I'm working on a LNA board to work in the 2.4GHz band. I'm using broadcom/avago MGA-635P8 amplifiers. Since I need more gain than a single stage can give me, I'm using 3 stages in cascade (although not truly in cascade, since there is a filter in between the first and following 2 stages, on a different board).

Since my board space is defined by the RF signal paths, I have a lot of board space left. I was wondering if it was a good idea to look at giving each of the LNAs its own local voltage regulator. Currently I'm using one voltage regulator to go from 6.5 to 5V, and then using this to go to the biasing networks of each of the chips (with a good amount of decoupling capacitance to try and avoid signal coupling through).

Will going to a multi-regulator offer any significant improvement, or is it not really necessary with modern IC's such at these "low" frequencies?


If cost isn't an issue, then multiple LDOs can improve their heatsinking, by spreading out the dissipation.

You may need to isolate stages for RF stability reasons. Don't think that separate LDOs give you much in the way of extra isolation at RF and microwave frequencies. It's series impedance, either small resistors, or better yet, ferrite beads between stages that help the decoupling caps do their job.


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