A three-axis micromachined accelerometer with a CMOS position-senseinterface and digital offset-trim electronics
Lemkin, M.; Boser, B.E.
Solid-State Circuits, IEEE Journal of
Volume 34, Issue 4, Apr 1999 Page(s):456 - 468
Digital Object Identifier 10.1109/4.753678
Summary:This paper describes a three-axis accelerometer implemented in a
surface-micromachining technology with integrated CMOS. The
accelerometer measures changes in a capacitive half-bridge to detect
deflections of a proof mass, which result from acceleration input. The
half-bridge is connected to a fully differential position-sense
interface, the output of which is used for one-bit force feedback. By
enclosing the proof mass in a one-bit feedback loop, simultaneous force
balancing and analog-to-digital conversion are achieved. On-chip digital
offset-trim electronics enable compensation of random offset in the
electronic interface. Analytical performance calculations are shown to
accurately model device behaviour. The fabricated single-chip
accelerometer measures 4×4 mm2, draws 27 mA from a 5-V
supply, and has a dynamic range of 84, 81, and 70 dB along the x-, y-,
and z-axes, respectively
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