The MAX4271/MAX4272/MAX4273 comprise a complete family of integrated 3V to 12V hot-swap controllers. They allow the safe insertion and removal of circuit cards into live backplanes. The discharged filter capacitors of the circuit card provide a low impedance to the live backplane. High in-rush 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. This family of hot-swap controllers prevents such problems by 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 DualSpeed/BiLevel protection against short circuits, load glitches, and overcurrent conditions. In the event of a fault condition, the load is disconnected. Fault recovery is handled by unlatching (MAX4271), autoretry (MAX4272), or programmed (MAX4273) methods. The MAX4271 family includes many integrated features that reduce component count and design time. An on-board charge pump provides the gate drive for a low-cost, external n-FET. Integrated features like startup current regulation and current glitch protection eliminate external timing resistors and capacitors. Also featured are an open-drain status output to indicate a fault condition, and an adjustable overcurrent response time. The MAX4271 (latched fault protection) and MAX4272 (autoretry fault protection) come in 8-pin SO packages. The MAX4273 (full function) comes in the space-saving 16-pin QSOP package and 16-pin SO package. All parts are specified across the extended temperature range, and have an absolute maximum rating of 15V to provide extra protection against inductive kickback during board removal.
Provide Safe Hot Swap for +3V to +12V Power Supplies with Few External Components
Unique Current Regulation Architecture Minimizes n-FET Linear Mode Duration
Autoretry Feature (MAX4272/MAX4273)
DualSpeed/BiLevel Current Limit Protects Against Current Glitches and Short Circuits
Power-On RESET (MAX4273)
15V Absolute Maximum Rating Protects Against Inductive Kickbacks During Board Removal
Internal Charge Pump Generates Gate Drive for External n-MOSFET