Varicap (Varactor) Paralleling Madness
 

Hi everyone,

I'm working on an experiment where I want to investigate the nonlinear effects of a varicap (varactor). The problem is that I need the capacitance to be very large.... very very large.

I found a suitable varicap (BB640), having a capacitance ratio of about 25 times with a maximum capacitance of 30pF. For my experiment I need a maximum capacitance of ~100nF. My insane question is do you think it would be possible to parallel 4000 of these devices together and obtain a 100nF version of this particular device, with the same cap ratio change (25 for this particular model)?

These diodes will never be forward biased, but will only ever be reversed biased (so I don't think there will be any heating issues). I'm not really sure what to expect; if the total capacitance ratio will remain after 4000 parallels or if something else happens. I had hopes of trying to change the capacitance at a 1MHz rate (maximum), I'm not sure what the speed a single varicap can change at but I assume that 4000 will probably change a bit slower. I've spent many hours looking to see if anyone has done anything this extreme and the most I found was on this forum where someone discussed putting 2 in parallel.

Any insights would be most appreciated.