S
a
PCM Audio DACs
AD1851/AD1861
FUNCTIO NAL BLO CK D IAGRAM
FEATURES
110 dB SNR
Fast Settling Perm its 16؋
Oversam pling
؎3 V Output
Optional Trim Allow s Super-Linear Perform ance
؎5 V Operation
16-Pin Plastic DIP and SOIC Packages
Pin-Com patible w ith AD1856 & AD1860 Audio DACs
2s Com plem ent, Serial Input
–V
1
2
3
4
5
6
7
8
+V
S
16
15
S
LATCH
DAC
TRIM
DGND
SERIAL
INPUT
REGISTER
+V
L
14 MSB ADJ
NC
CLK
LE
I
I
13
12
11
OUT
OUT
AGND
SJ
CONTROL
LOGIC
APPLICATIONS
High-End Com pact Disc Players
Digital Audio Am plifiers
DAT Recorders and Players
Synthesizers and Keyboards
R
F
DATA
NC
10
9
AD1851/
AD1861
V
OUT
NC = NO CONNECT
P RO D UCT D ESCRIP TIO N
T he critical specifications of T HD+N and signal-to-noise ratio
are 100% tested for all devices.
T he AD1851/AD1861 is a monolithic PCM audio DAC. T he
AD1851 is a 16-bit device, while the AD1861 is an 18-bit de-
vice. Each device provides a voltage output amplifier, DAC,
serial-to-parallel register and voltage reference. T he digital por-
tion of the AD1851/AD1861 is fabricated with CMOS logic
elements that are provided by Analog Devices’ 2 µm ABCMOS
process. T he analog portion of the AD1851/AD1861 is fabri-
cated with bipolar and MOS devices as well as thin-film
resistors.
T he AD1851/AD1861 operates with ±5 V power supplies, mak-
ing it suitable for home use markets. T he digital supply, VL, can
be separated from the analog supplies, VS and –VS, for reduced
digital crosstalk. Separate analog and digital ground pins are
also provided. Power dissipation is 100 mW typical.
T he AD1851/AD1861 is available in either a 16-pin plastic DIP
or a 16-pin plastic SOIC package. Both packages incorporate
the industry standard pinout found on the AD1856 and
AD1860 PCM audio DACs. As a result, the AD1851/AD1861
is a drop-in replacement for designs where ±5 V supplies have
been used with the AD1856/AD1860. Operation is guaranteed
over the temperature range of –25°C to +70°C and over the
voltage supply range of ±4.75 V to ±5.25 V.
T his combination of circuit elements, as well as careful design
and layout techniques, results in high performance audio play-
back. Laser-trimming of the linearity error affords low total har-
monic distortion. An optional linearity trim pin is provided to
allow residual differential linearity error at midscale to be elimi-
nated. T his feature is particularly valuable for low distortion
reproductions of low amplitude signals. Output glitch is also
small, contributing to the overall high level of performance. T he
output amplifier achieves fast settling and high slew rates, pro-
viding a full ±3 V signal at load currents up to 8 mA. When
used in current output mode, the AD1851/AD1861 provides a
±1 mA output signal. T he output amplifier is short circuit
protected and can withstand indefinite shorts to ground.
P RO D UCT H IGH LIGH TS
l. AD1851 16-bit resolution provides 96 dB dynamic range.
AD1861 18-bit resolution provides 108 dB dynamic range.
2. No external components are required.
3. Operates with ±5 V supplies.
4. Space saving 16-pin SOIC and plastic DIP packages.
5. 100 mW power dissipation.
T he serial input interface consists of the clock, data and latch
enable pins. T he serial 2s complement data word is clocked into
the DAC, MSB first, by the external clock. T he latch enable
signal transfers the input word from the internal serial input
register to the parallel DAC input register. T he AD1851 input
clock can support a 12.5 MHz data rate, while the AD1861 in-
put clock can support a 13.5 MHz data rate. T his serial input
port is compatible with second generation digital filter chips
used in consumer audio products. T hese filters operate at over-
sampling rates of 2ϫ, 4ϫ, 8ϫ and 16ϫ sampling frequencies.
6. High input clock data rates and 1.5 µs settling time permits
2ϫ, 4ϫ, 8ϫ and 16ϫ oversampling.
7. ±3 V or ±1 mA output capability.
8. T HD + Noise and SNR are 100% tested.
9. Pin-compatible with AD1856 & AD1860 PCM audio DACs.
REV. A
Inform ation furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assum ed by Analog Devices for its
use, nor for any infringem ents of patents or other rights of third parties
which m ay result from its use. No license is granted by im plication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norw ood, MA 02062-9106, U.S.A.
Tel: 617/ 329-4700
Fax: 617/ 326-8703