HMC566LP4E K-Factor

I can take a closer look at this but before I do, are you aware of the recently released ADL8142 which is an LNA that works from 23 to 31 GHz. (www.analog.com/adl8142) - Eamon

It's designed for satcom applications and will have a CSL grade. 

Hello Eamon,

thank you for the reply.

Yes I'll probably use ADL8142 in future, that seems far superior.

But know I've to fix this, so I don't need to trash three boards and the rest of precious components.

The only difference with the EVB is that I didn't use coplanar traces, but simple microstrips. This shouldn't make so much difference since in 10mil RO4350 the main propagation mode is microstrip either way. But the S2P parameters are from official EVK, so that remains a general point of instability for everyone.

Hi Partech,

                   The S-Parameter file on the web has the board de-embedded. S-Parameters of the part without de-embedding evaluation board show the part as stable.

Th red trace is the web file and blue trace is the part mounted on the evaluation board.

I think the board really needs to be Grounded Coplanar Waveguide at these frequencies.

Regards,

Jim B

Hello Jim,

Thank you very much for the clarification.

Yes, this basically confirms that the chip itself is prone to instability @39GHz and requires careful trace design. I think that this should be noted in next datasheet rev, since the current version specify the impedance only and the graphs are limited to 38GHz.

Thank you

Best regards

-Federico