Australian Amateur Radio Station
|3 Watt + 10 GHz Amplifer
Utilising the FMM5061
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 oth 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
I now run the amp with the following parameters:
Vdd = 6.5 V
Id = 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 res 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
+12 V Vin
-5V In (externally
adjusted to set
RF In ~ 0dBm
Adjustable Vdd regulator
NLB 310 "driver"
RF out 3W
100pF 10000 pF Chip caps
for bypassing and 4.7 uF Tantalum
can be seen on VGG and VDD lines
Amplier rests on a Heat
sink and is incorporated
into 10 GHz Transverter