A 12-bit 500-ns subranging ADC

A subranging 12-b ADC (analog/digital converter) with analog and digital correction has been developed in a high-speed bipolar process. A conversion is performed in four stages. The settling requirement of the subtraction digital/analog converters is postponed until the final stage, resulting in a conversion time of 500 ns. The use of Ti-W fuse-link based trimming permits the critical circuit components to be adjusted at the wafer level with only a few pads. The circuit has been implemented in a die area of 25 mm/sup 2/ and dissipates 650 mW.<
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