AK4115 Datasheet, PDF (31/64 Pages) Asahi Kasei Microsystems – High Feature 192kHz 24bit Digital Audio Interface Transceiver

ASAHI KASEI
[AK4115]
„ Bi-phase signal output circuit
The AK4115 includes two TX output buffers. The output level is proportional to TVDD voltage. The T1 in Figure 23,
Figure 24, Figure 25 and Figure 26 is a transformer of 1:1. The resistor values should use ±1% accuracy.
1. Line Driver of TX0
The output level of TX0 is 0.5V ± 20% using the external resistor network in consumer mode.
R1
TX0
R2
75Ω cable
TVSS
T1
Figure 23. TX0 External Resistor Network 1
TVDD
3.3V
3.0V
5.0V
R1
240Ω
220Ω
430Ω
R2
150Ω
150Ω
150Ω
Note: When the AK4115 is in the power-down mode (PDN pin = “L”), power supply current can be reduced by using an
AC coupling capacitor as shown in Figure 24, since TX1 output is undetermined in power-down mode.
0.1uF R1
TX0
TVSS
R2
75Ω cable
TVDD R1 R2
3.3V 240Ω 150Ω
T1
3.0V 220Ω 150Ω
5.0V 430Ω 150Ω
Figure 24. TX0 External Resistor Network 2
2. Line Driver of TX1
2-1. Professional Mode (TVDD = 4.5V ∼ 5.5V)
The TX1 has an RS422 line driver when TVDD is 5V±10%. The AES3 specification states that the line driver shall have
a balanced output with an internal impedance of 110 ohms ±20% and also requires a balanced output drive capability of 2
to 7 volts peak-to-peak into 110 ohm load. The internal impedance of the RS422 driver along with a series resistors of 75
ohms realizes this requirement.
TXP1
TXN1
75Ω
0.1uF
110Ω cable
T1
Figure 25. Professional Output Driver Circuit
MS0573-E-00
- 31 -
2006/12