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MAX5943：FireWire Current Limiter and Low-Drop ORing Switch Controller

Industry's First IEEE 1394/FireWire-Compliant Hot-Swap Controllers

The MAX5943 is a fully integrated power-management IC for FireWire® applications. This device controls two external power n-channel MOSFETs to regulate current from the input power supply to the load and performs low-voltage-drop, power-supply ORing. The MAX5943 operates over a 7.5V to 37V input range and provides inrush and output current limit in addition to a diode ORing function suitable for FireWire applications. The MAX5943 FireWire/IEEE 1394™ protective circuit (Figure 12 of the full data sheet) is UL® recognized. The MAX5943 allows the safe insertion and removal of FireWire peripherals into a live FireWire port by providing inrush current control and an output current-limiting function. 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 both external MOSFETS, the MAX5943 provides a true bidirectional load disconnect. A low-current shutdown mode disables the MAX5943, resulting in less than 10µA supply current. A pin-selectable input allows latched or autoretry fault management after a fault. The MAX5943A features a current-limit function that actively limits the current drawn by the load with a programmable timeout. The MAX5943B–MAX5943E do not actively limit the load current but provide a circuit-breaker function. See the Selector Guide in the full data sheet for the default and programmable circuit-breaker timeouts. The MAX5943 operates over the -40°C to +85°C extended temperature range and is available in a 16-pin QSOP package.

Key Features Provides Safe Hot Swap for 7.5V to 37V Power Supplies UL-Recognized FireWire/IEEE 1394 Protective Circuit Low-Drop Power ORing with Ultra-Fast Turn-Off Programmable Active Current Limit (MAX5943A) Programmable Circuit Breaker (MAX5943B–MAX5943E) ±5% Current-Limit Sensing Accuracy Programmable Current-Limit/Circuit-Breaker Timeout Fast Current-Limit Response to Output Short-Circuit Conditions (MAX5943A) Drives External n-Channel Power MOSFETs Overcurrent Fault Status Output Latched or Autoretry Overcurrent Fault Management 10µA Shutdown Current ON/OFF Control Allows Undervoltage Lockout Programming Fast Load Disconnect Control Through ON Input

MAX5943: Typical Operating Circuit Applications/Uses FireWire® Desktop/Notebook Port FireWire® Hub FireWire® Peripheral Device Current Limit Hot Swap

DataSheet

Parametrics

Design kits & evaluation modules

• MAX5943AEVKIT

Quality and Environmental Data

• MAX5943.pdf

Ordering Information