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broadband or narrowband match in LNA (Read 2688 times)

baab Senior Member Offline Posts: 178 EA	broadband or narrowband match in LNA Dec 07^th, 2013, 11:26am Hi, I need your help again. If I design a LNA with bandwidth = 20MHz, what kind of matching that I need, broadband or narrowband match?
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aaron_do Senior Fellow Offline Posts: 1398	Re: broadband or narrowband match in LNA Reply #1 - Dec 7^th, 2013, 6:26pm Hi baab, It depends on the center frequency. For your 1.7 GHz center, 20 MHz is very very narrowband. You need to design your bandwidth so that it accounts for variation in the network's center frequency. Aaron
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baab

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Re: broadband or narrowband match in LNA
Reply #2 - Dec 7^th, 2013, 7:23pm

Hello Aaron,

Now I switched to fc = 1.555GHz. Based on your answer, I guess it is also narrowband, right?
Quote:

You need to design your bandwidth so that it accounts for variation in the network's center frequency.

May I know what cause the variation?
By the way, I am reading the book you recommended "The Design of CMOS Radio-Frequency Integrated Circuits" by Thomas H. Lee. It is much easier than Razavi book.

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aaron_do Senior Fellow Offline Posts: 1398	Re: broadband or narrowband match in LNA Reply #3 - Dec 8^th, 2013, 6:41pm For the LC tank, I suppose process and the accuracy of your modeling would be the biggest errors. Of course part of the LC tank would be made up of your transistor capacitances which are subject to voltage and temperature variation. Aaron
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