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Hi, thanks for your reply.
During the impedance transformation, the SAW filter actually has voltage gain, although it introduces 1dB power loss. The voltage gain can be calculated as:
Vout^2/200 = Vin^2/50*L => VG=1.7825 ~ 5dB
Obviously this gain will help with the noise figure. Agree...
Let's consider a 50 ohm to 200 ohm impedance transformation SAW filter, and it has the insertion loss of 1dB. If it is inserted between a 50 ohm antenna and a 200 ohm LNA, will it help with the chain noise figure, or the noise figure of SAW+LNA will be better than LNA alone (refer to...
simulate pss delay
I want to simulate the group delay of a switched capacitor filter, however, after running the PSS+PAC simulation, I could not use the "special function" in the calculator. So, is there any other method to calculate the group delay?
Thanks in advance,
Re: LNA matching
jecyhale -- You need to calculate the input impedance of your LNA core. If the input impedance is low and already matches to 50ohm (CG topology, for instance), you have to use the off-chip cap, coz it would too bulky to integrate it on chip.
Hope it helps,
Thank you very much for your replies, guys. I'm sorry that I did not elaborate my requirements.
That's absolutely right that LNA should have gain and low noise generally, but for some cases, for example, with large signals input, the LNA should be able to switch low gain mode for linearity...
Does anyone here has the experience of designing LNAs with negative gain like -10 ~ -20dB and keeping the input impedance matched at the same time?
OR do you have any suggestions or references?
Thanks in advance.
phase noise calculation cadence simulation
Thank you, Khouly, did you mean the following document?
There's nothing about the Ring oscillator phase noise simulation. My current issue on the phase noise simulation is that the...
Does anyone here have the experience of designing the on-chip 50ohm driver/buffer for cable connection with testing equipment? The requirement on the driver/buffer are: wide bandwidth, high linearity and driving capability.
Thank you in advance,
Yes, the bondwire could be one of the reasons introducing unstability, and it is easy to explain: at certain frequency, the souce impedance of the input transistor becomes capacitive, thus the real part of the input impedance of the LNA becomes negative correspondently. However...