EVALUATION KIT AVAILABLE Click here to ask about the production status of specific part numbers. MAX5944 Dual FireWire Current Limiter and Low-Drop ORing Switch Controller General Description Features The MAX5944 is a dual, current limiter/low-drop ORing, Provides Safe Hot-Swap for 7.5V to 37V Power switch controller power-management IC for FireWire Supplies applications. Each independent channel controls two Dual-Channel Hot-Swap external power MOSFETs to regulate current from the Low-Drop Power ORing with Ultra-Fast Turn-Off input power supply to the load and performs low-voltage- Active Current Limit drop power-supply ORing. The MAX5944 operates over the 7.5V to 37V input range and provides inrush and 5% Current-Limit Sensing Accuracy output current limit in addition to diode ORing functions 2ms Current-Limit Timeout suitable for FireWire applications. Fast Current-Limit Response to Output The MAX5944 allows the safe insertion and removal of Short-Circuit Conditions FireWire peripherals into a live FireWire port by providing Drives External n-Channel Power MOSFETs inrush current control and output current-limiting func- tions. The MAX5944 features a current-limit function that Independent Overcurrent Fault Status Outputs actively limits the current drawn by the load with a 2ms 259ms Autoretry Period timeout. Its autoretry function then automatically restarts 10A (Per Channel) Shutdown Current after the 259ms autoretry delay time. Independent ON/OFF Control Allows The ORing feature provides a very efficient way to protect Undervoltage Lockout Programming the FireWire port when connected to another FireWire peripheral that sources a higher voltage. By turning off Fast Load Disconnect Control Through the external MOSFETS, the MAX5944 provides a true ON/OFF Inputs bidirectional load disconnect. Each channel has an inde- Bidirectional Load Disconnect pendent ON/OFF control that results in less than 10A Power Routing from One Port to Another supply current per channel. The MAX5944 operates over the -40C to +125C Ordering Information extended temperature range and is available in a 16-pin SO package. PART TEMP RANGE PIN-PACKAGE MAX5944ESE -40C to +125C 16 SO Applications FireWire Desktop/Notebook Port Pin Configuration FireWire Peripheral Device Current Limit FireWire Hub Hot Swap TOP VIEW INA 1 16 SENSEA ONA 2 15 GATE1A FAULTA 3 14 GATE2A ONQ1 4 MAX5944 13 OUTA OUTB 5 12 GND GATE2B 6 11 FAULTB 7 10 ONB GATE1B Typical Operating Circuit appears at end of data sheet. SENSEB 8 9 INB FireWire is a registered trademark of Apple Computer, Inc. SO 19-3426 Rev 2 4/21MAX5944 Dual FireWire Current Limiter and Low-Drop ORing Switch Controller Absolute Maximum Ratings (Voltages referenced to GND, unless otherwise noted.) Continuous Power Dissipation (T = +70C) A IN .........................................................................-0.3V to +80V 16-Pin SO (derate 9.1mW/C above +70C) ...............728mW OUT .....................................................................-0.3V to +80V Operating Temperature Range ......................... -40C to +125C SENSE to IN ........................................................-1V to +0.3V Maximum Junction Temperature .....................................+150C GATE1 to SENSE ................................................-0.3V to +8V Storage Temperature Range ............................ -60C to +150C GATE2 to OUT ....................................................-0.3V to +8V ESD Rating (Human Body Model) ....................................2000V FAULT ..................................................................-0.3V to +85V Lead Temperature (soldering, 10s) .................................+300C ON ONQ1 .............................................................-0.3V to +85V Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Electrical Characteristics (V = 7.5V to 37V, GND = 0V, and T = -40C to +85C, unless otherwise noted. Typical values are at V = 12V, T = +25C.) IN A IN A (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS SUPPLIES Supply Voltage Range V 7.5 37 V IN Supply Current I V = 3V, no load, per channel 1.3 2.3 mA IN ON Shutdown Current I V = 0.4V, per channel 5 10 A SD ON IN Default Undervoltage Lockout V V rising, ON = IN 6.2 6.5 6.8 V UVLO IN IN Default Undervoltage- 0.35 V Lockout Hysteresis ON Undervoltage-Lockout V V rising 1.20 1.24 1.275 V ON REF ON Threshold ON Undervoltage-Lockout- 70 mV Threshold Hysteresis ON Input Bias Current I 1 A ON GATE2 (Current-Limit Control) GATE2 Pullup Current (Note 2) I 36 45 54 A G2U 7.5V V 8V 4.25 5.5 6.50 IN GATE2 High Voltage V V - V V G2 GATE2 OUT 8V V 37V 4.5 5.5 6.5 IN Current-Limit Threshold Voltage V V - V 47.5 50 52.5 mV TH IN SENSE Fast Pulldown Current-Limit V V - V 70 75 80 mV THF IN SENSE Threshold Voltage (Note 3) GATE2 Pulldown Current I V < (V - V ) < V 335 435 535 A G2D TH IN SENSE THF GATE2 Fast Pulldown Current (V - V ) > V , IN SENSE THF I 80 125 200 mA G2DF (Note 3) V = (V + 4.5V) GATE2 OUT Maxim Integrated 2 www.maximintegrated.com