The AD7840 is a fast， complete 14-bit voltage output D/A converter. It consists of a 14-bit DAC， 3 V buried Zener reference， DAC output amplifier and high speed control logic. The part features double-buffered interface logic with a 14-bit input latch and 14-bit DAC latch. Data is loaded to the input latch in either of two modes， parallel or serial. This data is then transferred to the DAC latch under control of an asynchronous LDAC signal. A fast data setup time of 21 ns allows direct parallel interfacing to digital signal processors and high speed 16-bit microprocessors. In the serial mode， the maximum serial data clock rate can be as high as 6 MHz. The analog output from the AD7840 provides a bipolar output range of ±3 V. The AD7840 is fully specified for dynamic performance parameters such as signal-to-noise ratio and harmonic distortion as well as for traditional dc specifications. Full power output signals up to 20 kHz can be created. The AD7840 is fabricated in linear compatible CMOS （LC2 MOS）， an advanced， mixed technology process that combines precision bipolar circuits with low power CMOS logic. The part is available in a 24-pin plastic and hermetic dual-in-line package （DIP） and is also packaged in a 28-terminal plastic leaded chip carrier （PLCC）.