Datasheet

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APPLICATION INFORMATION
Supply Voltage
TMDS Inputs
TMDS Input Fail-Safe
V
CC
R
INT
R
INT
TMDS
Receiver
TMDS
Driver
R
T
R
T
Y
Z
A
B
AV
CC
TMDS341A
TMDS Outputs
TMDS341A
V
CC
GND
TMDS
Driver
AV
CC
Z
O
= R
T
Z
O
= R
T
R
T
R
T
TMDS
Receiver
TMDS341A
SLLS702B MAY 2006 REVISED MARCH 2007
All V
CC
pins can be tied to a single 3.3-V power source. A 0.01-µF capacitor is connected from each V
CC
pin
directly to ground to filter supply noise.
Standard TMDS terminations are integrated on all TMDS inputs. External terminations are not required. Each
input channel contains an 8-dB equalization circuit to compensate for cable losses. The voltage at the TMDS
input pins must be limited per the absolute maximum ratings. An unused input should not be connected to
ground as this would result in excessive current flow damaging the device.
TMDS input pins do not incorporate fail-safe circuits. An unused input channel can be externally biased to
prevent output oscillation. One pin can be left open with the other grounded through a 1-k resistor as shown in
Figure 34 .
Figure 34. TMDS Input Fail-Safe Recommendation
A 1% precision resister, 4.64-k , connected from VSADJ to ground is recommended to allow the differential
output swing to comply with TMDS signal levels. The differential output driver provides a typical 10-mA current
sink capability, which provides a typical 500-mV voltage drop across a 50- termination resistor.
Figure 35. TMDS Driver and Termination Circuit
As shown in Figure 35 , if V
CC
(TMDS341A supply) and AV
CC
(sink termination supply) are powered, the TMDS
output signals are high impedance when OE is high. Normal operation is with both supplies active.
Also shown in Figure 35 , if V
CC
is on and AV
CC
is off, the TMDS outputs source a typical 5-mA current through
each termination resistor to ground. The terminations consume a total of 10 mW of power independent of the
OE logical selection. When AV
CC
is powered on, normal operation ( OE controls output impedance) is resumed.
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