Dual Serial Input, Voltage Output DACs
Single +5 Volt Supply
Low Power –50 mW
115 dB Channel Separation
Operates at 8؋ Oversampling
16-Pin Plastic DIP or SOIC Package
PC Audio Add-In Boards
Portable CD and DAT Players
Automotive CD and DAT Players
Dual 16-Bit Audio DAC
FUNCTIONAL BLOCK DIAGRAM
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, thin-
film 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 ampli-
fier. These amplifiers achieve fast settling and high slew rate,
producing ± 1 V signals at load currents up to ± 1 mA. The buff-
ered 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 2×, 4×, 8×, or 16× 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 re-
duced 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 bat-
tery operated systems, operation will continue even with re-
duced 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 –35°C to +85°C and over the voltage
supply range of 4.75 V to 5.25 V.
1. Single supply operation @ +5 V.
2. 50 mW power dissipation.
3. THD+N is 0.005% (typical).
4. Signal-to-Noise Ratio is 95 dB (typical).
5. 115 dB channel separation (typical).
6. Compatible with all digital filter chips.
7. 16-pin DIP and 16-pin SOIC packages.
8. No deglitcher required.
9. No external adjustments required.
*Protected by U.S. Patent Nos: 3,961,326; 4,141,004; 4,349,811; 4,857,862;
and patents pending.
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
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