MAX3845UCQ+TD Maxim Integrated Products, MAX3845UCQ+TD Datasheet - Page 10

• Manufacturer Part Number: MAX3845UCQ+TD
• Description: IC SW/CBL DRVR DVI/HDMI 100TQFP
• Manufacturer: Maxim Integrated Products
• Type: HDMI/DVI Switchr

Specifications of MAX3845UCQ+TD

• Applications: HDMI, DVI, Receivers
• Mounting Type: Surface Mount
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DVI/HDMI 2:4 TMDS Fanout Switch and
Cable Driver
Back termination greatly reduces signal degradation
caused by reflections coming off DVI/HDMI connectors
and any other transmission line discontinuities. Much of
the reflected energy off a DVI connector, for example,
is absorbed by the back termination resistance rather
than reflected forward, causing eye closure. For the
cases shown in Figures 2 and 3, the return loss is
approximately 9.5dB. In other words, about 90% of the
reflected energy is absorbed by the back termination
resistors. Maxim strongly recommends using back ter-
mination to maximize the MAX3845’s performance.
Figure 2. DC-Coupled Differential Back Termination
Figure 3. AC-Coupled Single-Ended Back Termination
10
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*BACK TERMINATION RESISTORS ARE LOCATED AS CLOSE AS POSSIBLE TO THE MAX3845.
*BACK TERMINATION RESISTOR IS LOCATED AS CLOSE AS POSSIBLE TO THE MAX3845.
MAX3845
MAX3845
OUTPUT
TMDS
PAIR
OUTPUT
TMDS
100Ω*
PAIR
200Ω*
300Ω*
100Ω*
+3.3V
OR
0.1μF
0.1μF
The differential back termination options reduce the
common-mode output voltage seen by the TMDS
receiver to approximately V
The single-ended back termination option allows for
AC-coupling between the MAX3845 and a TMDS
receiver, so long as the TMDS receiver is tolerant of an
input common-mode voltage equal to V
later).
Z
0(DIFF)
= 100
Z
0(DIFF)
= 100
+3.3V
50Ω
RECEIVER
TMDS
+3.3V
50Ω
50Ω
CC
RECEIVER
Rx
TMDS
- 350mV (Table 1).
50Ω
Rx
CC
(HDMI 1.2 or