The IEEE Solid-State Circuits and Technology Committee (SSCTC) held its annual fall workshop 14-15 October 1999 in Arlington, VA. The workshop on "MEMS Interface Circuits" was organized by Steve Garverick and Darrin Young of Case Western Reserve University. Presentations were interdisciplinary and included technology, modeling, and simulation of a variety of micro-machined transducers as well as details of interface circuit design for these devices.
The 17 presentations during the workshop were divided into five areas: Electrostatic Actuators, Capacitive Sensors, Modeling and CAD, Wireless Sensing and Communication, and Inertial Sensors. Speakers represented seven international universities, eight corporations, and a government agency.
R. Meier (Texas Instruments) used 3-D graphics to explain the mechanics of a digital micromirror and the technique for biasing it into an unstable position to allow rapid switching according to row-column addressing. K. Fukatsu (Tokimec) and I. Lyusternik (CWRU) described their micromotors with electrostatically levitated rotors, the former using independent, continuous-time control loops for each of the six control dimensions (x, y, z, and rotation/tilt about each), and the latter using a single, time-multiplexed, discrete-time control loop.
Three presenters described their work in data acquisition from MEMS capacitive sensors. R. Carley (CMU) described an experimental integrated sensor array with 0.02-aF/ sqrt(Hz) noise spectral density, i.e., 20-aF resolution for 1-MHz signal bandwidth. K. Su (Microsensors) presented a general-purpose, programmable IC for MEMS capacitive sensors that has achieved 4 aF/ sqrt(Hz) resolution in the presence of relatively large packaging capacitance, employing a combination of switched-capacitor and continuous-time filters that use time-constant multiplier circuits to implement the relatively low cut-off frequencies (e.g., 100 Hz) required by inertial and other sensors. A. Chavan (UM) described an IC that includes five pressure sensors and interface to a general-purpose computer, including an on-chip high-voltage generator for stimulation of the sensors.
The Modeling and CAD area featured presentations by G. Fedder (CMU) and M. da Silva (Microcosm Technologies). Wireless Sensing and Communication included talks by D. Young (UCB), W. Kaiser, (UCLA), M. Gaitan (NIST), and C. Hagleitner (SFIT). The session on Inertial Sensors featured N. Yazdi (ASU), L. Spangler (Ford Microelectronics), A. Seshia (UCB), J. Geen (Analog Devices), and M. Shaw (Motorola).
Information regarding this and previous SSCTC workshops has been posted at www.sscs.org/ssctw/. This year's fall SSCTC Workshop will be held Thursday, 12 October and Friday, 13 October 2000, in Arlington, VA at the Key Bridge Marriott. Please refer to the Web page for more details as they become available.
Steve Garverick
SSCTC Cochair
Representative to Sensors Council
IEEE Solid-State Circuits Society
slg9@po.cwru.edu