An integrated transmitter/receiver IC for an ultrasound presence detection microsystem uses silicon membranes as the transducer. The transmitter membrane uses an electro-mechanical oscillator to emit ultrasound at 80kHz. The receiver with 8uV input-referred noise uses self-calibration to maximize sensitivity up to 10cm distance.
A pressure tranducer with a piezoresistive microbridge, digitally controlled readout electronics, and a nonlinear temperature compensator based on spline functions are integrated on a single 34mm2 CMOS chip. With temperature compensation enabled, the temperature coefficient drops from 1315 ppm/K to 86ppm/K.
A single-chip 200x200-element sensor array for fingerprint acquisition produces a gray-scale image linearly related to the depth of the ridges. The fingerprint is captured at 10Frames/s by pressing the finger skin onto the chip surface. The sensor measures 15x15mm2 and has power consumption <600uW.
A 3-axis surface micromachined accelerometer is implemented on a single 4x4mm2 die. Use of correlated double sampling, input common-mode feedback, and forward path compensation results in a measured dynamic range of 84dB, 81dB, and 70dB for the x-, y-, and z-, axes respectively.
A dynamic differential Hall IC with a current interface detects magnetic fields down to a few 100uT and corresponding Hall voltages on the order of 10uV in an automotive environment over a temperature range of -50 to 210deg C. The IC operates over a power supply range of 4.5 to 30V with power supply rejection and polarity reversal protection.
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