Low-power clock targets wearables - Embedded.com

Low-power clock targets wearables

Wearable devices challenge their designers to make them low power enough to run on batteries for days, weeks, even months — if possible. The power hog is usually the application processor and the RF section, but even the oscillators can make a different if they can be reduced to the microAmp rather than the more typical milliAmp range.

Here SiTime claims it has reduced the power consumed by its SiT8021 oscillator by 90 percent compared to traditional crystal oscillators, not to mention being 70 percent lighter and 40 percent smaller.

“SiTime has always improvised constantly to improve their product line,” Tony Massimini, chief of technology at Semico Research told EE Times. “By focusing on the wearable market, and getting power as low as 100 microAmps and the size to 1.5-by-.8, they have produced a pretty impressive reduction in supply current and size.”

The four-bar oscillator for the SiT8021 for wearables has a novel shape in order to require lower power to oscillate.(Source: SiTime)

The four-bar oscillator for the SiT8021 for wearables has a novel shape in order to require lower power to oscillate. (Source: SiTime)

But lower power, less weight, and smaller size are not the only advantages of going with a SiTime MEMS oscillator, according to Massimini.

“Another advantage that is very compelling is that they don't have to make a different oscillator for every frequency, but can tune them over a wide range from 1-to-26-megaHertz with ±100 parts per million [PPM] frequency stability which will allow it to work with a lot of different chips, different needs and different sampling rates,” Massimini told us. “In general, SiTime has also demonstrated very high reliability and accuracy in their products. We predict huge grown, operating independently from Megachips, but with its sales force helping them out. And its not just for wearables, but for lots of different apps need timing and connectivity.”

The package for SiTime's measures a scant 1.5-by-0.8-by-0.55 millimeters.(Source: SiTime)

The package for SiTime's measures a scant 1.5-by-0.8-by-0.55 millimeters. (Source: SiTime)

SiTime fancies itself the last MEMS oscillator maker standing, with its burgeoning sales compared to its old competitor, Discera Inc. (San Jose, Calif.) and its new competitor Silicon Labs (Austin, Texas) with only a few parts in its catalog. In fact, according to Piyush Sevalia, SiTime executive vice president, it already has an accumulated sales of over a quarter of a billion (270 million) units, sold 60 million units last year and now that it has merged with MegaChips Corp. (Osaka, Japan) expects to double its sales in 2015 to 120 million units, thanks to help from MegaChips mega-sales force.

“We are still operating in the U.S, as an independent subsidy, but MegaChips is helping us out with sales,” Sevalia told EE Times. “We are an easy choice to make since we are the only MEMS maker with a Lifetime Warranty, yields in the 95 percent range, a 1.6 DPPM [defective parts per million] and have had zero failures in the field so far.”

According to Sevalia, their parts are lighter than quartz crystals, because they can be packaged in plastic–rather than hermetically sealed ceramic packages and can be programmed at the factory to drive five or six–depending on the part–different loads, thus enabling customers to get the drive power they need without wasting power.

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