Application specific silicon integrated circuit

An integrated circuit (IC), or chip, represents the brains behind all electronic devices. An IC is a compilation of billions of complex subunits such as transistors, resistors, capacitors, and diodes that are all interconnected in a specific manner depending on the desired application. Incredibly, this minute world of microcircuitry is fitted onto the surface of a thin silicon substrate about the size of a fingernail Though ICs have only been used since the early 1970s, consider some of the ways our lives have been changed ... 

Chip stacks. A recent approach to increasing component densities is to connect the die or chip devices vertically as a chip stack instead of assembling them horizontally on a substrate. The silicon chips are first thinned to several mils (2-4 mils), then bonded together. Where the chips are of different sizes, such as an application-specific integrated-circuit (ASIC)... 

High-Value Materials. Apart from certain chemical compounds that are required in high purity form, the main application of zone refinement is the production of silicon single crystals for use in integrated-circuit chips. The process requires that a great deal of care be taken so that the resulting material meets the desired specifications. 

The architecture of a wireless capsule system named the lab-in-a-pill (LIAP) is presented in Fig. 7.13 [113]. It consists of pH and temperature sensors and a custom-made application-specific integrated readout circuit. The pH sensor is a micro-fabricated ISFET with Ag/AgCl reference electrode. The temperature sensor is an n-channel silicon diode. The system consumes 15.5 mW. The circuit has a power saving feature to operate it for 42 h. 

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