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
MAX5943: Typical Operating Circuit
Applications/Uses
  • FireWire® Desktop/Notebook Port
  • FireWire® Hub
  • FireWire® Peripheral Device Current Limit
  • Hot Swap
DataSheet
titleDownload file
MAX5943 Data SheetMAX5943.pdf
Parametrics
Part NumberVIN
(V)
VIN
(V)
Circuit Breaker/ Current LimitCircuit Breaker/Current Limit Threshold
(mV)
Fault Condition ControlChannelsPositive/Negative RailFeaturesPackage/PinsBudgetary
Price
minmaxSee Notes
MAX59437.537Circuit Breaker
Current Limit
AdjustableLatched Off
Periodic Retry
1PositiveSingle Firewire ControllerQSOP/16$1.97 @1k

Part NumberReverse Current Protect.Under Voltage ProtectCharge Pump Cap.Soft StartEnableFault IndicatorPackage/PinsOper. Temp.
(°C)
Budgetary
Price
See Notes
MAX5943YesYesNoYesYesYesQSOP/16-40 to +85$1.97 @1k
Design kits & evaluation modules
Quality and Environmental Data
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX5943AEEENo Longer AvailableMAX5943AEEE+QSOP,;16 pin;30.9 mm²-40°C to +85°CNo
MAX5943AEEE+ActiveQSOP,;16 pin;30.9 mm²-40°C to +85°CLead Free
MAX5943AEEE+TActiveQSOP,;16 pin;30.9 mm²-40°C to +85°CLead Free
MAX5943AEEE-TNo Longer AvailableMAX5943AEEE+TQSOP;16 pin-40°C to +85°CSee data sheet
MAX5943BEEENo Longer AvailableMAX5943BEEE+QSOP,;16 pin;30.9 mm²-40°C to +85°CNo
MAX5943BEEE+ActiveQSOP,;16 pin;30.9 mm²-40°C to +85°CLead Free
MAX5943BEEE+TNo Longer AvailableQSOP;16 pin-40°C to +85°CSee data sheet
MAX5943BEEE-TNo Longer AvailableQSOP;16 pin-40°C to +85°CSee data sheet
MAX5943CEEENo Longer AvailableMAX5943CEEE+QSOP,;16 pin;30.9 mm²-40°C to +85°CNo
MAX5943CEEE+ActiveQSOP,;16 pin;30.9 mm²-40°C to +85°CLead Free
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX5943CEEE+TNo Longer AvailableQSOP;16 pin-40°C to +85°CSee data sheet
MAX5943CEEE-TNo Longer AvailableQSOP;16 pin-40°C to +85°CSee data sheet
MAX5943DEEENo Longer AvailableMAX5943DEEE+QSOP,;16 pin;30.9 mm²-40°C to +85°CNo
MAX5943DEEE+ActiveQSOP,;16 pin;30.9 mm²-40°C to +85°CLead Free
MAX5943DEEE+TNo Longer AvailableQSOP;16 pin-40°C to +85°CSee data sheet
MAX5943DEEE-TNo Longer AvailableQSOP;16 pin-40°C to +85°CSee data sheet
MAX5943EEEENo Longer AvailableMAX5943EEEE+QSOP,;16 pin;30.9 mm²-40°C to +85°CNo
MAX5943EEEE+ActiveQSOP,;16 pin;30.9 mm²-40°C to +85°CLead Free
MAX5943EEEE+TNo Longer AvailableQSOP;16 pin-40°C to +85°CSee data sheet
MAX5943EEEE-TNo Longer AvailableQSOP;16 pin-40°C to +85°CSee data sheet
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