35 Threads found on edaboard.com: Nmos Inverter Layout
What will happen if the pmos is connect to vss and nmos to vdd in an inverter layout?
Analog IC Design and Layout :: 05.03.2008 05:42 :: chapar :: Replies: 5 :: Views: 1180
You can refer to layout example in
Jan Rabaey, "Digital Integrated Circuits 2nd Edition"
Neil Weste, "CMOS VLSI Design A Circuits and Systems Perspective (3rd Edition)"
Neil Weste, "Principles of CMOS VLSI Design"
Baker, "CMOS Circuit Design, layout, and Simulation"
You can use tools like LASI, Microwind, Cadence, or other ED
Analog IC Design and Layout :: 16.04.2006 06:36 :: SkyHigh :: Replies: 5 :: Views: 7303
Our ciruit used a big inveretr as buffer to drive a ~10pF load cap to CMOS level. The working frequency is 155Mbps.The size of the inveretr is for PMOS 12/0.6,m=40 and for nmos,it is 12/0.6mm=20. The process is 0.6um CMOS.
We feel puzzled for how to draw it in layout. There are two main problems.
One is how to place the input and output
Analog IC Design and Layout :: 13.09.2006 23:39 :: chang830 :: Replies: 0 :: Views: 624
I am layout the output buffer whcih drive a ~10pF load cap at 80MHz. The output buffer size is for PMOS 12/0.6,m=40 and for nmos,it is 12/0.6, m=20. The max size of the W in my process is limited to Wmax=20.
Anyone can see any risk for selction the multiple number is high to 40 for PMOS and 20 for nmos?
Thanks in adavnce for (...)
Analog IC Design and Layout :: 18.09.2006 02:33 :: chang830 :: Replies: 1 :: Views: 617
Hallo and help me please...:cry:
i have to make a layout of two stage amplifier and i use technology -TECH_C35B4- but i have some problem because when i go to extract the schematic from my layout i get the same problems:
net_psub net_subtap:Causes multiple stamped connection
net_psub net_subtap:has multiple stamped connection
I have conne
Analog IC Design and Layout :: 28.01.2009 09:35 :: macg84 :: Replies: 24 :: Views: 8301
I am using this book: Basic CMOS Cell Design by Etienne Sicard.
I'm trying to simulate everything for better understanding.
At page 96, Section 4.3 there is an introduction to the "inverter layout".
My question is about this:
p-channel MOS switches half the current of the n-channel MOS.
I understand the reason:
Analog Circuit Design :: 03.12.2010 10:58 :: doupg :: Replies: 9 :: Views: 786
LAT.3N P-well pickup OD to nmos space > 30 um
Connect substrate to GND to do that put M1_SUB in the blank spaces and connect them to GND with metal 1.
LAT.3P N-well pickup OD to PMOS space > 30 um
Connect N-WELL of PMOS to its source to do this put M1_NWELL and connect to its PMOS's source (or VDD).
Put M1_SUB contacts as many as po
Analog IC Design and Layout :: 22.03.2005 21:58 :: eng :: Replies: 6 :: Views: 3146
i'am a beginner in layout i need help in 1.6u tech for layout on cadence vituosou ...i know how 2 use the tool but not the design i need 2 design simple nmos and pmos cells first give me material on different layers etc and on the tech files i need to consider for DRC.....a fast tutorial on layout
Analog IC Design and Layout :: 26.05.2004 09:09 :: chaitu2k :: Replies: 7 :: Views: 1496
I have an question about the ESD.
The picture I've attached is an ESD protection circuit for digital output.
I've used this pad but I wanna change the circled nmos size of output inverter at this time because I need to drive more current than before.
The problem I've encountered is this: increasing W or decreasing L.
Which method i
Analog IC Design and Layout :: 12.01.2006 06:04 :: haemun :: Replies: 5 :: Views: 820
I have a question to lay, because I don't know how full custom EDA tools recognise devices...
when I design a inverter or a nmos layout, how IC cadence system recognise that my
layout is a inverter or a nmos and how IC tool assign device characteristics, parassitic parameters, etc... (...)
ASIC Design Methodologies and Tools (Digital) :: 31.03.2006 14:07 :: OvErFlO :: Replies: 0 :: Views: 539
Is it always that the number of PMOS and nmos transistors in a CMOS gate level netlist must be equal.If not please let me know, why?
ASIC Design Methodologies and Tools (Digital) :: 15.03.2007 02:28 :: pratap_v :: Replies: 6 :: Views: 768
select (PMOS size / nmos size)=Up/Un
Up and Un are mobility of P ans N.
