SOA Sharing Hot Swap Controller Enables Telecom/Datacom Kilowatt Board Designs

Nov 16 2018 -Norwood, MA
  • LTC4284Analog Devices announces the Power by Linear LTC4284, an energy monitoring hot swap controller with dual MOSFET drive to ease kilowatt level board designs in −48V telecom and datacom systems. The LTC4284 ensures safe board insertion and removal from live backplanes by controlling external N-channel MOSFETs to gently power up load capacitors, preventing sparks, connector damage, and system glitches. High current hot-pluggable boards utilize parallel MOSFETs to reduce voltage drop, but all these MOSFETs require large safe operating area (SOA) to ride through overcurrent faults. By controlling two matching current limited paths, the LTC4284 divides each path’s SOA requirements, reducing MOSFET costs in high current applications (>20A). Further cost savings are afforded with a staged start configuration that employs a low SOA MOSFET in one path and low RDS(ON) MOSFETs in the other path. The LTC4284 provides a rugged solution for hot plugging and monitoring, especially in high power circuit boards for telecom equipment, network routers, and AdvancedTCA systems.

    • View the LTC4284 product page, download the data sheet, order samples and evaluation boards:


    Sitting at the gateway to board power, the LTC4284’s 0.7% accurate 16-bit ADC (analog-to-digital converter), with selectable resolution and speed, reports board voltage, current, power, and energy consumption through an I2C/SMBus digital interface. An additional single-wire broadcast mode can eliminate two opto-isolators. During overcurrent conditions, the LTC4284 folds back its 3.3% accurate current limit for a timeout period that shortens with increasing MOSFET power dissipation. An optional RC network tailors the circuit breaker timer to closely model the MOSFET’s temperature rise, making optimum use of its SOA. Digitally configurable current limit enables dynamic adjustment with load changes and eases selection of low value sense resistors. Minimum and maximum values of the monitored electrical parameters are recorded, with alerts raised when they exceed 8-bit thresholds. Internal EEPROM provides nonvolatile storage for register configuration and fault log data. To prevent catastrophic damage to the board, the MOSFETs are continuously monitored for abnormal conditions such as low gate voltage and drain-to-source short-circuit or large voltage drop.

    Specified over the −40oC to 125oC temperature range, the LTC4284 is offered in a 44-pin 5mm x 8mm QFN package. Device samples and evaluation circuit boards are available online or from your local Analog Devices sales office. For more information, visit

    Summary of Features: LTC4284


    • Enables Safe Board Insertion into Live −48V Backplane
    • 8-Bit to 16-Bit Gear-Shift ADC with Less than 0.7% TUE
    • EEPROM Stores Configuration & Fault Log
    • Digital Interface: I2C/SMBus or Single-Wire Broadcast
    • Floating Topology for Rugged High Voltage Operation
    • High Power Application Features
      • Dual MOSFET Gate Drive & Current Sensing
      • Configurable Parallel, Staged Start, or Single Mode
      • Protects MOSFET with Current Foldback & SOA Time
    • Digital Features
      • Digitally Adjustable 15mV to 30mV Current Limit Sense Voltage with
      • 2% Accuracy & Adjustable Foldback
      • Two ADCs: One for Current & One for Voltage
      • Measures Board Voltage, Current, Power & Energy Use
      • Stores Minimum & Maximum ADC Measurements
      • Alerts When Measurements Exceed Programmed Thresholds
      • Eight General Purpose Input/Outputs
      • Sixteen Auxiliary Voltage ADC Inputs
    • Continuously Monitors MOSFET Health
    • Adjustable Input Undervoltage & Overvoltage Thresholds & Hysteresis
    • Power Good Input & Sequenced Power Good Outputs

    Pricing and Availability
    Product Sample Availability Production Availability Price Each per 1,000 Package
    LTC4284 Now Now Start at $6.95 5mm x 8mm QFN-44
  • About Analog Devices
  • Analog Devices (Nasdaq: ADI) is a leading global high-performance analog technology company dedicated to solving the toughest engineering challenges. We enable our customers to interpret the world around us by intelligently bridging the physical and digital with unmatched technologies that sense, measure, power, connect and interpret. Visit
  • Read and subscribe to Analog Dialogue, ADI's monthly technical journal, at:
  • Editor's Contact Information
Stay Informed