A-to-d converter of the successive-approximation type

Abstract From the Canadian patent

An integrated-circuit analog-to-digigal converter of the successive-approximation type formed on a single monolithic chip. The converter is made by a diffusion process wherein certain portions of the chip are formed with normalmode linear transistors, and other portions are formed with inverted mode I2L transistors. The normal-mode transistors provide a switchable current-source DAC a set of three-state, output buffers, and a comparator The inverted mode transistors provide an internal clock and successive-approrximatior control circuitry for the DAC. The chip also includes a voltage reference to provide for absolute analog-to-digital conversions.