced, thus it has zero IQ. The schottky diodes in full or half bridge rectifiers and alternators can be replaced with the LM74670-Q1 solution to avoid forward conduction diode losses and produce more efficient AC-DC converters.

The LM74670-Q1 controller provides a gate drive for external N-Channel MOSFET and a fast response internal comparator to pull-down the MOSFET Gate in the event of reverse polarity. This device can support an AC signal frequency up to 300Hz.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
LM74670-Q1 VSSOP (8) 3.00 mm × 5.00 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

   
 Smart Diode Configuration

LM74670-Q1 simplified_schematic_snosd08.gif

Smart Diode Full Bridge Rectifier Application

LM74670-Q1 rectifier_application_snosd08.gif