The MAX5920A/MAX5920B are hot-swap controllers that allow a circuit card to be safely hot plugged into a live backplane. The MAX5920A/MAX5920B 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 MAX5920A/MAX5920B provide a controlled turn-on to circuit cards preventing glitches on the power-supply rail and damage to board connectors and components. The MAX5920A/MAX5920B 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 MAX5920A and MAX5920B protect a system against overcurrent and short-circuit conditions by turning off the external MOSFET in the event of a fault condition. The MAX5920A/MAX5920B also provide protection against input voltage steps. During an input voltage step, the MAX5920A/MAX5920B 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 (active-low PWRGD for the MAX5920A or PWRGD for the MAX5920B) that can be used to enable downstream converters. A built-in thermal-shutdown feature is also included to protect the external MOSFET in case of overheating. The MAX5920A/MAX5920B are available in an 8-pin SO package. Both devices are specified for the extended -40°C to +85°C temperature range.
Feature
- Allows Safe Board Insertion and Removal from a Live -48V Backplane
- Pin- and Function-Compatible with LT4250L (MAX5920A)
- Pin-Compatible with LT1640L (MAX5920A)
- Pin- and Function-Compatible with LT4250H (MAX5920B)
- Pin-Compatible with LT1640H (MAX5920B)
- Circuit-Breaker Immunity to Input Voltage Steps and Current Spikes
- Withstands -100V Input Transients with No External Components
- Programmable Inrush and Short-Circuit Current Limits
- Operates from -20V to -80V
- Programmable Overvoltage Protection
- Programmable Undervoltage Lockout
- Powers Up into a Shorted Load
- Power-Good Control Output
- Thermal Shutdown Protects External MOSFET
Applications
- Base-Station Line Cards
- Central-Office Line Cards
- Network Routers and Switches
- Server Line Cards
- Telecom Line Cards
