Part Number: HMC659LC5, HMC460LC5, HMC981LP3E, HMC980LP4E
I'm planning to have these 2 amps and biasing ICs on my design. I need 60 dBc or better isolation between the amplifiers.
Are there any VDD biasing designs or parts that can achieve that?
I'm currently using Murata LQP series wirewound inductors as output chokes, but I can't get 60 dBc isolation between the amps.
Please help. Thanks.
We have not tested the RF leakage of HMC980 and HMC981 bias controller`s through their supply pins, but it should be better than 30 dBc at low frequencies. HArd to estimate at 10+ GHz. In order to help locating the issue, could you share the schematics and Rf leakage levels at the Vdd&Vdig pins of the bias controllers?
I could not find the insertion loss measurement for Murata LQP series, when the inductor is shunted on a thru line. If you can share the plot we can comment on typical isolation.
Conical inductors usually have 11 dB isolation around 10-20 GHz. And the bypass CAPs you add will also increase the isolation of the overall chain. adding additional LC filtering can also improve the isolation.
I have a few other questions with regards to HMC659+HMC920.
In AN1363 pg.15 and HMC920 datasheet pg 13, and HMC659 datasheet pg7, for pins 3 & 15, Vgg1 & Vgg2, the bypass cap values given by appnote and DS are different. I'd like to clarify what are the correct values to use.
For the HMC659 DS, also on pg7, there are 2 caps that are marked as tantalum caps. Is it OK to replace them with ceramic chip (X7R) caps?
For the HMC920, is it OK to change C2,3,7 to ceramic (X7R) caps? Why is high ESR needed on these pins?