MAX15068

Description

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The MAX15068 offers ORing function and hot-swap features for two input-supply-rail applications requiring the safe insertion and removal of circuit line cards from a live backplane. The device integrates dual ORing MOSFET controllers, a single hot-swap controller, electronic circuit-breaker protection, and power monitoring in a single package. The device is designed to operate from 2.9V to 18V supply voltages.

The device regulates the forward voltage drop across the ORing MOSFETs to ensure smooth current transfer from one supply to the other without oscillation. The ORing MOSFET turns on quickly to reduce the load voltage drop during supply switchover. If the input supply fails or is shorted, a fast turn-off minimizes reverse-current transients.

The device implements a foldback current limit during hot-swap startup in order to control inrush current, thereby lowering di/dt and keeping the operation of the hot-swap MOSFET under safe operating area (SOA). An internal 70ms timer starts counting when the device enters the hot-swap startup phase. After the hot-swap startup cycle is completed, on-chip comparators provide active current-limit protection against short-circuit and overcurrent faults. The load is disconnected from the input quickly in the event of a fault condition.

The device provides current monitoring from 3A to 8A (V_IN = 12V, T_A = +25°C with R_SENSE = 3mΩ) with ±0.5% accuracy. A voltage proportional to the input current delivered to the system could be read directly at the IPMON pin.

The device is factory-calibrated to deliver accurate overcurrent protection with ±5% accuracy. During an overcurrent-fault condition, the device enters an autoretry mode. The device features an adjustable slew-rate control during startup. Additional features include power-good and fault-indicator outputs.

The MAX15068 is available in a 20-pin, (4mm x 5mm) TQFN package and is specified from a -40°C to +125°C operating temperature range.

Key Features

• 2.9V to 18V Operating Voltage Range (ORing and Hot Swap)
• 4.8V to 18V Operating Voltage Range (Current Monitor)
• Seamless Power Transition of Redundant Supplies
• Controls N-Channel MOSFETs
• < 0.5µs Reverse Turn-Off Time
• ±0.5% Current Monitoring (Typ)
• Programmable Slew-Rate Control
• Adjustable Current-Limit Fault Delay
• Programmable Circuit-Breaker Current Threshold
• Inrush Current Regulated at Startup with Programmable SOA Control
• Programmable Undervoltage Lockout
• Small (4mm × 5mm) TQFN Package

Applications/Uses

• Baseband Station
• Computer Systems and Servers
• Redundant Power Supplies
• Storage Bridge Bay
• Supply Holdup
• Telecom Networks