A 4-bit 1 GHz sub-half micrometer CMOS/SOS flash analog-to-digital converter using focused ion beam implants

A description is given of a novel 4-bit, ultrafast, low-power flash analog-to-digital converter (ADC) chip that was fabricated using digital CMOS/SOS SPEAR technology with sub-half-micrometer (0.3- mu m) gates and focused-ion-beam (FIB) channel implants. The FIB technology allows localized implants to be used to customize the threshold voltages of the MOSFETs used in each comparator. The maximum sample rate of the circuit exceed 1 GHz at a supply voltage of 5.0 V and decreased slightly to 900 MHz when the supply voltage was lowered to 3.3 V. the power dissipation, apart from the output buffers, at 3.3 V and 900 MHz was only 80 mW. Because of the very low power dissipation and small size (<1 mm/sup 2/), this 4-bit ADC is ideal for inclusion on digital signal-processing chips with no compromise in speed.<
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