The degree of attenuation across the DAC is determined by an 8-bit word applied to the on-board decode logic. This 8-bit word is decoded into a 17-bit word which is then applied to a 17-bit R-2R ladder. The very fine step resolution, which is available over the entire dynamic range, is due to the use of this 17-bit DAC. The AD7111/AD7111A are easily interfaced to a standard 8-bit MPU bus via an 8-bit data port and standard microprocessor control lines. The AD7111 WR input is edge triggered and requires a rising edge to load new data to the DAC. The AD7111A WR is level triggered to allow transparent operation of the latches, if required. It should also be noted that the AD7111A is exactly pin and function-compatible with the AD7524, an industry standard 8-bit multiplying DAC. This allows an easy upgrading of existing AD7524 designs which would benefit both from the wider dynamic range and the finer step resolution offered by the AD7111A.
The AD7111/AD7111A are fabricated in Linear Compatible CMOS (LC2MOS), an advanced, mixed technology process that combines precision bipolar circuits with lower CMOS logic.
