CMOS LNA by Razavi

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CMOS LNA by Razavi

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Puppet1

Joined: 07 May 2004
Posts: 881
Helped: 2

17 Oct 2004 0:31 CMOS LNA by Razavi

Hello

I am reading Behzad Razavi's paper on "CMOS RF Receiver Design for Wireless LAN Application" I think from 1999's IEEE CICC.

He has an cascode LNA in CMOS, degenerated with an inductor and has an LC tank. Above the tank he has a diode connected NMOS acting as a bias I assume (I am not sure please clarify).

In another earlier paper of his, in 1997 (Symposium on VLSI Circuits) he biased the LNA with a resistor conencted to a diode connected transistor and a current source at the gate.

What are the advantages and disadvantages of the two schemes ?

I have never seen a CMOS LNA biased with diode connected NMOS before.

Thanks

thcm

Joined: 13 Jun 2004
Posts: 55
Helped: 3

19 Oct 2004 14:17 CMOS LNA by Razavi

Hi,Puppet1,Can you upload the schematic first?

cetc1525

Joined: 08 Oct 2004
Posts: 177
Helped: 3

24 Oct 2004 7:14 CMOS LNA by Razavi

does it use for voltage level shifting

Puppet1

Joined: 07 May 2004
Posts: 881
Helped: 2

28 Oct 2004 15:41 Re: CMOS LNA by Razavi

here it the circuit

look at M3, what is it's purpose ?

Sorry, but you need login in to view this attachment

nathan

Joined: 17 May 2001
Posts: 307
Helped: 2

28 Oct 2004 16:38 Re: CMOS LNA by Razavi

It provides with the correct common mode voltage to the mixer input.

nathan

Puppet1

Joined: 07 May 2004
Posts: 881
Helped: 2

29 Oct 2004 15:08 Re: CMOS LNA by Razavi

and what would that voltage be relative to VDD ?

And is it be using as a bias for the LNA too ?

iransatforum

Joined: 04 May 2004
Posts: 165
Helped: 9
Location: Sorrow-Land

29 Oct 2004 17:26 CMOS LNA by Razavi

find more info :

h**p://www.ee.ucla.edu/faculty/bios/razavi.htm

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