sthdmi002a STMicroelectronics, sthdmi002a Datasheet - Page 5

• Manufacturer Part Number: sthdmi002a
• Description: Wide Bandwidth, 2 To 1 Hdmi Switch With Single Enable
• Manufacturer: STMicroelectronics

2
2.1
2.2
STHDMI002A
Functional description
The STHDMI002A routes physical layer signals for high bandwidth digital video and is
compatible with low voltage differential signaling standards like TMDS. The device multiplexes
differential outputs from a video source to one of the two corresponding outputs to a common
display. The low on-resistance and low I/O capacitance of STHDMI002A result in a very small
propagation delay. The device integrates SPDT-type switches for 3 differential data TMDS
channels and 1 differential clock channel. Additionally it integrates the switches for DDC and
HPD lines switching.
The I²C interface of the selected input port is linked to the I²C interface of the output port, and
the hot plug detector (HPD) of the selected input port is output to HPD_SINK. For the unused
ports, the I²C interfaces are isolated, and the HPD pins are also isolated.
HPD pins
The input of the Y_HPD is 5V tolerant, allowing direct connection to 5V signals. The switch is
able to pass both 0V and 5V signal levels. The HPD switch resistance depends on the input
voltage level. At low (near to 0V) input voltage levels, the resistance is 20Ω typically and at high
(near to 5V) input voltage levels, the resistance is 150Ω typically.
DDC channels
The DDC channels are designed with a bi-directional NMOS gate, providing 5V signal
tolerance. The 5V tolerance allows direct connection to a standard I²C bus, thus eliminating the
need for a level shifter. When the input is a 5V, the NMOS switch is turned off and the pull up
resistor on either side of the switch determines the high voltage potential.
Functional description
5/26