wccheng
Full Member level 5
Dear all,
I am design a up-mixer with variable gain in the Tx path. In the design, I use passive mixer architecture. It is quadrature input and differential output. Afterwards, the up-converted signal will enter the buffer with transformer loading and give out single ended output. The single ended output will connect with driving amplifier input. The problem is appeared. In the preliminary design, I just using 3pF as output loading in the design. After my colleague finished his DA design, I connect my upmixer and do the simulation. It is found that his loading is 5pF // 50ohms. It makes my upmixer gain drops so much even I have tuned back to the same frequency range. How could I fix the problem in order to get back the gain?
Thanks,
wccheng
I am design a up-mixer with variable gain in the Tx path. In the design, I use passive mixer architecture. It is quadrature input and differential output. Afterwards, the up-converted signal will enter the buffer with transformer loading and give out single ended output. The single ended output will connect with driving amplifier input. The problem is appeared. In the preliminary design, I just using 3pF as output loading in the design. After my colleague finished his DA design, I connect my upmixer and do the simulation. It is found that his loading is 5pF // 50ohms. It makes my upmixer gain drops so much even I have tuned back to the same frequency range. How could I fix the problem in order to get back the gain?
Thanks,
wccheng