MAX5977B

 

Part Number	Replacement	Explanation

Description

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The MAX5977A/MAX5977B hot-swap controllers provide complete protection for systems with a 1V to 16V single-supply voltage.

During the initial insertion, the hot-swap controllers limit the inrush current from damaging the board or from shorting out the backplane. When the input voltage is above the undervoltage threshold and below the overvoltage threshold, a 5µA current source powered from the internal 5V charge pump drives the gate of an external n-channel MOSFET providing a slow turn-on response. An internal current-sense amplifier in the IC monitors the current across an external shunt resistor providing current sensing for wide input-sense voltage range. The devices provide two levels of overcurrent circuit-breaker protections: a fast-trip threshold for a fast turn-off and a lower slow-trip threshold for a delayed turn-off.

Exceeding either of the overcurrent circuit-breaker thresholds will force the device into fault mode where the external n-channel MOSFET is disabled. The MAX5977 is available in two versions which provide a latched off (MAX5977A) or autoretry (MAX5977B) output when the device is in fault mode.

A calibration mode allows further calibration of the integrated transconductance amplifier for production testing of the final design. The devices are offered in a 20-pin, 4mm x 4mm, TQFN-EP package and are fully specified from -40°C to +85°C.

MAX5977A, MAX5977B: Typical Operating Circuit Enlarge+

Key Features

• 1% Accurate Current-Sense Amplifier Output
• Hot-Swap Monitors Operation from 1V to 16V
• Integrated Charge Pump Fully Enhances the External n-Channel FET (V_GATE = V_IN + 5V)
• VariableSpeed/BiLevel™ Fault Protection Provides Electronic Circuit-Breaker Function
• Output Latched Off After Fault Condition (MAX5977A)
• Autoretry After Fault Condition (MAX5977B)
• Power-Good Indicator
• Calibration Mode
• Small, 20-Pin, 4mm x 4mm, TQFN-EP Package

Applications/Uses

• General Hot-Swap
• Network Switches and Routers
• Servers
• Storage Systems