Select HEMT or LDMOS for 10W PA?
I want to design a 10W power amp of a base station at 900M.
I found a HEMT PA and a LDMOS PA, and I am curious about at which PA I should select.
1st of all, mass production is the 1st priority.
Could you give some comments?
Thanks.
Sorry, the signal is GSM.
So, what's the difference between HEMT PA and LDMOS PA?
Usually HEMT have hight ft and better power capacity. GaN HEMT owns very high power disspation ability to achieve very high power.
Hi, Yalisenda,
Thank you very much.
Cheers,
Tony Liu
the LDMOS will probably be cheaper. the LDMOS has a very low output impedance, and large output shunt capacitance, which will limit the bandwidth it can be matched over. The GaN fet has a higher output impedance to begin with, and less shunt capacitance since the devices are physically smaller, so you can do higher frequency and bigger bandwidths.
Personally speaking, I think LDMOS size is smaller than GaN. Since GaN is usually used in high voltage and high current.
If you're doing something standard like a 900MHz basestation, then you should be able to find reference designs from device manufacturers. I would look at those first, then compare the costs of each design, including supervisory circuitry (especially for HEMTs with negative gate bias). Don't worry so much about the underlying technology unless you're doing something novel.
Hi, mtwieg,
Thanks.
Cheers,
Tony Liu
HEMT transistors are more linear compare to LDMOS, take this into account.They are also more reliable at higher temperatures.