3D Ultrasonic Rangefinder on a Chip

An ultrasonic 3D rangefinder uses an array of AlN MEMS transducers and custom readout electronics to localize targets over a ±45° field of view up to 1 m away. The rms position error at 0.5 m range is 0.4 mm, 0.2 °, and 0.8 ° for the range, x-angle, and y-angle axes, respectively. The 0.18 μm CMOS ASIC comprises 10 independent channels with separate high voltage transmitters, readout amplifiers, and switched-capacitor bandpass ΣΔ ADCs with built-in continuous time anti-alias filtering. For a 1 m maximum range, power dissipation is 400 μW at 30 fps. For a 0.3 m maximum range, the power dissipation scales to 5 μW/ch at 10 fps.