Single Supply Dual 16-Bit Audio DAC

The AD1866 is a complete dual 16-bit DAC offering excellent performance while requiring a single +5 V power supply. It is fabricated on Analog Devices' ABCMOS wafer fabrication process. The monolithic chip includes CMOS Logic elements, bipolar and MOS linear elements and laser trimmed, thinfilm resistor elements. Careful design and layout techniques have resulted in low distortion, low noise, high channel separa tion and low power dissipation.
The DACs on the AD1866 chip employ a partially segmented architecture. The first three MSBs of each DAC are segmented into 7 elements. The 13 LSBs are produced using standard R-2R techniques. The segments and R-2R resistors are laser trimmed to provide extremely low total harmonic distortion. The AD1866 requires no deglitcher or trimming circuitry.
Each DAC is equipped with a high performance output Amplifier These Amplifiers achieve fast settling and high slew rate, producing 1 V signals at load currents up to 1 mA. The buffered output signal range is 1.5 V to 3.5 V. The 2.5 V reference voltages eliminate the need for "false ground" networks.
A versatile digital Interface allows the AD1866 to be directly connected to all digital Filter chips. Fast CMOS Logic elements allow for an input Clock rate of up to 16 MHz. This allows for operation at 2x, 4x, 8x, or 16x the sampling frequency (where FS = 44.1 kHz) for each channel. The digital input pins of the AD1866 are TTL and +5 V CMOS compatible.
The AD1866 operates on +5 V power supplies. The digital supply, VL, CAN be separated from the Analog supply, VS, for reduced digital feedthrough. Separate Analog and digital ground pins are also provided. In systems employing a single +5 volt power supply, VL and VS should be connected together. In battery operated systems, operation will continue even with reduced supply voltage. Typically, the AD1866 dissipates 50 mW.
The AD1866 is packaged in either a 16-pin plastic DIP or a 16-pin plastic SOIC package. Operation is guaranteed over the temperature range of -35C to +85C and over the voltage supply range of 4.75 V to 5.25 V.
By Analog Devices, Inc.