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34 Threads found on Mos Width Length
how to find or assign of width and length ratios for mos transistors in 45nm especially in cadence tools suite(virtuoso)
Hi In most situations, we need to paly by using w/l of the mos since it changes most of the parameter we as erikl said, for designers, width and length is the main factor deciding the performance. All performance measures can be determined by width and length. Thanks
Hi all, I've got a question about the mos transistor length range in HCmos 9GP 130 nm technology. I've implemented a current mirror circuit for SAR ADC with high speed transistors. The problem I have at the moment is I cannot increase the high speed transistor length beyond 0.4u in cadence simulation. Here simulation in (...)
Please anybody help me to know ,Is it neccessary to maintain the same distance between actual device and dummy device in analog layout? Consider less area available.
Where to define the V-I characteristics of a new created device\part. e.g., I have to use mos and I created my own part using ?NEW PART? in ?USER DEFINED PROPERTIES? i added new property width, length but where I have to give the characteristic equation which defines the relation of voltage, current, W/L ratio and other parameters.
Can any one tell, whether the line width and the channel length are same! what is meant by line width of a mosfet? and please provide me some examples!
Hi all, My questions are as //.///I am newbie in cadence. 1)I want to draw the FETs manually In mircowind software by clicking on mos icon we can fill it there the length and width to draw the mos in the layout. Can we draw the layout similarly in Cadence Layout editor without the need to exec generate from all (...)
Because of the (W/L) which is the width over the length factor. You are changing P mos width rite? But the Kr changes. It will change the voltage transfer characteristic of the inverter. From there only,you can see the fall time and rise time.
is there any problem if we do not keep the drain and source areas same width and length like emitter and collector in bipolar junction transistor???????? thanks..
Hi, For simple rectangular mos transistors, it's easy to identify width and length depending on direction of current flow. If you've complex irregular mos transistor (not like a spider :D but mostly like a rectangle having many glitches from one or both sides), is there a scientific method in this case (...)
Hi kickbeer, I hope this link will help you a bit.
Hi, If u r using GPDK or PDK, then model names are automatically bind to your mos symbol and you can see this model name in context menu (edit-> prop-> objects) If you are using a general models, then you should manually add these to mos symbols while placing it(generally) along with width and length. so that they will (...)
We often use this type mos as large resistor. I wonder if there are some rules in thumb for using this "inverse W/L ratio" transistor.
You can make a mosfet with either big L and small W, or small L and big W. Both are fine, I 100% guarantee it and use them all the time. If you are really talking about W (perpindicular to direction of current flow) then for very large W (greater than 5-10um) you should break it up into multiple fingers. For my 100,000um power switch I use 1
the width and length of the mos capacitor in the layout should match the schematic. other property matching such as device type should also be observed.
In analog design, matching is more important than gm. Therefore, make the mos length and width at least 2~3 time from the minimum.
Look into a design manual. They usually extract models for specific W and L of mos device. Those are the "exact" values. Then they include scaling which is theoretical approximation. I use max W as 10um and if I need bigger size I use parallel multiple. Then you can use virutaly any W you want. L is the litography limit for the technology. For d
Hi,all How does dracual LVS extract channel width and length of mos in layout? I mean how the "W=** L=**" expression is obtained by dracula lvs run. This expression is locating on the right side(layout devices, nodes and parameters) of .lvs file? and, if i want to change the formula for calculating the value of W or L, even those of (...)
How does dracual LVS extract channel width and length of mos in layout? and, if i want to change the formula for calculating the value of W or L, what should i do? It is always easy for calibre lvs users to find the expression and revise. Thanks in advance
Hi __| __|| | ||__ __| | | __| |__|| ||__ | this will act as a W/2L mos transistor (in sat region). regards
Hi all, I have read a paper mos Operational Amplifier Design? A Tutorial Overview by P. R. Gray recently, but there is something I can't understand very clearly. So I think I need your help. Here it is: For constant drain current decreasing either the channel length or width results in a decrease in the gain, the latter because of the fact (...)
Hi! For calculation of Area of a mos device ,W and L are the required parameters. A model file defines all parameters of mos except these two. So having model file only will not help u for area calculation. U hav to specify W andd L values in ur SPICE file while including the model . Kundan Kundan, Check any model
it means that channel lenght is short :D, u know the mos is isolated gate device, where the gate potential "metal, infact polysilicon" is used to control the flow of the current in the mos , the metal gate dimension are length "L" and width "W" , the current is proportional to the aspect ration W/L"this means that aboslute (...)
how to add the mos As,Ad,Ps,Pd (area of source & diff, perimeter of ....) in cadence? i.e. what are their equations? and can i enter them as equations? or i have to change them every time i change a mos dimensions.
Hi, For the Transmission gates we use the minumum width of Nmos and Pmos. I have no idea for the flip-flops.
Usually mos transistors in triode region are used for switches. Depending on the configuration, either an Nmos or a Pmos or a combination of both is used. The length of the mos is kept minimum to reduce parasitic capacitances. Depending on the application, the width is adjusted. (...)
1. after netlisting, if the NRD does not exist, does that mean NRD=0 2. how to calculate NRD length of drain/width of drain or 0.5 length of drain/width of drain(since the contact is in the middle) Thanks
We ofen mixed 2 mos (Current Mirror ) by finger. We get the same Rs of mos , and can improve matching .
Channel length is very short regarding to width. It's possible to be channel length modulation effect. Or Vt can be related on W/L ratio. For mos transistors, the theoritical values can vary with other physical parameters.
I am using model of CSMC.The gate-width of nmos and pmos are not found in the netlist, but gate-length exist. I see the CDF of nmos and pmos, the parameters of gate-width are the same as gate-length.I can't find the reason. Thanks!
Do you mean the parameters given in a SPICE file? If yes then which level. The higher level models do not have λ as a parameter. Its always better to derive these parameters by plotting the DC curves of a mos device of known length and width for your hand calculations.
Maybe the large size transistor is indispensabe. On base of some research , the minimum( the line wide) width transistor is used in the analog design for the advanced foundry that is a trend. As the width reduced, the second effecs of transistor(mos) is appear. which one of them is dominant is varying as the foundry changes and the (...)
1. measure the open loop gain. the most important parameter is the input offset voltage. check on these a rule of thumb, the length of the mos is 2-5 times bigger than the min length. for the width, consider the matching and the current mirror.
Hi, 1. Which skill function can change a mos' length and width in the schematic? 2. Whcich skill function can be used to flatten all layout database ? 3. Which skill function has sizing function for layout database? 4. Is there a tool can follow the design rule to automatic sizing layout database? Thanks.