MAX5944

RECOMMENDED FOR NEW DESIGNS

Dual FireWire Current Limiter and Low-Drop ORing Switch Controller

Data Sheet (Rev. 2) Product Selection Table
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Overview

  • Provides Safe Hot-Swap for 7.5V to 37V Power Supplies
  • Dual-Channel Hot-Swap
  • Low-Drop Power ORing with Ultra-Fast Turn-Off
  • Active Current Limit
  • ±5% Current-Limit Sensing Accuracy
  • 2ms Current-Limit Timeout
  • Fast Current-Limit Response to Output Short-Circuit Conditions
  • Drives External n-Channel Power MOSFETs
  • Independent Overcurrent Fault Status Outputs
  • 259ms Autoretry Period
  • 10µA (Per Channel) Shutdown Current
  • Independent ON/OFF Control Allows Undervoltage Lockout Programming
  • Fast Load Disconnect Control Through ON/OFF Inputs
  • Bidirectional Load Disconnect
  • Power Routing from One Port to Another

The MAX5944 is a dual, current limiter/low-drop ORing, switch controller power-management IC for FireWire® applications. Each independent channel controls two external power MOSFETs to regulate current from the input power supply to the load and performs low-voltagedrop power-supply ORing. The MAX5944 operates over the 7.5V to 37V input range and provides inrush and output current limit in addition to diode ORing functions suitable for FireWire applications.

The MAX5944 allows the safe insertion and removal of FireWire peripherals into a live FireWire port by providing inrush current control and output current-limiting functions. The MAX5944 features a current-limit function that actively limits the current drawn by the load with a 2ms timeout. Its autoretry function then automatically restarts after the 259ms autoretry delay time.

The ORing feature provides a very efficient way to protect the FireWire port when connected to another FireWire peripheral that sources a higher voltage. By turning off the external MOSFETS, the MAX5944 provides a true bidirectional load disconnect. Each channel has an independent ON/OFF control that results in less than 10µA supply current per channel.

The MAX5944 operates over the -40°C to +125°C extended temperature range and is available in a 16-pin SO package.

Applications

  • FireWire® Desktop/Notebook Port
  • FireWire® Hub
  • FireWire® Peripheral Device Current Limit
  • Hot Swap
MAX5944
Dual FireWire Current Limiter and Low-Drop ORing Switch Controller
MAX5944: Typical Operating Circuit
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Documentation

Data Sheet 1

Reliability Data 1

Design Note 1

Technical Articles 2

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Software Resources

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Hardware Ecosystem

Parts Product Life Cycle Description
Protection Switches & Controllers 3
MAX5943
PRODUCTION FireWire Current Limiter and Low-Drop ORing Switch Controller
MAX5902
PRODUCTION +72V SOT23/TDFN Simple Swapper Hot-Swap Controllers
MAX4271
PRODUCTION 3V to 12V, Current-Limiting, Hot Swap Controllers with Autoretry, DualSpeed/BiLevel Fault Protection
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Evaluation Kits

MAX5944EVKIT

Evaluation Kit for the MAX5944

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Features and Benefits

  • Safely Hot-Swaps 7.5V to 37V FireWire Power Supplies
  • Demonstrates Two-Channel Hot-Swap
  • Current Limit Configured for 1.6A per Channel
  • Low-Voltage-Drop Power ORing
  • Demonstrates Active Current-Limit Feature
  • Programmable Load Current Limit
  • 2ms Regulated Current-Limit Timeout
  • Autoretry Fault Management
  • Configurable Undervoltage Lockout
  • Overcurrent Active-Low FAULTA and Active-Low FAULTB Output Status Indicators
  • Surface-Mount Construction
  • Fully Assembled and Tested

Product Details

The MAX5944 evaluation kit (EV kit) circuit demonstrates the multiple functions of the MAX5944 IC. The MAX5944 IC is a two-channel controller that performs hot-swapping, power-supply ORing, and current-limiting functions for FireWire® applications. The MAX5944 controls n-channel MOSFETs to regulate load current from two input power supplies and performs low-voltage-drop power-supply ORing. The output current limit and input undervoltage-lockout thresholds are configurable.

The MAX5944 EV kit is intended for 7.5V to 37V FireWire power-supply applications. The current-limit threshold is configured to 1.6A per channel. Shutdown mode can be controlled with an on-board jumper. A fault output for each channel is provided for circuit monitoring.

Applications

  • FireWire® Desktop/Notebook Port
  • FireWire® Hub
  • FireWire® Peripheral Device Current Limit
  • Hot Swap
MAX5944EVKIT
Evaluation Kit for the MAX5944

Latest Discussions

1 Years Ago
Need to Merge 2 power supplies to 1
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