Transient suppressors shrink for portable uses

Two new families of transient voltage suppressors for 3.3V operation feature extremely low clamping voltage and leakage current values.

Semtech has released two families of transient voltage suppressors (TVSs) for 3.3V operation featuring extremely low clamping voltage and leakage current values.

Designed to guard sensitive, low-voltage circuits against damage or latch-up caused by electrostatic discharge, lightning, and other destructive voltage transients, both the SMS3.3 and the SMF3.3 arrays protect up to four signal lines operating at 3.3V.

One of the most noteworthy specifications of the devices is a clamping voltage typically limited to less than 5V.

Both arrays feature an astonishing low leakage current of less than 0.5A, and typical overall capacitance of less than 50pF for the SMS3.3 and less than 30pF for SMF3.3.

The two arrays are virtually identical, except for their package.

The SMS3.3 comes in an SOT-23; the SMF3.3 in an SC-70.

The blend of rock-bottom capacitance and leakage current with true 3.3V operation make the SMS3.3 and SMF3.3 perfect candidates for use in portable, battery-operated, and wireless products including cellular and cordless phones, personal digital assistants, and notebook computers.

In addition, both devices serve equally well in desktop computers, servers, game systems, peripheral devices, analogue inputs, and instrumentation.

Both TVS arrays meet the ESD protection requirements specified by IEC 61000-4-2 Level 4 (8kV contact, 15kV air), as well as the EFT requirements of IEC 61000-4-4 (40A, 5/50ns), and the lightning requirements of IEC 61000-4-5 (12A, 8/20us).

"The SMS3.3 and SMF3.3 bring ultra-low power consumption to a rich and growing family of low-voltage, low capacitance devices", said Tom Dugan, director of marketing for Semtech's Protection Products Group.

"Both offer pin-compatibility to counterparts in our 5V line, simplifying upgrades as well as redesigns of portable, wireless, and battery powered electronic products, where small size and high performance matter most".

Like other Semtech TVS arrays, the SMS3.3 and SMF3.3 are built using Semtech's patented, solid-state enhanced punchthrough diode (EPD) fabrication process, which gives the SMS3.3 and SMF3.3 their exceptional low-voltage protection, low leakage current, and high-frequency performance specifications compared to competitive transient protection devices, including PN junction types.

In quantities of 3000 per reel, the SMS3.3 TVS array in an SOT23-6L package sells for $0.33 each; the SMF3.3 TVS array in an SC70-5L package, for $0.28 each.

Samples are available now in tape-and-reel format, with volume quantities forthcoming.

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