THS4551: Bead for power supply of THS4551

Hello Xiaoquang,

   I would recommend pi-filter over LC filter using ferrite beads for digital power. Is this a shared digital/analog power between the two devices? Here is an in-depth app note on eliminating power supply noise throughout PCB design. I would recommend following layout guidelines in the THS4551 datasheet which is located under section 12, pages 57-60.

Thank you,

Sima 

Is this a shared digital/analog power between the two devices? --> THS4551 power supply, FPGA and eMMC are connecting to one power supply +3.3V.

So, should I place a bead for in front of THS4551 power supply to isolate from FPGA/eMMC?

Hey Kai, I am always interested in parts you suggest, that ferrite is nice, but kind of more like a power ferrite - fairly large, but low DC Z at higher currents. I was looking for a sim file, did not find that, but Mouser lists some alternates, here

Looking in my files for ferrite supply designs, here is one using Murata ferrite and Johannson X2Y cap at the DUT supply pins, 

And then I found another one where apparently Murata was providing a macro for the ferrite, open it as a macro file to see the innards. 

Ferrite and C test with R.TSC

And Sima, we tend to use ferrites over just L's as they have a more lossy R at higher F - this gives lower self resonance spikes in the impedances and transfer functions. 

Why need one for FPGA? I think it may be bad if look at TI app note. General hardware design/BGA PCB design/BGA (ti.com)

Hi Michael,

data on this 0603 ferrite bead can be found here:

https://ds.yuden.co.jp/TYCOMPAS/eu/detail?pn=FBMH1608HM601-T++&u=M

Kai