Analog IC Design and Layout :: 20.06.2007 00:36 :: hr_rezaee :: Replies: 6 :: Views: 1184
it is related to layout and i want to know the channel length tracking problem faced while laying out the nmos and p mos say of an inverter
Analog IC Design and Layout :: 12.12.2007 05:23 :: dinesh agarwal :: Replies: 3 :: Views: 684
I'm learning layout. I'm doing my first inverter using a pmos and an nmos transistr from the library. I know that the pmos bulk have to be connected to vdd, the nmos bulk to gnd. That is not clear for me in the picture sowing the layout of the 2 transistors. I drawed the layout of the (...)
Analog Circuit Design :: 09.09.2008 04:10 :: mouzid :: Replies: 7 :: Views: 4057
some inverters take the structure in the picture, why are the gate of PMOS and nmos not straight gate?
and that only obtain longer width? Thanks
Analog IC Design and Layout :: 08.10.2008 08:23 :: shqzhao :: Replies: 2 :: Views: 767
Thanks for the quick reply.Also happy that i made you understand my issue correctly
My substrate connection for both the PMOS and nmos are connected correctly and it can be confirmed by my LVS match result for the individual inverters.I wouldnt have got the correct result if it has some wrong connections
I am having
Analog IC Design and Layout :: 02.06.2009 10:42 :: santom :: Replies: 7 :: Views: 855
i have designed an inverter (5 pmos, 2 nmos), and their gates connect together. but when i run calibre PEX, it says that, there are two gates not connected, floating gate, but i connect them together indeed, and LVS is OK. why? it is very strange, has anyone met this problem before? pls help me. thanks.
Analog Circuit Design :: 12.01.2010 07:46 :: lhlbluesky :: Replies: 4 :: Views: 692
The easiest way is to open Virtuoso from Composer window. Tools-> Design Synthesis -> layout XL. Then from layout XL got to Design -> Gen from source. Lets say you have an inverter in the Schematic window. After you do Gen from source it will place 1 nmos and 1 PMOS and all i/o pins. Press shift f to get the (...)
Analog IC Design and Layout :: 13.05.2010 03:31 :: Vabzter :: Replies: 1 :: Views: 549
If I have a inverter connected directly my pad, then how do I layout this inverter protecting from ESD and Latch Up issues ? please explain in details.
consider for example W/L of PMOS = 200/0.5 amd W/L of nmos = 75/0.5.
Analog IC Design and Layout :: 13.10.2010 02:15 :: krrao :: Replies: 3 :: Views: 1473
you just draw your PMOS and nmos on schematics symbols and then transfer it to layout using stick diagram. =) It is the same.. XD
---------- Post added at 04:13 ---------- Previous post was at 04:08 ----------
Your nmos gate will be conncted to your PMOS gate. Your Source of PMOS to +ve Power supply, Source
Analog IC Design and Layout :: 20.10.2010 00:13 :: john blue :: Replies: 6 :: Views: 606
I think this isolated nmos is a conventional nmos in a P-Well (bulk connected to Vss), but that P-Well is inside an NWell. This N Well should be connected to Vcc. This means that any noise from the P-Substrate (the normal bulk for non isolated nmos devices) cannot get to the isolated P-Well as there is a reverse biased PN Diode.
Analog IC Design and Layout :: 11.12.2010 12:07 :: Colbhaidh :: Replies: 3 :: Views: 1047
I am doing a project on standard cell. Gate is Nand3x4 . The problem is that i need to accommodate layout within PR boundary which 5.44x2.88 (fixed) . I tried layout after splitting (folding )nmos and Pmos gate , but splitting increases my area & it crosses PR boundary. How can i reduce my number of transistor. What are different (...)
Analog IC Design and Layout :: 09.03.2012 08:44 :: jeet_asic :: Replies: 6 :: Views: 532
I`m new, studying electronics and this beginning has been though.
I`ve tried to create a Inverted using gpdk180 technology, but the "NWELLterm NWVIA : No Stamped Connections" keeps popping up every time I make the layout for the PMOS.
I similar problem was occurring with the nmos part. It showed up the "PSUB SUBVIA : No Stamped Con
Analog IC Design and Layout :: 10.09.2012 14:30 :: FAlthoff :: Replies: 2 :: Views: 519
I have circuit in CADENCE, in which I use a cmos inverter with 5 finger for pmos and 4 finger for nmos. I have another PMOS in the same design with 10 fingers. When I do the LVS, it fails because it can not relate the inverter in the layout to the inverter in the schematic. and says the instance is (...)
