CS8415A-IZ CIRRUS [Cirrus Logic], CS8415A-IZ Datasheet - Page 36

• Manufacturer Part Number: CS8415A-IZ
• Description: 96 kHz DIGITAL AUDIO INTERFACE RECEIVER
• Manufacturer: CIRRUS [Cirrus Logic]

14. APPENDIX A: EXTERNAL
14.1
The CS8415A 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 Figure 10. Although
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 (RXP0 and RXN0) as
shown in Figure 11. However, if a transformer is
not used, high frequency energy could be coupled
into the receiver, causing degradation in analog
performance.
Figures 10 and 11 show an optional DC blocking
capacitor (0.1 µF to 0.47 µF) in series with the ca-
ble input. This improves the robustness of the re-
ceiver,
transformer, or any DC current flow, if a DC voltage
is present on the cable.
36
Twisted
AES3/SPDIF/IEC60958 RECEIVER
COMPONENTS
110 Ω
Pair
AES3 Receiver External
Components
Figure 10. Professional Input Circuit
preventing
XLR
1
* See Text
the
110 Ω
saturation
CS8415A
RXP0
RXN0
of
the
Twisted
Figure 11. Transformerless Professional Input Circuit
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 Figure 12. Figure 13 shows an imple-
mentation of the Input S/PDIF Multiplexer using the
consumer interface.
The circuit shown in Figure 14 may be used when
external RS422 receivers, optical receivers or oth-
er TTL/CMOS logic outputs drive the CS8415A re-
ceiver section.
14.2
Please refer to the application note AN134: AES
and SPDIF Recommended Transformers for re-
sources on transformer selection.
110 Ω
Pair
XLR
Isolating Transformer Requirements
1
* See Text
110 Ω
0.01 F
0.01 F
µ
µ
CS8415A
CS8415A
RXP0
RXN0