New Industry Products

LTC Presents New LTC4255 Hot-Swap Controller

July 09, 2002 by Jeff Shepard

Linear Technology Corp. (Milpitas, CA) introduced the LTC4255, a quad, -48V, hot-swap controller that safely controls powered Ethernet ports and provides open-circuit detection and short-circuit protection. The LTC4255 enables a networking hub and router to become power-sourcing equipment supporting the emerging IEEE 802.3af specification, which will allow -48V to be delivered over standard CAT-5 Ethernet cable to powered devices such as phones or wireless access points.

The LTC4255 provides a four-port solution in very little board space with extensive software control. Through a two-wire serial interface, the LTC4255 offers separate on/off control, latch-off or auto-retry response to short-circuit faults, notification of cable disconnect, power-good indication, and addressing for up to 128 ports per board. A separate interrupt signal eliminates the need for continuous software polling. The LTC4255 uses an external n-channel MOSFET and an external sense resistor to detect over-current or open-circuit (under-current) faults. Active current limiting with fold-back controls over-current faults and limits power dissipation in the MOSFET during faults or at start-up.

The LTC4255 is offered in the 28-pin, SSOP package. Pricing starts at $5.90 each for 1,000-piece quantities.