Analog IC Design and Layout :: 10.10.2012 14:36 :: engrMunna :: Replies: 2 :: Views: 518
I am using Assura RCX to carry out parasitic extraction of an inverter layout. Cadence icfb version I am using is IC5141USR1. The tool is extracting the layout successfully, but the extracted view shows nmos and PMOS symbols in place of metal layers. Parasitics (resistors and capacitors) symbols are present in the (...)
Analog IC Design and Layout :: 16.11.2012 05:23 :: anannya :: Replies: 3 :: Views: 320
Usually people put PMOS on top and nmos on bottom, but in makes no difference. You do your layout how you feel it should be made.
Yes Nwell and Ntub are the same thing.
I did not mean that you should change the transistors. I meant that you should change the substrate contacts.
In Virtuoso, I think the default shortcut for placing contacts is
Analog IC Design and Layout :: 14.08.2013 20:27 :: Yarrow :: Replies: 5 :: Views: 344
it seems a problem for ur circuit. when the source voltage is 0, the nmos is turned on, there is a current flow through the resistor and nmos transistor, the output voltage is dependant on the resistor ratio. so the resistor should be large. It is not easy to work at the high frequency
Analog IC Design and Layout :: 09.05.2006 21:33 :: pfd001 :: Replies: 4 :: Views: 616
I've seen one 1.2um project inverter
Analog Circuit Design :: 10.10.2007 05:04 :: Alan_Nesta :: Replies: 8 :: Views: 1251
a+(b+c)'+c = a+(bbar.cbar)+c
Take + as parallel and . as series, so
4 pmos transistors are arranged as shown below
a b c (a in parallel with c and parallel with b and c which are in series)
( a+(b+c)'+c ) ḃar= abar.(b+c).cbar
therefore 4 nmos transistors are arranged as
b and c in parallel (a
Analog IC Design and Layout :: 14.11.2007 06:20 :: santhosh.mandugula :: Replies: 3 :: Views: 772
I think it should be possible to get an schematic from a circuit description file, do you know the way to do this usin Orcad Capture 9.1?
V1 1 0 PULSE (0 5 1F 1F 1F 5P 10P)
V2 2 0 5
M1 2 1 3 2 M_PMOS
M2 3 1 0 0
ASIC Design Methodologies and Tools (Digital) :: 02.06.2008 15:32 :: vbc :: Replies: 8 :: Views: 7891
I have attached the three diagram of VCO .No.1 is VCO for nmos only tailed bias VCO. No2 is differetial VCO . No3. is Oscillator from cross couple inverter.
Question: why they use 4 terminal nmos as varactor ??what is the advantage of this .?
Question :In No.3 , I know the top PMOS is cross coupled and what is the function (...)
RF, Microwave, Antennas and Optics :: 07.04.2009 01:56 :: gacha :: Replies: 1 :: Views: 944
i got a question in an interview...
after you done the layout for an inverter, DRC says that you need to put a guard ring for pmos and nmos????
option 1: we can stretch p-cell and n-cell...then put a guard ring for both..
option 2: without stretching the both cell, simply put a guard ring then wherever the (...)
Analog IC Design and Layout :: 07.07.2010 03:05 :: padmanabanks :: Replies: 7 :: Views: 1133
this layout maybe could pass DRC but is wierd. the spacing of the vias on the metal seems not minimum spacing and not necessary, should put more contacts on the active areas of the PMOS and nmos to VDD and GROUND, respectively, better use at least two contacts to connect poly gate.
Analog IC Design and Layout :: 26.09.2010 10:08 :: prcken :: Replies: 3 :: Views: 340
I recently downoaded a new PDK which is AMIS 0.5um. I use Cadence 5.1.41, USR6. I am using Calibre to run LVS. My LVS rule file is lvs.ctrl which will invoke calibreEXTc5.rul and lvs.include.
At first, I did a simple inverter with enm(nmos) and epm(pmos). It failed LVS and the errors are that it cannot recognise the nmos (...)
Analog IC Design and Layout :: 16.11.2010 20:11 :: kokykokykoky :: Replies: 0 :: Views: 916
"Multiple Stamped Connections" means that you have multiple nets connecting to the bulk. In your case, I believe, the nmos transistor does not have a bulk connection.
Analog IC Design and Layout :: 22.11.2010 11:53 :: JoannesPaulus :: Replies: 2 :: Views: 685