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Matching Transistor Length

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9 Threads found on edaboard.com: Matching Transistor Length
Hi I m designing a two stage ota using gm/id method. I have a problem in picking the length of the transistor. I have chosen a large length for large gain and good matching. And my ft is around 10 times the UGB of the ota. Are there any relationship between ft of the transistor and UGB of the amplifier. I (...)
for NMOS pair, bottom mirror should have larger L to obtain good matching. the top pair are used to enlarge the output impedance
Another reason is that the output impedance of transistors are very much smaller if minimal length are used, resulting in low gains. Short channel effects will also increase the complexity of the design. But still, matching forms the most important consideration. It's one thing to design a circuit to write a paper, where you only need one (...)
Hi, I have an operational amp implemented by using asymmetric transistors. I guess it's not a good idea to share drain and source in a pair of transistor concerning match. Do you guys have any idea about layout matching of asymmetric transistors?
in circuit design,how to choose L of transistor for analog module(such as opamp)? according to modulation, matching, or noise?but how? what's the relationship of them? pls give me some clear advice or explanation.
In analog design, matching is more important than gm. Therefore, make the MOS length and width at least 2~3 time from the minimum.
Folding would be reducing the width or length of one device using a multiple factor ie w=10 l=10 number of transistors 1 can also be w= 5 l =10 number of transistor 2 perhaps to reduce space or to improve matching. and fingering ( interdigitating) is done using multiple transisors to achieve matching.
May be because of matching or exact ratio with another transistor that use the same W/L (somewhere else in schematic).
the size of the transistor will affect the speed and matching, because the existance of non-zero on-resistance and parasitic capacitance. if the minumum size is ok for you , surely ,you can design it because it will save area. Howerver,if the minimum size of the transistors is not fine for your design. you need to tune it. the above (...)