AD1866_15 Datasheet, PDF (9/12 Pages) Analog Devices – Single Supply Dual 16-Bit Audio DAC

Applications of the AD1866
APPLICATIONS OF THE AD1866
The AD1866 is a high performance audio DAC specifically de-
signed for portable and automotive digital audio applications.
These market segments have technical requirements fundamen-
tally different than those found in the high-end or home use
market segment. Portable equipment must rely on components
which require low amounts of power to offer reasonable play-
back times. Also, battery voltage tends to diminish as the end of
the discharge cycle is approached. The AD1866’s ability to op-
erate from a single +5 V supply makes it a good choice for bat-
tery operated gear. And, as the battery voltage drops, the power
dissipation of the AD1866 drops. This extends the usable bat-
tery life. Finally, as the battery supply voltage drops, the bias
voltages and signal swings also drop, preventing signal clipping
and abrupt degradation of distortion. Figure 3 illustrates how
the THD+N performance of the AD1866 remains constant
through a wide supply voltage range.
Automotive equipment relies on components which are able to
consistently perform over a wide range of temperatures. In addi-
tion, due to the limited space available in automotive applica-
tions, small size is essential. The AD1866 has guaranteed
operation between –35°C and +85°C, and the 16-pin DIP or
16-pin SOIC package is particularly attractive where overall size
is important.
Since the AD1866 provides dc bias voltages, the entire signal
chain can be dc coupled. This eliminates ac coupling capacitors
from the signal path, improving low frequency performance and
lowering system cost and size.
+5V POWER
SUPPLY
In summary, the AD1866 is an excellent choice for multimedia,
battery operated portable or automotive digital audio systems.
In the following sections, some examples of high performance
audio applications featuring the AD1866 are described.
AD1866 with the Sony CXD2550P Digital Filter
Figure 11 illustrates a 16-bit CD player design incorporating an
AD1866 DAC, a Sony CXD2550P digital filter, and 2-pole
antialias filters. This high performance, single supply design op-
erates at 8× F_S and is suitable for portable and automotive ap-
plications. In this design, the CXD2550P filter transmits left
and right channel digital data to the AD1866. The left and right
latch signals, LL and LR, are both provided by the word clock
signal (LRCKO) of the digital filter. The digital data is con-
verted to low distortion output voltages by the output amplifiers
on the AD1866. Also, no deglitching circuitry or external ad-
justments are required. Bypass capacitors, noise reduction
capacitors and the antialias filter details are omitted for clarity.
ADDITIONAL APPLICATIONS
In addition to CD player designs, the AD1866 is suited for
similar applications such as DAT, portable musical instruments,
laptop and notebook personal computers, and PC audio I/O
boards. The circuit techniques illustrated here are directly ap-
plicable in those applications. Figures 12, 13, 14, and 15 show
connection diagrams for the AD1866 and several popular digital
filter chips from NPC and Yamaha. Each application operates
at 8× F_S operation. Please refer to the appropriate sections of
this data sheet for additional information.
CXD2550P
1 TEST
SLOT 18
2
LRCKO ¹⁷
3
DATAL ¹⁶
4
DATAR 15
5 V_DD
6
7
8 _LRCK
V_SS 14
BCKO 13
V_SS 12
11
9
LATCH ¹⁰
AD1866
1 V_L
V_BL 16
NJM2100
2 LL
V_{S 15}
6.8kΩ ³³⁰
1
6.8kΩ
pF
+V_S 8
3 DL
V_OL 14
2
6.8kΩ
7
4 CLK
NRL 13 ^{1000 pF}
3
6
5 DR
AGND 12
4
5
6 LR
NRR 11
7 DGND
8 V_BR
V_OR 10
V_S 9
6.8kΩ
LEFT
CHANNEL
OUTPUT
330 pF
RIGHT
CHANNEL
OUTPUT
6.8kΩ
6.8kΩ
1000 pF
Figure 11. AD1866 with Sony CXD2550P Digital Filter
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