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15 Threads found on Long Channel Mosfet
With longer channel lengths you avoid the short channel effects (sic!) and achieve better matching (if necessary). If you need to keep the same W/L ratio, the consumed area rises with the square of L . And area costs money.
threshold voltage decreases as channel length decreases. For a long channel device, the depletion layer thickness at the source end of the channel and at the drain end of the channel are much less than the channel length L, and, thus, the depletion charge enclosed by these sections are much (...)
In BSIM3 and BSIM4 models the only discontinuity exists between inversion regions so if OP of your transistor is quite deep in weak inversion You shouldn't see nothing "numerical". Remember that any drain current equations showed in books are only the first approximations based on number of assumptions/simplifications. And if You checked Gray's b
Let's start from "old" technologies (technology node ~0.25 um or older). According to a classical mosfet theory, Vt of a long-channel device is independent of the channel/gate length. If channel length is decreased, depletion regions around source/body and drain/body p-n junctions start to overlap, and the (...)
Much of the low-frequency (1/F) noise generated in mosfet devices is inversely proportional to the gate area. Thus for a desired L/W ratio, a longer longer L means a longer W giving more gate area and lower noise. And generally you want low noise in analog circuits since it affects dynamic range, whereas that noise has (...)
No. long channel is that channel length beyond which there is no effect ov VT or variatin in CD vs Length. This varies by process. It is typicall 10um for 130nm through 350nm and 25um above this. not sure what it is below 130um.
The idea should work. As long as the bottom side FET is turned off well before you turn on the tlc5940. And since you decided on using P-fets for the high side, no need for bootstrapping either so that keeps that pretty simple. Main point of attention would then be to make sure the gate driver for the P-channel mosfet is able to turn it (...)
I am not sure if it is right place to ask some basic question about CMOS Analog Design. if not, please give me some advice on where could I get help about that. My first question is: long-channel mosfet model: The transistor looks like a current source + a resistor. Dose that only happens in Saturation region?
hi all i have read much about designing short channel mosfet ... in small dimensions there are some limitations that help designer to reach best values for parameters ... now i want to design 5 um channel length mosfet but i don't want to use standard biases .... i mean i want to drive most possible current from (...)
I'm just wondering how long must the length of a mosfet be to be considered as a long channel mosfet in a TSMC 0.35 um technology. Please paste any link for me to reference thx
is the SPICE MOS(BSIM3V3) model of 0.35um a long channel or short channel mosfet? It is a model for 0.35um mosfet. Short-channel effects become prominent for channel lengths of 2um and below. Your SPICE model should reflect them as accurately as possible without the need (...)
I have made a few chips with such a long channels, too. The application? mosfet may be used as a tunable distributed RC line... In one element there are at least two: R, the channel resistance and C, the gate oxide capacitance. Just one transistor may work as a simple LP filter.
It depends on the technology model file that you are using. If you are using deep submicron technology the value of gamma is close to 4/3. and for long channel devices as you mentioned it is equal to 2/3.
If you want to use a mosfet as a current mirror then long channel will be better than a short channel device due to channel length modulation effect. also using cascode current mirror is an option to increase output resistance. But you cut from the headroom by using cascodes. As sridhar540 mentioned (...)
Leakage current arrises from recombination process in the depletion regions of junctions. In the case of a diode it is the depletion region around the PN junction. In the case of a BJT it is the BC or BE junction. For a mosfet, it is the Drain-Body Junction for long channel transistors. Short channel transistors could have a (...)