Linear Technology LTC4255CG Hot Swap Controller

The LTC4255CG is a versatile and robust hot swap controller designed by Linear Technology, now part of Analog Devices, to manage the insertion and removal of cards from a live backplane. This integrated circuit provides safe and controlled power-up sequencing, which is crucial in preventing damage to both the card and the backplane due to inrush currents or voltage spikes.

Key Features

• Wide Operating Range: The LTC4255CG is designed to operate over a wide voltage range, accommodating systems that use supply voltages from 9V to 80V. This makes it suitable for a variety of telecom, datacom, and industrial applications.
• Adjustable Current Limit: The current limit can be set with a single external resistor, providing flexibility in controlling the inrush current during hot insertion of boards.
• Overcurrent Protection: The device features fast acting current limit and foldback functionality to protect against overcurrent conditions, which is essential for system reliability.
• Gate Voltage Clamping: To protect external N-channel MOSFETs, the LTC4255CG clamps the gate voltage, ensuring safe operation under all conditions.
• Undervoltage and Overvoltage Lockout: The controller includes undervoltage (UV) and overvoltage (OV) lockout features to ensure that the power supply is within acceptable limits before allowing the card to power up.
• Power Good Output: A "power good" output signal is provided to indicate when the output voltage is within regulation, which can be used to enable downstream converters or to signal the system that the card is ready to operate.
• Thermal Shutdown: Integrated thermal shutdown protection automatically turns off the external MOSFET if the die temperature exceeds safe operating limits.
• Robust Packaging: The LTC4255CG is available in a 16-lead SSOP package, providing a compact solution with a thermal pad for enhanced heat dissipation.

Applications

The LTC4255CG is designed for use in systems that require hot swap capability such as servers, RAID systems, telecom switches, and network routers. Its ability to safely control the power for plug-in cards makes it an ideal choice for high-availability systems and mission-critical environments.

With its comprehensive set of features and protections, the LTC4255CG hot swap controller ensures that electronic cards can be inserted and removed from live systems with minimal risk of causing electrical damage, thus enhancing system uptime and reliability.