Switches handle high currents without stalling

Bettyann Liotta

eeProductCenter (11/04/2005 1:17 PM ET)

San Jose, Calif. — Micrel Inc. rolled out six new additions to its family of high-current power switches with adjustable current limiting and Kickstart, a unique feature that is said to handle high current surge devices without the stalling or stuttering caused by standard current limiting devices.

The MIC2007/08/09 feature adjustable current limiting, and the MIC2017/18/19 offer both adjustable current capability and Kickstart.

The chips are part of the expanding family of MIC20xx power distribution switches introduced just last quarter. The ICs are aimed at PCs, set-top boxes, docking stations, game controllers and USB host devices — where current limiting as protection against excessive loads and short circuits is required.

"As an ever increasing number of products add USB functionality, designers are requiring more flexibility in their power management system," said Bob Whelton, Micrel's executive vice president operations. "The new MIC20xx series increases the number of options for designers and gives them the head room they require for increasingly unpredictable power demands in USB devices."

The MIC2007/08/09 and MIC2017/18/19 feature the industry's highest power-to-footprint ratio: 0.5 A/mm², according to Whelton. In addition, these ICs are among the first to offer adjustable current limiting, up to 2 A, in such small packages, he said.

Adjustable current limiting allows the customer to set a limit of his or her own choosing rather than choosing from a list of pre-set factory limits. Adjustability also helps inventory control as, with adjustable current capability, one IC can easily address the power needs of many designs.

The ICs all offer 100 milliohm maximum on-resistance and an adjustable current limit in the smallest form factors available on the market today. These chips are capable of serving multiple USB ports. Standard features include a 2.5 V to 5.5 V operating range, output enable control input, thermal protection, under voltage lock-out, low quiescent current and fault masking, which prevents nuisance alarms on current surges or hot plug events.

The MIC2007/08/09 and the MIC2017/18/19 are available in volume quantities and in two package options; SOT-23 and 2 x 2mm MLF. Pricing starts at 69 cents in 1K quantity for the SOT-23 and 80 cents in 1K quantity for MLF packaging. Click here for the MIC2007/2017 data sheets. Click here for the MIC2008/2018 data sheets.Click here for the MIC2009/2019 data sheets.

Micrel, 1-408-944-0800, www.Micrel.com.

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