Hello,
We are using RFMD RF6886 power amplifier in our application. We tested RF6886 for our application. But we got very less efficiency. Current consumption was very high. The gain was also not constant. Gain was constantly decreasing.
Operating Voltage : 3.3 V
Frequency: 437.025 MHz
Output Power: 1 Watt
Current : 1.92 A
Efficiency : 15.78 %
Input power fed to the HPA was swept from -20 dBm to 5 dBm. It was found that the gain was constantly decreasing. In the starting, at lower power, gain was about 33 dB. But as i/p power was increased the gain dropped to about 25 dB at output power of +30 dBm. The rated 1 dB compression point js at 34 dBm. So we weren't able to get 1 dB Compression point.
The schematic is used from the datasheet. The layout is exactly same as the evaluation board. We used the gerbers of evaluation board to make the layout. We have used thermal vias under the thermal pad for heat dissipation. But still temperature of the board rises in some time.
How could such low efficiency be explained? What could be the reason for constantly decreasing gain? And why is the current consumption so high?
It would be really very grateful if you could help us try find solution to this problem. Are there any methods to increase the efficiency and hence decrease the current consumption
