Amplifier Design Refinements

When I develop a project I like to complete a portion and then savor the moment by doing other related tasks. Yesterday was such a day when I revisited the packaging requirements for the amp. I decided to change the amplifier length to make it symmetrical. Although only a 1.25 inch increase, there is now a balance. It also gave me the room to add a binary step pi-network adaptor on the input of the amp. This adaptor will allow the controller to adjust the RF input to match the drive conditions (0–15dB is 1dB steps).

The amp module will monitored for RF Input, temperature of each device, current, automated bias current adjustment. The amp is SPI controlled through a 16–pin flat cable and would possibly be great in a SDR spinoff application. See the attached schematic.


From left to right: top, bottom, ground plane, inner routing layer

The layout is from bottom to top with an unbroken ground plane and three routing layers. The surface mount components are all located on the bottom.

The next step is further review and when I am able, to purchase a prototype circuit board and have fabricated a thermal block for heat transfer.

Thanks for your support and I look forward to adding your call to our list of builders. send an email to . You will be contacted when we are ready to begin the build.

73 K5OOR –  Virgil

HF Projects








File Attachment: HF SuperPacker Pro 100W Amp V3 Schematic.pdf (27 KB)



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