Power supply requirement for output state of a high speed serial transmitter chip

Hi Guys,

I've this question. I'm using a HDMI converter chip which convert from another display format to HDMI.
For the core voltage which run at 1.2V , they specify quite a tight requirement on core power supply: 1.1-.13.
I plan to use a fast transient LDO for this power supply since it's going to power the core cput which would have plenty of logic circuit to do the display conversion.
My question is regarding the HDMI driver output(3.3V). This should be some kind of TMDS driver. The datasheet specify a tight tolerance on this 3.3V supply too (3.135- 3.465).
I plan to use a better accuracy part for this voltage. The question is whether we need to have fast transient power supply for this rail too. To me, this seem like an analog section and fast transient should not be a requirement but just require a good accuracy.

Thanks in advance for all the help.

Hi Kudjung,

using a fast precision LDO at is a good approach for the 1.2V core supply. Fast current demand requires also a good ceramic capacitor(low esr - https://www.illinoiscapacitor.com/pdf/Papers/low_ESR_fact_or_fiction.pdf ) near the package pin and most important are low inductance supply lines. The same applies to the 3.3V supply.

Enjoy your design work!