CS8427-CSZR Cirrus Logic Inc, CS8427-CSZR Datasheet - Page 51

• Manufacturer Part Number: CS8427-CSZR
• Description: Audio DSPs IC 96 kHz Digital Audio Transceiver
• Manufacturer: Cirrus Logic Inc

Specifications of CS8427-CSZR

• Operating Temperature Range: - 10 C to + 70 C
• Mounting Style: SMD/SMT
• Package / Case: SOIC-28
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

18.3
The CS8427 AES3 receiver is designed to accept
both the professional and consumer interfaces.
The digital audio specifications for professional
use call for a balanced receiver, using XLR con-
nectors, with 110 Ω ±20% impedance. The XLR
connector on the receiver should have female pins
with a male shell. Since the receiver has a very
high input impedance, a 110 Ω resistor should be
placed across the receiver terminals to match the
line impedance, as shown in
transformers are not required by the AES, they are,
however, strongly recommended.
If some isolation is desired without the use of trans-
formers, a 0.01 μF capacitor should be placed in
series with each input pin (RXP and RXN) as
shown in
not used, high frequency energy could be coupled
into the receiver, causing degradation in analog
performance.
Figure 23
blocking capacitor (0.1 μF to 0.47 μF) in series
with the cable input. This improves the robustness
of the receiver, preventing the saturation of the
transformer, or any DC current flow, if a DC voltage
is present on the cable.
DS477F5
Twisted
110 Ω
Pair
Coax
75 Ω
AES3 Receiver External
Components
Figure 23. Professional Input Circuit
Figure
XLR
Figure 25. Consumer Input Circuit
and
1
RCA Phono
Figure 24
24. However, if a transformer is
* See Text
75 Ω
110 Ω
show an optional DC
0.01 F
Figure
0.01 F
0.01 F
0.01 F
μ
μ
μ
μ
23. Although
CS8427
RXP
RXN
CS8427
RXP
RXN
In the configuration of systems, it is important to
avoid ground loops and DC current flowing down
the shield of the cable that could result when boxes
with different ground potentials are connected.
Generally, it is good practice to ground the shield
to the chassis of the transmitting unit, and connect
the shield through a capacitor to chassis ground at
the receiver. However, in some cases it is advan-
tageous to have the ground of two boxes held to
the same potential, and the cable shield might be
depended upon to make that electrical connection.
Generally, it may be a good idea to provide the op-
tion of grounding or capacitively coupling the shield
to the chassis.
In the case of the consumer interface, the stan-
dards call for an unbalanced circuit having a re-
ceiver impedance of 75 Ω ±5%. The connector for
the consumer interface is an RCA phono socket.
The receiver circuit for the consumer interface is
shown in
The circuit shown in
external RS422 receivers, optical receivers or oth-
er TTL/CMOS logic outputs drive the CS8427 re-
ceiver section.
18.4
Please refer to the application note AN134: “AES
and SPDIF Recommended Transformers” for re-
sources on transformer selection
Figure 24. Transformerless Professional Input Circuit
Twisted
110 Ω
Pair
TTL/CMOS
Isolating Transformer Requirements
Figure 26. TTL/CMOS Input Circuit
Figure
XLR
1
Gate
25.
* See Text
110 Ω
Figure 26
0.01 F
0.01 F
μ
0.01 F
0.01 F
μ
may be used when
μ
μ
CS8427
RXP
RXN
CS8427
CS8427
RXP
RXN
51