PORTLAND, Ore. — Touted as the world's thinnest MEMS oscillator at just 0.25 millimeters, a new device is being targeted at applications such as smart cards, ultra-thin cellphones, system-in-package modules, flash storage units and other multichip modules.

SiTime Corp. (Sunnyvale, Calif.) said it unstacked two dies in its previous SiTime8002 MEMS oscillator, slimming it to one-third its previous thickness but increasing its surface area.

"This oscillator is the thinnest out there, by almost three times," claimed Piyush Sevalia, vice president of marketing for SiTime. The company said the thinnest device prior to SiTime's was 0.7 mm.

Deep-reactive ion etching creates deep, high-aspect ratio silicon structures--the vibrating element of the world's thinnest MEMS oscillator.

SiTime's SiT8002 used die stacking to combine the mechanical MEMS die and its ASIC, but the new SiT8002XT puts the two die side-by-side. The new chip measures 3.5 by 3 mm, but is only 0.25-mm thick compared to 0.85 mm previously.

The four-pad XLLGA package used for the SiT8002XT can be factory programmed in less than 48 hours at frequencies between 1 and 125 MHz, voltages between 1.8 and 3.3 volts and either 100 or 500 parts per million frequency tolerance.

Samples are available now, with production quantities scheduled for the fourth quarter of 2008.