a
FEATURES
120 dB Signal-to-Noise Ratio
102 dB D-Range Performance
1 dB Gain Linearity
1 mA Output Current
16-Pin DIP Package
0.0012% THD + N
APPLICATIONS
High Performance Compact Disc Players
Digital Audio Amplifiers
Synthesizer Keyboards
Digital Mixing Consoles
High Resolution Signal Processing
鈥揤
S
鈥揤
S
1
2
Ultralow Noise
20-Bit Audio DAC
AD1862*
FUNCTIONAL BLOCK DIAGRAM
VOLTAGE
REFERENCE
16 +V
S
15 NR
2
14 ADJ
13 NR
1
INPUT
&
DIGITAL
OFFSET
12 AGND
20-BIT
DAC
11 I
OUT
10 R
F
9
DGND
TRIM 3
+V
L
4
CLK 5
LE 6
DATA 7
鈥揤
L
8
AD1862
PRODUCT DESCRIPTION
The AD1862 is a monolithic 20-bit digital audio DAC. Each
device provides a 20-bit DAC, 20-bit serial-to-parallel input
register and voltage reference. The digital portion of the
AD1862 is fabricated with CMOS logic elements that are pro-
vided by Analog Devices鈥?BiMOS II process. The analog por-
tion of the AD1862 is fabricated with bipolar and MOS devices
as well as thin-film resistors.
New design, layout and packaging techniques all combine to
produce extremely high performance audio playback. The de-
sign of the AD1862 incorporates a digital offset circuit which
improves low-level distortion performance. Low stress packag-
ing techniques are used to minimize stress-induced parametric
shifts. Stress-sensitive circuit elements are located in die areas
which are least affected by packaging stress. Laser-trimming of
initial linearity error affords extremely low total harmonic
distortion. Output glitch is also small, contributing to the over-
all high level of performance.
The noise performance of the AD1862 is excellent. When used
with the recommended two external noise-reduction capacitors,
it achieves 120 dB signal-to-noise ratio.
The serial input port consists of the clock, data and latch enable
pins. A serial 20-bit, 2s complement data word is clocked into
the DAC, MSB first, by the external data clock. A latch-enable
signal transfers the input word from the internal serial input
register to the DAC input register. The data clock can function
at 17 MHz, allowing 16
脳
F
S
operation. The serial input port is
compatible with second-generation digital filter chips for con-
sumer audio products such as the NPC SM5813 and SM5818.
The AD1862 operates with
卤
5 V to
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12 V supplies for the dig-
ital power supplies and
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12 V supplies for the analog supplies.
The digital and analog supplies can be separated for reduced
digital crosstalk. Separate analog and digital common pins are
also provided. The AD1862 typically dissipates less than
300 mW.
The AD1862 is packaged in a 16-pin plastic DIP. The operating
range is guaranteed to be 鈥?5掳C to +70掳C.
PRODUCT HIGHLIGHTS
1. 120 dB signal-to-noise ratio. (typical)
2. 102 dB D-Range performance. (minimum)
3.
卤
1 dB gain linearity @ 鈥?0 dB amplitude.
4. 20-bit resolution provides 120 dB of dynamic range.
5. 16
脳
F
S
operation.
6. 0.0016% THD+N @ 0 dB signal amplitude. (typical)
7. Space saving 16-pin DIP package.
8.
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1 mA output current.
*Protected by U.S. Patent Numbers: 4,349,811; 4,857,862; 4,855,618;
3,961,326; 4,141,004; 4,902,959.
REV. A
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
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