The DAC729 sets the standard in very high accuracy digital-to-analog conversion. It is supplied from the factory at a guaranteed linearity of 16 bits, and is useradjustable to 18-bit linearity (1LSB = FSR/262144). To attain this high level of accuracy, the design takes advantage of Burr-Brown's thin-film monolithic DAC process, dielectric op amp process, hybrid capabilities, and advanced test and laser-trim techniques. The DAC729 hybrid layout is specifically partitioned to minimize the effects of external load-currentinduced thermal errors. The op amp design consists of a fast settling precision op amp with a current buffer within the feedback loop. This buffer isolates the load from the precision op amp, which results in a fast settling (8s to 16 bits) output. The standard 40-pin package offers full hermeticity, contributing to the excellent reliability of the DAC729.