The MAX5949A/MAX5949B are hot-swap controllers that allow a circuit card to be safely hot plugged into a live backplane. The MAX5949A/MAX5949B operate from -20V to -80V and are well-suited for -48V power systems. These devices are pin and function compatible with the LT4250 and pin compatible with the LT1640.

The MAX5949A/MAX5949B provide a controlled turn-on to circuit cards preventing glitches on the power-supply rail and damage to board connectors and components. The MAX5949A/MAX5949B provide undervoltage, overvoltage, and overcurrent protection. These devices ensure the input voltage is stable and within tolerance before applying power to the load.

Both the MAX5949A and MAX5949B protect a system against overcurrent and short-circuit conditions by turning off the external MOSFET in the event of a fault condition. The MAX5949A/MAX5949B also provide protection against input voltage steps. During an input voltage step, the MAX5949A/MAX5949B limit the current drawn by the load to a safe level without turning off power to the load.

Both devices feature an open-drain power-good status output (PWRGD-bar for the MAX5949A or PWRGD for the MAX5949B) that can be used to enable downstream converters.

The MAX5949A/MAX5949B are available in an 8-pin SO package. Both devices are specified for the extended -40°C to +85°C temperature range.

Applications

• -48V Distributed Power Systems
• Base-Station Line Cards
• Central-Office Line Cards
• Central-Office Switching
• Negative Power-Supply Controls
• Network Routers and Switches
• Server Line Cards
• Telecom Line Cards