HDMI Switch. SiI9185A Datasheet
SiI9185A 3:1 HDMI Switch
Document # SiI-DB-1016-C01
SiI9185A 3:1 HDMI Switch
Silicon Image, Inc.
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© 2008-2010 Silicon Image, Inc. All rights reserved
ii © 2008-2010 Silicon Image, Inc. All rights reserved.
The SiI9185A 3:1 HDMI Switch is the first generation
of TMDS™ switching devices that supports the
features of revision 1.3 of the HDMI® Specification and
integrates the latest generation of TMDS core
technology. With three HDMI inputs and a single
output, the switch provides a low-cost method of
retransmitting protected digital audio and video and
adding additional HDMI ports to the latest digital TVs
(DTVs), giving consumers a truly all-digital experience.
New DTVs can easily connect to the many HDMI
sources coming to market, including DVDs, Set Top
Boxes (STBs), game consoles, PCs, camcorders, and
digital still cameras.
Unlike some other HDMI switching devices, which use
high-speed analog switches that can degrade TMDS
signals, the SiI9185A switch uses TMDS cores to
recover and retransmit the HDMI signal.
Backward compatibility with DVI 1.0 allows HDMI
systems to connect to any DVI 1.0 source.
The SiI9185A switch is the first generation of devices
from Silicon Image that integrates Extended Display
Identification Data (EDID). The EDID is stored in on-
board RAM downloaded from the system micro-
controller during power-up or initialization. The EDID
is reflected on each of the three HDMI ports through
the DDC bus. The device also allows using EDID
stored on an external ROM, and either location can be
selected for each port. Having the flexibility to provide
EDID content from on-board RAM can eliminate up to
three EDID ROMs and save board space.
This device provides additional features that eliminate
external components, lower system cost, and provide
enhanced features to the end-user. The switch provides
a complete solution for switching sink-side HDMI
signals, such as DDC switching and Hot Plug Detect
(HPD) control for each port, and 5-volt sense to speed
audio mute when changing HDMI cables. For source-
side applications, DDC switching can be bypassed
SiI9185A 3:1 HDMI Switch
with an external 4-channel I2C bus switch to allow
• The TMDS cores are capable of receiving and
transmitting at 2.25 Gbps.
• Video resolutions up to 1080p, 60 Hz, 12-bit or
720p/1080i, 120 Hz, 12-bit are supported.
• An adaptive equalizer provides long cable support,
even at Deep Color resolutions.
• The transmitter includes pre-emphasis.
• An integrated HDMI-compliant CEC I/O and the
Silicon Image CEC API eliminate the need for
additional external components.
• The API manages all CEC signaling using the CEC
protocol and makes CEC information available to
the system microcontroller, eliminating the
microcontroller overhead needed to manage the
CEC bus and thus simplifying design.
• The device can be controlled by the local I2C bus.
• An optional stand-alone mode (for which I2C
control is not required) is available for speeds up to
165 MHz and allows the device to act as a simple
• The CEC and EDID are still functional during the
very-low-power standby mode when the DTV is
off, which meets Energy Star and other power-
• 80-pin, 12 mm by 12 mm, 0.5 mm pitch, TQFP package
Figure 1. Typical Application
© 2008-2010 Silicon Image, Inc. All rights reserved.