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13cm pre looks good


Robin Szemeti - G1YFG
 

Managed to find a bit of time to drop the SAV541 into the 13cm preamp board and run it up.

Looks good so far ... DC it is spot on, the auto-bias scheme resulted in 3V Vds and 60mA Id exactly as planned, the gain looks good and the gain roll-off is exactly where it was predicted.

Just needs a look up the input with the analyser tomorrow to confirm the input match is where I planned it and I'll make an attempt at a noise figure measurement ...

The only screw-up was the pinout on the PNP transistor pair used for the current mirror in the bias ... it was swapped left-right doh!  Easily sorted on the test board, just flip the device over and bend the legs ..  I must have made a mistake when creating the symbol from the datasheet ... I went back to PCB symbols to put the error right for version 1.1 and ... it was a mistake in the symbol downloaded from a commercial symbol library!! .. When you want something done right, do it yourself!

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Best regards,

Robin Szemeti

Redpoint Consulting Limited

E: robin@...
T: +44 (0) 1299 405028
M: +44 (0) 7971 883371

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Robin Szemeti - G1YFG