Hergen Kapels

Implantable low power integrated pressure sensor system for minimal invasive telemetric patient monitoring

A new low power integrated pressure sensor system with digital output (1 bit PDM signal) for medical applications is presented. The absolute pressure sensor comprising 400 nm thick surface micromachined polysilicon membranes for capacitive pressure detection and a monolithic integrated 2/sup nd/ order sigma-delta-modulator including voltage reference and timing generator is extremely miniaturized on an area of approximately 3 mm/sup 2/. For protection and biocompatibility reasons the sensor is coated with a silicone elastomer of up to 100 /spl mu/m thickness, which does not influence the sensors performance. The sensor system was tested in vitro in physiological NaCl solution, showing excellent results compared to a commercially available reference sensor. The sensor system is working well down to a supply voltage of 2.2 V at a power consumption of 0.5 mW. The resolution is better than 12 bit. Due to the small chip area, low power consumption and cost effective production process, the sensor is ideal for medical applications, e.g. in combination with telemetric power and data transmission as an implantable sensor to reduce the mortality risk of intensive care patients.

“Cavity-Micromachining” Technology: Zero-Package Solution for Inertial Sensors

“Cavity-Micromachining” is a technology that enables to ship MEMS products like inertial sensors as Flip-Chips or in any other low-cost package. Moveable structures are buried inside cavities below the wafer surface. The protection against mechanical and environmental influences is done with deposited layers on wafer-level instead of using wafer-bonding. Therefore the chips are much smaller and can be made thin enough to fit into any cheap standard package or module.

Monolithic Surface-Micromachined Sensor System for High Pressure Applications

A new generation of Pressure Sensor ICs for automotive and industrial applications will be presented. Surface μ-machined capacitive sensor cells are embedded into a standard BiCMOS-Process, yielding a monolithically integrated High-Pressure-Sensor-System. On-Chip signal conditioning includes functions such as detection of pressure dependent capacity, A/D conversion, digital calibration, temperature compensation, D/A reconversion and ratiometric analog output. The sensor systems are operating in pressure ranges up to 400 bar with an accuracy of 1.5% in a premoulded DSOF-8 standard package. With several 40 bar and 200 bar sensor systems overpressure tests up to 600 bar were passed succesfully.