thanx
but i mean in my PDK there is an RF model "spectre model" for the nmos transistor
but when i come to layout, no layout available.
so, i gussed that the model is only a circuit model" a spice model" for the transistor at RF operation
but it is a normal transistor so, at layout i can use the layout of the normal transistor
no , there must be some examples to tell u how to layut the RF transistor ,
at least in the technology document , but sure it will look like ordinary transistor
i say fr , u , if u check , in the process file , u will see how to make a layout of RF transistor
i mean , it will tell how , howmany gate fingers , this model is usful for , and is gate fingers , connetcted from one side or not , with these guide lines , u will draw a ordinary MOS , tansistor
in the ordinary transistor,
there iis a PCELL which generates the layout of it automatically
its parameters are W, L, number of gates
so i will use the ordinary transistor to generate its pcell layout.
but my simulations before layout will be with the RF model
there are 2 ways to connect gate fingers , and this affect the gate resistance
i know that the model of AMS , support single side gate contact , it means the fingers are connected from single side
does the exraction step after layout depends on the spice model or just extracts what is seen with the extractor?
and when i do simulations on that extracted circuit, how does the simulator know that that transistor was an RF transistor?
i think , u wiill specify , it to the simulator , the extactor , will get as transistor , and u will specify the model to be used
also try to get the new PDK , which is HITKIT 3.7 , i think it have new options , and it may make life much easier to u , also try to read process docuument files about process paramters , and spice models
unfortunatly, i can't since i have this PDK with license.
thanx a lot.
and i have another question:
about my VCO i should match its output for maximum power transfer
i measured its output impedence, and i put a matching load Zload = Zout*
but when i did that, no output from VCO and the oscillation is dead.
i will take a look at on AMS documents (now I don't have permission, now I work with other technology)
But there are some design kit which has RF MOS layout instance, but anyway believe in Khouly..he is more experienced in RF field.
I guess now there is also AMS 3.71, maybe it is better
Once I met with an AMS design kit, where I had the models for the high voltage transistors, but I didn't have layout instance for them (and they were in the category called don't use). I was thinking on that.
The model of RF is very improtant. because it will impact you performance especially in high frequency. Usually, we use RF p-cell to get the nmos and pmos.
but you will decide the size and the finger number.