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bcdeepak
Joined: 28 Jul 2006
Posts: 88
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 12 May 2008 7:43 LNA post layout |
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i designed an inductively degenerated LNA for single frequency...ckt simulation is fine..i drew its layout...DRC,LVS are fine..but post layout is too bad
the input impedance is only 2 ohm...instead of 50ohm...what should i do?? plz help me
deepak
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jecyhale
Joined: 19 Feb 2008
Posts: 432
Helped: 46
Location: China
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| 12 May 2008 10:09 Re: LNA post layout |
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The problem will be caused by the post layout modeling file.
And you'd better connect the foundry to verify.
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rillyxue
Joined: 03 Jan 2007
Posts: 27
Helped: 1
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| 14 May 2008 3:52 Re: LNA post layout |
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| please check the Q of the input match network. and check if the peak frequency is varify from the wanted frequency.
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aomeen
Joined: 08 Dec 2005
Posts: 106
Helped: 18
Location: Egypt
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| 14 May 2008 16:38 Re: LNA post layout |
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Try to locate wither it's a Layout problem or parasitic modeling problem...
For example, run the extraction for the inductor alone, and check wither Q and L are equal to that given from schematic. repeat for other elements "RF transistor, Capacitors, etc."
It's possible also that you have double counted parasitics. "parasitics included in the RF models are re-extracted by the extraction tool..." I has similar experience with calibre once...
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bcdeepak
Joined: 28 Jul 2006
Posts: 88
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| 14 May 2008 18:24 Re: LNA post layout |
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hi
thanks for your reply
my output matching S22 is fine...but input matching S11 is too bad..is this the inductor problem???
i am using the inductors provided by UMC.
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