Maxim Integrated Products has introduced new hot-swap controllers with 1% accurate current-sense amplifier output.
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.
An evaluation kit is available: MAX5977AEVKIT
Key Features Applications/Uses
- 1% Accurate Current-Sense Amplifier Output
- Hot-Swap Monitors Operation from 1V to 16V
- Integrated Charge Pump Fully Enhances the External n-Channel FET (VGATE = VIN + 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
