Dear Mr. Yong

As you pointed correctly, the key idea of force feedback is to use negative
feedback to increase the spring constant. For me, this looks same as the idea to
use negative feedback with resistors to tune the Opamp gain precisely. The
sensitivity of accelerometer is inversely proportional to the spring constant in
case of constant mass. I think it is much easier to tune the XL sensitivity with
adjusting feedback gain (maybe by adjusting resistor value) instead of laser-
trimming suspended, fragile polysilicon springs.

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Sangwoo Lee, Ph.D.
Member of Research Staff

MEMS Laboratory
Samsung Advanced Institude of Technology
P.O. Box 111, Suwon 440-600, Korea

Tel: +82 31 280 9465
Fax: +82 31 280 9473
Email: lsw@sait.samsung.co.kr
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