CS8427-CSZ Cirrus Logic Inc, CS8427-CSZ Datasheet - Page 50

• Manufacturer Part Number: CS8427-CSZ
• Description: IC TXRX DGTL AUDIO 96KHZ 28SOIC
• Manufacturer: Cirrus Logic Inc
• Type: Digital Audio Interface Transceiver (DIX)r

Specifications of CS8427-CSZ

• Applications: Automotive Audio
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC
• Audio Control Type: Digital
• Control Interface: I2C, Serial
• Control / Process Application: AV & DVD Receivers, CD-R, Digital Mixing Consoles
• Supply Voltage Range: 2.85V To 5.5V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 598-1783 - EVALUATION BOARD FOR CS8427
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 598-1733

18. APPENDIX A: EXTERNAL
This section details the external components re-
quired to interface the AES3 transmitter and re-
ceiver to cables and fiber-optic components.
18.1
The output drivers on the CS8427 are designed to
drive both the professional and consumer interfac-
es. The AES3 specification for professional/broad-
cast use calls for a 110 Ω source impedance and a
balanced drive capability. Since the transmitter
output impedance is very low, a 110 Ω resistor
should be placed in series with one of the transmit
pins. The specifications call for a balanced output
drive of 2-7 V peak-to-peak into a 110 Ω load with
no cable attached. Using the circuit in
the output of the transformer is short-circuit pro-
tected, has the proper source impedance, and pro-
vides a 5 V peak-to-peak signal into a 110 Ω load.
Lastly, the two output pins should be attached to
an XLR connector with male pins and a female
shell, and with pin 1 of the connector grounded.
50
CS8427
AES3/SPDIF/IEC60958 TRANSMITTER
AND RECEIVER COMPONENTS
AES3 Transmitter External
Components
Figure 20. Professional Output Circuit
TXN
TXP
110-(R
TXP
+R
TXN
)
CS8427
Figure 22. TTL/CMOS Output Circuit
TXN
TXP
Figure
1
XLR
20,
In the case of consumer use, the IEC60958 speci-
fications call for an unbalanced drive circuit with an
output impedance of 75 Ω and a output drive level
of 0.5 V peak-to-peak ±20% when measured
across a 75 Ω load using no cable. The circuit
shown in Figure 21 only uses the TXP pin and pro-
vides the proper output impedance and drive level
using standard 1% resistors. If VL+ is driven from
+3.3 V, use resistor values of 243 Ω and 107 Ω.
The connector for a consumer application would
be an RCA phono socket. This circuit is also short
circuit protected.
The TXP pin may be used to drive TTL or CMOS
gates as shown in Figure 22. This circuit may be
used for optical connectors for digital audio since
they usually have TTL or CMOS compatible inputs.
This circuit is also useful when driving multiple dig-
ital audio outputs since RS422 line drivers have
TTL compatible inputs.
18.2
Please refer to the application note AN134: AES
and SPDIF Recommended Transformers for re-
sources on transformer selection.
CS8427
Isolating Transformer Requirements
TXN
TXP
Figure 21. Consumer Output Circuit
TTL or
CMOS Gate
90.9 Ω
374-R
TXP
CS8427
DS477F5
RCA
Phono