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Entry  Tue Mar 8 11:17:54 2011, Alastair, Laser, General, RF amplifiers 
    Reply  Wed Mar 9 09:31:50 2011, rana, Laser, Purchases, RF amplifiers : Cougars 
Message ID: 1344     Entry time: Tue Mar 8 11:17:54 2011     Reply to this: 1345
Author: Alastair 
Type: Laser 
Category: General 
Subject: RF amplifiers 

 I'm just about to order some cougar amplifiers.  There are some alternative ones that Frank pointed out on the minicircuits website:



These are 13dB amplifiers, and have a pretty flat noise figure down to lower frequencies.  The cougar spec sheet doesn't show the noise figure below about 50MHz, but it's already at 3dB and climbing exponentially, so the performance down around 33MHz where we readout is likely to be worse.  This is despite the part being sold as 10-1000MHz with 1.5dB noise figure.....  I guess you always need to look at the graphs.

Having said that, the cougar does significantly out perform the minicircuits part around 200MHz, where the noise figure really reaches ~1.5dB  (it is 3.2dB for the minicircuits amp), so for our transmission readout these are still significantly better.

The minicircuits part has the same package, and the same pin locations as the cougar but is a fraction of the cost ($50 instead of $173), and probably a fraction of the ordering hassle and wait time.  I'm going to go ahead and order 6 of the cougars, but we should also pick up at least a couple of these minicircuits amplifiers to see if they work better for our reflection locking (if needed given Zach's recent posts...)


There is also a further alternative, from RFbay, which we could add at the output if we bypass the socket for the cougar (it is in a minicircuits type of box).  This achieves ~0.7dB at higher frequencies (again this would work for our transmission readout if we really need to get better than 1.5dB from this part) and down at 33MHz it would be more like 1dB, which is still pretty impressive.


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