When Eudyna released the FMM5061 VF Power Amplifier MMIC , followed by DEMI making these devices available at a very reasonable price, I thought it would be a great addition to my transverter as this was a high gain device ( 26dB typical @ 10GHz). At the stage that I acquired the device, no commercially available boards were available, so I etched up my own complete with a regulated Vdd supply. I made provision for a MMIC amplifier driver stage with input and output attenuators IF required. The MMIC driver used is an NLB310 which has a gain of 9.5 dB @ 10 GHz and a Pout (@1dB comp) of +13dBm. As such only about +3-4 dBm drive is required for 3 W out. Most "Qualcomm" conversions and other low power transverter boards will supply this.
If I had waited a few months then I wouldn't have had to go through ALL the effort as Down East Microwave have provided a complete kit for this device. Nonetheless it was an enjoyable experience getting this board going from the ground up. I used Rogers 5880 teflon board and a pretty standard DC supply as seen on many of the microwave amplifiers published in DUBUS etc.... Nothing special about the supply and the Vdd regulator was setup so if the -ve voltage input "disappeared" the Vdd would be reduced to almost 0v.
The board is "sweat soldered" onto a copper spreader of 0.5mm to which the device is connected. this ensures a very "solid" ground path between the board and the device. In addition copper tabs are used on to the device flanges to ensure proper stability and performance. If these steps are taken in the grounding of the device and board it was found that the bypass caps on the device's Vdd and -Vgg were NOT needed.!!! In the end for "safety" I used 100pF and 10000pF caps on the Vdd and -Vgg lines.
A little "snow-flaking" was required to achieve Max gain and output and once this had been accomplished 5 W was seen in a "brief test " with Vdd =7V and Idd set for 2.2 A....I kept this test VERY Brief!
I now run the amp with the following parameters:
Vdd = 6.5
VId = 1.8 A
Input drive is set to produce 3W output ~ 10dBm into the device.
Many thanks to Jerry W7QX for his help in sorting out the bypass and grounding issues!
I can provide a high resolution scaled picture of the artwork if required, BUT Demi now have a Kit form available that makes it far more cost effective than trying to build this amp from scratch.
