Datasheet

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VDD33
0.1 Fm
ToRX+
ToRX-
All-Plastic
(5or10metersmaximum)
(1)ToshibaTORX141orequivalent.
Optical
Receiver
(1)
(1)ToshibaTORX173,TORX176,TORX179,orequivalent.
+5V
SN74LVC1G125
orEquivalent
0.1mF
T RX+o
ToRX-
All-Plastic
(5or10metersmaximum)
Optical
Receiver
(1)
VDD33
5
2
3
1
4
SRC4382
SBFS030C – JANUARY 2006 – REVISED SEPTEMBER 2007
Optical interfaces utilizing all-plastic fiber are commonly employed for consumer audio equipment where
interconnections are less than 10m in length. Optical receiver modules utilized for a digital audio interface
operate from either a single +3.3V or +5V supply and have a TTL-, CMOS-, or low-voltage CMOS-compatible
logic output. Interfacing to +3.3V optical receivers is straightforward when the optical receiver supply is powered
from the SRC4382 VDD33 power source, as shown in Figure 85 . For the +5V optical receivers, the output high
logic level may exceed the SRC4382 line receiver absolute maximum input voltage. A level translator is required,
placed between the optical receiver output and the SRC4382 line receiver input. Figure 86 shows the
recommended input circuit when interfacing a +5V optical receiver to the SRC4382 line receiver inputs. The
Texas Instruments SN74LVC1G125 single buffer IC is operated from the same +3.3V supply used for SRC4382
VDD33 supply. This buffer includes a +5V tolerant digital input, and provides the logic level translation required
for the interface.
Figure 85. Interfacing to a +3.3V Optical Receiver Module
Figure 86. Interfacing to a +5V Optical Receiver Module
44 Submit Documentation Feedback Copyright © 2006 – 2007, Texas Instruments Incorporated
Product Folder Link(s): SRC4382