LMK3H0102: schematic question

Jeff YANG

Part Number: LMK3H0102
Other Parts Discussed in Thread: LMKDB1204,

Tool/software:

Hi,

I have a question regarding the LMK3H0102A015RERR EVB. I noticed that there is a PI filter circuit reserved on both VDD and VDDO power rails, as shown below.
However, I couldn’t find any specific mention of this in the datasheet.

Is it necessary to implement a PI filter on these rails? If yes, do you have any recommendations for the bead specifications?
Regarding the decoupling capacitors shown in the schematic below, is it acceptable to use 1 μF and 0.1 μF for VDD/VDDO?

Thanks!

Jeff

28 days ago

+1 Kadeem Samuel 28 days ago

TI__Mastermind 22210 points

Jeff,

The PI filtering is not strictly required, but rather is recommended for best phase noise performance. We use the Wurth Elektronik 742792656 ferrite beads.
No issue with the capacitor selection.

Thanks,

Kadeem

0 Jeff YANG 23 days ago in reply to Kadeem Samuel

Mastermind 7755 points

Hi Kadeem,

Got it, thank you!

0 Jeff YANG 11 days ago in reply to Jeff YANG

Mastermind 7755 points

Hi Kadeem,

I've update the PI filter and layout please help check it is fine. thanks!

MUX_CLKGEN_sch.pdf

0 Kadeem Samuel 11 days ago in reply to Jeff YANG

TI__Mastermind 22210 points

Jeff,

For the LMK3H0102, this looks good. I will re-assign our buffer experts to review the schematic and layout for the LMKDB1204.

Thanks,

Kadeem

0 Michael Srinivasan 11 days ago in reply to Kadeem Samuel

TI__Expert 8370 points

Jeff,

For the LMKDB1204, can you point out where the decoupling capacitors are? Typically, these need to be placed as close to the device as possible.

The only other thing I would suggest is to make sure the vias in your DAP are tented - your vias are placed in the areas where solder paste will be applied.

Thanks,

Michael

0 Jeff YANG 10 days ago in reply to Michael Srinivasan

Mastermind 7755 points

Hi Michael,

Please see below decoupling capacitors locatioin. Is it need to modify? thanks!

Jeff

+1 Michael Srinivasan 10 days ago in reply to Jeff YANG

TI__Expert 8370 points

Hi Jeff,

These all appear to be sufficiently close to the LMKDB1204. No modification seems necessary.

Thanks,

Michael

0 Jeff YANG 9 days ago in reply to Michael Srinivasan

Mastermind 7755 points

Hi Michael,

Got it, thank you!

Jeff

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LMK3H0102: schematic question