Complete Dual 18-bit 16 X Fs Audio Dac - Analog Devices

The AD1865 is a complete, dual 18-bit DAC offering excellent THD+N and SNR while requiring no external components. Two complete signal channels are included. This results in cophased voltage or current output signals and eliminates the need for output demultiplexing circuitry. The monolithic AD1865 chip includes CMOS Logic elements, bipolar and MOS linear ele- ments and laser-trimmed thin-film resistor elements, all fabri- cated on Analog Devices ABCMOS process. The DACs on the AD1865 chip employ a partially segmented architecture. The first four MSBs of each DAC are segmented into 15 elements. The 14 LSBs are produced using standard R-2R techniques. Segment and R-2R resistors are laser trimmed to pro- vide extremely low total harmonic distortion. This architecture minimizes errors at major code transitions resulting in low out- put glitch and eliminating the need for an external deglitcher. When used in the current output mode, the AD1865 provides two 1 mA output signals. Each channel is equipped with a high performance output am- plifier. These Amplifiers achieve fast settling and high slew rate, producing 3 V signals at load currents up to 8 mA. Each out- put Amplifier is short-circuit protected and CAN withstand indefi- nite short circuits to ground. The AD1865 was designed to balance two sets of opposing re- quirements, channel separation and DAC matching. High chan- nel separation is the result of careful layout. At the same time, both channels of the AD1865 have been designed to ensure matched gain and linearity as well as tracking over time and temperature. This assures optimum performance when used in stereo and multi-DAC per channel applications. By Analog Devices, Inc.