Compact diodes aim for handset ESD protection

The MicroClamp family of ultrasmall transient voltage suppressors (TVS) is designed expressly for ESD protection on cellphones, PDAs, digital cameras, and other portable electronic designs.

The MicroClamp family of ultrasmall transient voltage suppressors (TVS) is designed expressly for ESD protection on cellphones, PDAs, digital cameras, and other portable electronic designs.

The first product in the family is the uClampT0501H, a TVS diode in a two-lead SOD-523 package measuring 0.9 x 1.7 x 0.6mm.

The uClamp0501H offers ESD protection in excess of +/-8kV contact, +/-15kV air per IEC61000-4-2 level 4 requirements, an industry ESD standard that must be met by mobile phone manufacturers.

"Today's portable devices are growing in functionality as manufacturers add large colour screens, Internet access capabilities and other features, which puts board space in an already small design at an even higher premium", said Tom Dugan, Semtech's Director of Protection Products.

"The uClamp0501H gives manufacturers a new way to protect their devices and save board space thanks to Semtech's process technology expertise which has allowed us to provide superior protection characteristics while shrinking the package size dramatically".

Designers don't always have the option to use multi-line arrays on a densely packed circuit board.

Because the uClamp0501H is designed primarily for use in portable devices, its small size and single-line topology grant designers more flexibility to add effective ESD protection around the board as required, especially in areas where human contact - the most common generator of ESD - is likely, such as keypads, battery contacts or data and I/O lines.

In a portable design, the uClamp0501H is placed in parallel with the protected circuit and becomes a low impedance path during an ESD event.

Harmful current is safely shunted to ground while voltage across the protected circuit is minimised.

The uClamp0501H features low clamping voltage, which puts less stress on the protected IC during an ESD event, and is appropriate for the most sensitive circuits such as baseband controllers in cellular phones.

And unlike competing technologies used in the same application, the uClamp0501H does not degrade after multiple ESD strikes.

Samples of the uClamp0501H are available immediately.

Volume production is scheduled for ramping in May with devices priced at $0.24 each in 1000-piece lots.

Semtech offers comprehensive design assistance, including field- and factory-based support.

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