3.3V and 5V connection for HDMI interface

Can anyone help me further with information about HDMI interface. According to the standards and documents I find on the internet the circuits at the receiver end are connected to a 3.3V power supply. However, there is no 3.3V supply line running through the cable. A 5V cable line is available though. Is this 5V supplied by the transmitter (can be small appliance even cell phone) or does the receiver (typical TV) need to provide this?

We are asked by our customer to provide HDMI interface on the ASIC we are developping and I'm puzzled with this 3.3V vs 5V connection. Do I need to create IO's that can tolerate 5V for all of the TMDS channels or only for some of the IO's?

Since we are working in advanced node (65nm or 40nm still undecided) the 5V tolerant IO is not available in the IO library from our foundry. We have experience developpîng 3.3V interfaces but have no previous info on the 5V applications.

Looking for explanations and possible partner for HDMI IO's for both receiver as well as transmitter. Thanks for your time!!!

Re: HDMI interface

You will need to use an interface IC.

For ESD and for level shifting.

Have a look at IC from California Micro Devices available from Mouser to meet HDMI spec.

:F

Re: HDMI interface

Thanks Frosty.

I could easily trace such a datasheet from CMD
**broken link removed**
That is helping me a lot already for better understanding the 5V and other issues.

Is that (adding separate level shifter IC) a general practice for HDMI? Because our customer asked us specifically for a single chip solution to save on board space and Bill-of-Material. This means that we will need to include level shifter and ESD on the chip. I'm afraid that the standard transistors in this advanced process will not be able to withstand the 5V.

Any idea on cost of such external level shifter?

Thanks,

Ted

Re: HDMI interface

You can get cost from Mouser from general idea.

Remember the HDMI spec ask you be able to drive I2C and CEC over a long cable so it is not just level shift and ESD.

So far I have not seen any true single chip solution, even on existing multimedia devices due to the low voltage cores. I think you already relaise the constraints now.

:F

Re: HDMI interface

Thanks Frosty! I will need to digg a little deeper into all the constraints!