MAX5943

Provides Safe Hot Swap for 7.5V to 37V Power Supplies
Low-Drop Power ORing with Ultra-Fast Turn-Off
Programmable Active Current Limit (MAX5943A)
Programmable Circuit Breaker (MAX5943BMAX5943E)
±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
10A Shutdown Current
ON/OFF Control Allows Undervoltage Lockout Programming
Fast Load Disconnect Control Through ON Input

(Voltages referenced to GND, unless otherwise noted.)
IN ............................................................................-0.3V to +80V
OUT .........................................................................-0.3V to +80V
SENSE to IN................................................................-1V to +0.3V
GATE1 to SENSE..........................................................-0.3V to +8V
GATE2 to OUT (internally clamped)..............................-0.3V to +8V
FAULT........................................................................-0.3V to +85V
ON, TIM, ILIM, LATCH, OR_ADJ, ONQ1 ..........-....0.3V to (IN + 0.3V)
Continuous Power Dissipation (TA = +70°C)
16-Pin QSOP (derate 8.3mW/°C above +70°C)................667mW
Operating Temperature Range ............................-40°C to +85°C
Maximum Junction Temperature ........................................+150°C
Storage Temperature Range ..............................-60°C to +150°C
ESD Rating (Human Body Model).............................................2000V
Lead Temperature (soldering, 10s) .....................................+300°C

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 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 10A 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 MAX5943BMAX5943E do not actively limit the load current but provide a circuit-breaker function. See the Selector Guide 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.