EMRFD Message Archive 14392

Message Date From Subject
14392 2017-10-18 14:36:17 billdunsmore@att.... VCA810 RF derived AGC?

Hello, I am designing a superhet with a 9 MHz IF.  Only one major decision remains, the AGC. I can always build a Hycas, but I have noticed a number of relatively simple circuits using IC's these days. For example, the VCA810 and a high speed op amp will provide 60 db of AGC according to the data sheet.

Anyone have a comment on this circuit or could you recommend another ?

Thanks, Bill, ex-K4KIR

14393 2017-10-18 19:33:25 bwbangerter Re: VCA810 RF derived AGC?
Take a look at the data sheet for the AD603.  I have used this part in a circuit to level the output of an AD9850 DDS signal generator.  It can use a unipolar 10 v power supply, and has a voltage controlled gain (attenuator actually) over a wide range.  It appears to have some similarity to the TI part you mention.

Ben, K0IKR

14394 2017-10-19 14:22:21 Bill Dunsmore Re: VCA810 RF derived AGC?
Thanks for your post, Ben. I am also looking at the AD603.

Sent from Mail for Windows 10

14734 2018-05-03 08:38:11 drmail377 Re: VCA810 RF derived AGC?
I may have a working LTspice AD603 simulation kicking around here somewhere.