Electronic interfaces between MEMS and higher-level measurement and control systems may include not only drive and read-out electronics but also comprehensive built-in test blocks and communication interfaces such as SPI (synchronous serial peripheral interface), CAN-bus (asynchronous controller area network), I2C (inter-integrated circuit, a two-wire serial interface developed by Philips), and others.

Decisive for efficient use of a sensing element is the front-end electronics, which dominantly determines the signal-to-noise ratio, linearity, and power consumption of the whole sensor system [Hagleitner 2005]. The front-end electronics must be selected and matched with the specific sensor properties. Consequently, the design of the front-end electronics is an inseparable part of the system design.

In this chapter some principles and basic blocks for forming the front-end electronics are presented. In contrast, the implementation of high-level signal processing and control blocks according to the system concept is usually the task of IC-design specialists and follows the road of ASIC-design methodologies. It is not considered here.

However, some interrelations between front-end and high-level electronics must be evaluated before starting a system design. Front-end electronics is analog, whereas high-level signal processing is digital. Low-noise input amplifiers occupy large areas while fast digital signal processing requires high integration densities. Hence, analog front-ends can be realized advantageously in moderate technologies such as 0.25–3-μm CMOS. Cost savings in digital processing, however, call for deep-sub-micrometer technologies. The technological compromise depends on the relation between the areas occupied by the two types of circuitry.