Datasheet

MAX3816A
I
2
C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
12 ______________________________________________________________________________________
Figure 5. Typical In-Display Application Circuit
DRVR_EN
V
CC
CLOCK_C
DATA_C
GND_REF
CLOCK_D
V
SS
DATA_D
V
DD
I
2
C SCL
I
2
C SDA
DISPLAY 3.3V
DISPLAY I
2
C BUS
REFERENCE TO 3.3V
47kΩ 47kΩ 2.2kΩ 2.2kΩ
10μF
10μF
GROUND PLANE
V
DD
1μF
LONG CABLE FROM VIDEO SOURCE:
DVI, HDMI, OR M1 CONNECTOR
CABLE UP TO 60m (200ft)
V
CC
DISPLAY GND
DDC SCL
DDC SDA
DDC +5V
SHIELD GNDS
DDC GND
DISPLAY CIRCUIT BOARD
V
DD
OR V
SS
(SEE DESCRIPTION)
MODE
V
SS
MAX3816A
Applications Information
Use Single MAX3816A at Display Side
A single MAX3816A is designed to achieve full
100kbps operation over 60m (200ft) of cable.
In-Display Application, Series Mode
When inserted at the front-end of a display, the source
side of the MAX3816A should be powered by the
source V
CC
(typically 5V) and ground (GND_REF). The
display-side V
DD
should be powered by the local dis-
play supply (typically 3.3V) to level-shift and diminish
the effects of supply noise and offset between source
and display (Figure 5). Supply decoupling capacitors of
at least 10µF should be connected close to the
MAX3816A between GND_REF and V
SS
, as well as
between GND_REF and V
CC
.
MAX3816A In-Display, Series Mode Advantages
(See Figure 5)
• Long cable reach.
• The MAX3816A acts as a buffer between source and
display. Hence, source reflections are isolated to the
source side of the MAX3816A, protecting display cir-
cuits from reflections (stair-step waveforms).
• The MAX3816A can be turned off (DRVR_EN assert-
ed low) to isolate source and display buses. The dis-
play bus can then operate independently of
source-cable loading or malfunctions.
• Multiple MAX3816As can be used in parallel as an
input mux to display, with only one “on” at a time.
Consideration
When using the level-shifter feature, as shown, and assum-
ing the display 3.3V supply is off when the display is off,
the Display EDID Prom will not be able to communicate to
source DDC. If required, the solution is to either place a 5V
EDID Prom on the source side of the MAX3816A or derive
the 3.3V V
DD
from the DDC +5V supply.