Newbie to ADS transitioning from LTSpice

So I just got started on ADS and previously using LTSpice. I'm just doing some test run just to make sure I know how to use the software and I set it up just right. For now, I'm only concerned with Transient analysis, so need to concern myself with Harmonic Balance or S-parameters analysis and all the other ones.

I seem to be having trouble getting NMOS components to work. If you would take a look at the attached screenshot, I have a simple NMOS Common Drain configuration from an input of common-mode sine-wave VIN. As you can see, the M1 is acting like a constant resistor close to the value of R, making the amplifier just a voltage divider.

Why is this? Do I have the wrong M1 component or maybe I need to fill in more it's parameters?
I got this component from:

Analog_Parts/AP NMOS Devices (No Layout),

whose library is located at:

$HPEEOFS_DIR\oalibs\componentLib\Analog_Parts_vendor_kit,

which was decompressed from:
$HPEEOFS_DIR\oalibs\componentLib\Analog_Parts_vendor_kit.7z


Also, from mentioned library above, why are NMOS and PMOS, Enchancement and Depletion all have the same symbol?

ren_zokuken01 on Feb 16, 2016 3:50 AM

附图/附件

NMOS_test1.png

NMOS_test2.png

I recommend looking at the DC IV curves of the FET to make sure that you have it biased properly. You can select Insert > Template, and look for the FET Curve Tracer one. There are many other devices you could use, instead.

Hi ren,

As suggested by aehoward, you should first use FET curve tracer to access the device IV characteristic. I can see that you haven't biased your transistor properly. In any case, the configuration you are using is common drain - a follower, the maximum small signal gain is supposed to be unity.
See the attached Fig.

Don't bother much about symbols, IEEE defines many symbols for FETs. An IV plot should give you sufficient information, though.

AlexI on Feb 20, 2016 4:31 PM
ignore previous fig., second one is according to your setup.

附图/附件

Comment1.PNG

Comment1.PNG

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