Low-cost 1 Watt RF power amplifier (in progress)

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Low-cost, 800mA RF power amplifier used for tabletop MRI scanners to drive small solenoid coils (~1cm diameter NMR sample tubes). This board uses the Motorola MHW592 RF amplifier module, which is obsolete, but available on eBay. The board runs on 24 Volts and includes a linear regulator and blanking circuit controlled by a gating signal from the spectrometer. The blanking cuts power to the RFPA quickly (for instance to eliminate unwanted RF noise during signal readout). There is an optional low-power first gain stage that can be bypassed with a jumper wire if it is not needed. The MHW592 power stage provides 35dB of gain with a 1dB compression point of 900mW.

The datasheet calls for 24V, but we have gotten away with running the MHW592 at 18V for convenience (with 24V power supply provided to the on-board regulator).

Datasheet for MHW592: https://datasheetspdf.com/pdf-file/1114767/Motorola/MHW592/1

Click here to download EAGLE board files (layout and schematic), GERBER files, and Bill of Materials.

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Board layout for MHW592 daughter board