Re: Problems about LNA output design
时间：04-11
整理：3721RD
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Now I'm designing the output part of LNA and I found little literature focused the output design of LNA. The following are my questions:
1) The LNA will be connected to the next stage. How to include the next stage input impedance when I simulate LNA using SpectreRF?
2) I use the shunt peaking technique for output design. The gain will be gm*RL*Q. In the output part, C represents the whole capacitance including output capacitance of transistor, parasitics and next stage input capacitance. How can I decide the value of L and R?
Please help me. Thanks a lot!
Added after 4 hours 26 minutes:
Is there anyone who can help me?
Thanks!
1) The LNA will be connected to the next stage. How to include the next stage input impedance when I simulate LNA using SpectreRF?
2) I use the shunt peaking technique for output design. The gain will be gm*RL*Q. In the output part, C represents the whole capacitance including output capacitance of transistor, parasitics and next stage input capacitance. How can I decide the value of L and R?
Please help me. Thanks a lot!
Added after 4 hours 26 minutes:
Is there anyone who can help me?
Thanks!
L should shut resonant with c at fundmetal frequency and RL is equal to optimal output resistance. If the output power is PO, and drain voltage is VD, the RL=(VD-Vsat)^2/PO
Thank you very much.
If I want to include the next stage's input impendance, and L should resonate with the whole C , how can I set the output port using SpectreRF for simulation?