MAX5909

The MAX5904MAX5909 dual hot-swap controllers provide complete protection for dual-supply systems. These devices hot swap two supplies ranging from +1V to +13.2V, provided one supply is at or above 2.7V, allowing the safe insertion and removal of circuit cards into live backplanes.

The discharged filter capacitors of the MAX5909 provide low impedance to the live backplane. High inrush currents from the backplane to the circuit card can burn up connectors and components, or momentarily collapse the backplane power supply leading to a system reset. The MAX5909 of hot-swap controllers prevents such problems by gradually ramping up the output voltage and regulating the current to a preset limit when the board is plugged in, allowing the system to stabilize safely. After the startup cycle is completed, two on-chip comparators provide VariableSpeed/BiLevel™ protection against short-circuit and overcurrent faults, as well as immunity against system noise and load transients. In the event of a fault condition, the load is disconnected.

The MAX5905/MAX5907/MAX5909 must be unlatched after a fault, and the MAX5904/MAX5906/MAX5908 automatically restart after a fault. The MAX5904 family offers a variety of options to reduce component count and design time. All devices integrate an on-board charge pump to drive the gates of low-cost, external N-channel MOSFETs. The MAX5909 offer integrated features like startup current regulation and current glitch protection to eliminate external timing resistors and capacitors. The MAX5906MAX5909 provide an opendrain status output, an adjustable startup timer, an adjustable current limit, an uncommitted comparator, and output undervoltage/overvoltage monitoring.

The MAX5904/MAX5905 are available in 8-pin SO packages. The MAX5909 is available in spacesaving 16-pin QSOP packages.