Hot swap protector integrates temperature sensing

ON Semiconductor has expanded its Smart HotPlug family with the introduction of the NIS5102 high side hot swap protection IC with built-in charge pump and accurate temperature-sensing circuitry.

ON Semiconductor has expanded its Smart HotPlug family with the introduction of the NIS5102 high side hot swap protection IC with built-in charge pump and accurate temperature-sensing circuitry.

Designed for computing and telecomms applications, it combines a power MOSFET with control circuitry and thermal protection.

This integrated approach simplifies implementation of vital "hot swap" protection in high availability +12V systems and is ideal for use in distributed power systems, servers, disk arrays and powered board insertion applications.

"The common industry solution for hot swap protection of +12V applications requires the implementation of a controller, external MOSFET and power sense resistor - often from separate suppliers - and more than a dozen passive components", said Barry Brinkman, ON Semiconductor Product Marketing Manager.

"In comparison, the NIS5102 - programmed with three standard chip resistors - delivers the industry's most reliable thermal protection thanks to built-in temperature-sensing circuitry".

The NIS5102 offers designers an integrated solution for limiting inrush current generated when plugging electronic equipment into a running or "hot" system without causing interruption or damage to the system or the electronic equipment.

Specifically, it is designed to allow safe insertion and removal of electronic equipment into +12V backplanes.

Although a growing number of hot-swap controllers are being introduced to the market, the NIS5102 is the only device available with a low 10mohm, 18V rated integrated smart MOSFET.

By integrating a smart MOSFET with a current mirror into the NIS5102 - specifically, a SenseFET - only a fraction of the load current is sensed across the sense resistor.

This eliminates the need for a larger and more expensive external power sense resistor.

Temperature-sensing diodes provide accurate and hassle-free thermal protection.

An adjustable current-limiting feature enables the designer to set the maximum inrush current from 20A to less than an 1A.

Undervoltage and overvoltage lockouts prevent the load from "seeing" a potentially unsafe operating voltage.

This device can run at a 10A continuous current with only a 0.5in2 copper pad and no additional heatsink or air flow.

The NIS5102 is the second integrated Smart HotPlug devices introduced by ON Semiconductor.

Last year, the NIS5101 hot swap protection device, designed for -48V backplanes, was debuted.

By the end of 2005, three additional Smart HotPlug devices will be launched.

The NIS5102QP1HT1G (latch) and NIS5102QP2HT1G (auto-retry) are available in 12-pin DFN Pb-free packages that measure 9 x 9mm.

The devices are priced at $2.38 per unit in 2000-unit quantities.

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