※ 引述《kobetwo (高跟美腿控)》之铭言： : ※ 引述《pow (体脂肪35%)》之铭言： : : http://www.mosis.com/Technical/Testdata/tsmc-035-prm.html : : Look for the column: K' (Uo*Cox/2) : : Also, : : In the SPICE models: : : U0: Channel mobility (unit:m) : : TOX: gate oxide thickness (unit:cm^2/V/s) : : You can calculate COX=Permittivity_of_OX / TOX : : *be careful of the units conversion : 我之前设计OP也有这个问题,我发现W/L比会影响到MOS的模型 : 这些模型例如有pch.1 ~...~ pch.11 : nch.1 ~...~ nch.11 : 而每个模型的U0都不尽相同 : 如果想要把U0给定,就是先决定用某个模型,那麽W/L比值需要定在此模型容许范围里 : PS.难怪做类比电路需要很多经验,电子学观念通还是不够的 囧 actually...those are just parameters for modeling you should be able to come up with some method to set up a test circuit to get the W/L you need. Example: You want to make a tail current source for a diff-pair. 1. Put down the NMOS with Width= variable Wn1 Set the Length=3*minimumL to get around channel length modulation 2. set the minimum VDS 3. set the range of VGS 4. Sweep Wn1 and VGS to get IDS you want This way you don't need to do hand calculation 'cause when you draw the test circuit and figure out what data you need to measure, you are writing down an equation (or set of equations) and let the software help you "solve" the equation(s). But you must have a very good understanding of how the circuit works. Or you'll be employing "shot-gun method" for larger circuit, such as an Op Amp. Setting everything an variable and hope you can find an optimized performance is not going to work. You would rather spend lots of time understanding how circuits work and setup the test circuit than randomly walking in the sea of circuit topologis adn variables. --

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