AnsweredAssumed Answered

AD8348 with added baseband gain

Question asked by Rick@Ri on Jul 17, 2014
Latest reply on Apr 17, 2015 by Rick@Ri

I say you chaps...

ad8348etc.JPG

I've added two LNA (MAX2634 - sorry!) and active filters with gain at baseband. It's a tough one to keep stable!

A SPICE model for the AD8348 would have been nice, to check the bias. I have built it, it does work, -100dBm sensitivity at 250MHz. A re-layout needed for more stability to give even better sensitivity.

I've got the model for the AD8692, (I use the dual for best layout) so at least I got the active filter sorted first. A big C on IOFS and QOFS to slug the higher gain feedback loop.

Here's a crude model for the AD835. Got a better one?

 

*AD835 by Richard Mayo

.subckt AD835 1 2 3 4 5 6 7 8

BV1 VZ 0 V=V(Z1,0)

R2 Z1 4 1000

G1 VZ 5 value={(V(1,2)*V(8,7)+V(4))/33.33}

Rout 5 VZ 33.33

R1 3 6 1000

Cout 5 3 636p

.ends AD835

 

TTFN

     Richard.

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