A programmable sustaining amplifier for reconfigurable MEMS-referenced oscillators

We describe a highly-programmable integrated sustaining amplifier for reconfigurable MEMS-referenced oscillators. The frequency response, voltage gain, and phase shift of the amplifier can be independently controlled using bias currents, thus enabling it to be interfaced with a variety of MEMS devices with resonant frequencies in the 10–120kHz range. The chip, which was designed in 0.5μm CMOS, also includes i) an automatic level control (ALC) circuit; and ii) an independently-adjustable background compensation network (BCN) that is used for canceling the parasitic electrical capacitance of the resonator. We present experimental data that confirms the functionality of individual circuit blocks and also the amplifier as a whole.