Problem during simulating active inductor with ADS simulator

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noor84

noor84

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Dear Friends,
I am designing Simple active inductor as in the pic1 (in the attachments)
My circuit problem is:
when I biasing DC for 50 uA and simulate it, all are ok (the current in Drain 1 and 2 is alright 50uA and the voltages).
But when I connect the term(Term1) with (50 Ohm) and simulate to measure (L and Q) the current drop to 7 mA and the voltages changes.
My question:
is it Ok for changes of voltages and currents?
The term1 will affect the value of inductance and quality factor when the current drop?
Please, see the pics in the attachments files.

1.jpg
2.jpg
 

 

is it Ok for changes of voltages and currents?
Click to expand...
It's not Ok if you want to keep the active inductor function. In case of doubt use AC coupling for the connected external circuit.
 

FvM said:
It's not Ok if you want to keep the active inductor function. In case of doubt use AC coupling for the connected external circuit.
Click to expand...

Thanks for reply.
I have to design and simulate active inductor and the currnt should be 50uA.
But when I connect The term1 to get S-parameters to get the (L) and (Q) From Z11.
The currents(Id1)at (Transistor1) and voltages changes.
Please,how can I simulate without change?
How can I connect(AC coupling for the connected external circuit).?
Did you mean I should remove term1?
If I did that.
How can I measure L and Q Without Term1?
 

AC coupling is usually performed by a sufficient large series capacitor.
 

FvM said:
AC coupling is usually performed by a sufficient large series capacitor.
Click to expand...

I connect (DC_Block1) founded in the ADS.
Is this connection is right? (When I simulated I see all currents and voltages are right as I calculated theoretically)
Please see the pic.

 

FvM said:
Yes, DC block is perfect.
Click to expand...

Many thanks for your help.

Please, I have to measure (Cgs1 and Cgs2) using the simulator (ADS) but as shown in the pic below, there is no value for Cgs!!
One thing also, how can I measure the operating frequency(F0) of the inductor? and Q?
I mean, when I calculated the frequency theoretically(F0=sqrt((gm1*gm2)/(Cgs1*Cgs2))) I get (F0=1.67GHz), how can I see it on data simulation?

 

Why BULK Pins are not connected ?? They should be connected to SOURCE or lower potential (GND)
 

BigBoss said:
Why BULK Pins are not connected ?? They should be connected to SOURCE or lower potential (GND)
Click to expand...

Hi BigBoss,
The second step of the design I will connect the bulk,
But now I am I have to learn how to measure (Cgs1 and Cgs2) using the simulator (ADS) but as shown in the pic below, there is no value for Cgs!!
One thing also, how can I measure the operating frequency(F0) of the inductor? and Q?
I mean, when I calculated the frequency theoretically(F0=sqrt((gm1*gm2)/(Cgs1*Cgs2))) I get (F0=1.67GHz), how can I see it on data simulation?

 

there is no value for Cgs
Click to expand...
Looks like the two MOSFETs don't use the right model.

Which inductance do you see in AC simulation?
 

FvM said:
Looks like the two MOSFETs don't use the right model.

Which inductance do you see in AC simulation?
Click to expand...

In the process parameters model, The values of (cgs0 and cgd0 ....) are there as shown in the previous pics.
I use S-parameters to measure the value of the circuit inductance that is in the side of (Term1).
 

I don't recognize if the bsim3 model is instantiated for the two transistors, apparently it's not.
 

FvM said:
I don't recognize if the bsim3 model is instantiated for the two transistors, apparently it's not.
Click to expand...

I attached pic please see it.
The two transistors have the same name model(bsim3 ).
I have the problem with F0, Q, L, may you tell me how can I get the resonant frequency from ADS and Q, L?
Please guide me to " how can I get the resonant frequency from ADS and Q, L"

 

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