47 Threads found on edaboard.com: Mosfet Transconductance
What are you doing?
You can use your mosfet switch to limit the inrush current. Look up mosfet transconductance, for a given Vgs a mosfet will allow a certain Ids.
The reason there is an inrush is because when you first flip the switch to your SMPS the bulk input capacitor is discharged the inrush current is the (...)
Analog Circuit Design :: 20.11.2008 15:35 :: max0412 :: Replies: 5 :: Views: 4029
I want to know which are the capacitances that wll be effected by scaling of a transister.What are the new capacitances that will come into picture.
Analog Circuit Design :: 24.05.2005 15:54 :: venkata :: Replies: 7 :: Views: 1453
mosfet is voltage drive device, what's the point of measuring Ft? And what is the usage of Ft for mosfet?
RF, Microwave, Antennas and Optics :: 29.05.2005 23:58 :: _RFIC_ :: Replies: 1 :: Views: 913
The main different is that the JFET have a PN juntion for it have high input impedance.
The mosfet have isolated gate with polysilicon.
Electronic Elementary Questions :: 30.06.2005 11:44 :: JoseLeonardo :: Replies: 10 :: Views: 45238
I have a few questions about fMAX and fT of a mosfet:
1. What's the definitation of fMAX, the maximum oscillation frequency of a mosfet?
2. I remember the definition of cut-off frequency fT is the frequency when current gain Iout/Iin = 1. This gives out fT = gm/Cg. My question is: is transconductance gm a function of frequency? (...)
Analog Circuit Design :: 25.04.2006 20:46 :: jlee :: Replies: 2 :: Views: 11246
Mr.venkat3271 for ur kind information the drain current Id of a mosfet depends on the effective voltage.... please do refer some material on mosfet.....
Electronic Elementary Questions :: 21.06.2007 13:47 :: A.Anand Srinivasan :: Replies: 3 :: Views: 914
mosfet Pdf file. You gothrough this file fully you can get an idea about your question
Analog Circuit Design :: 24.08.2007 01:29 :: money_kandan2004 :: Replies: 5 :: Views: 565
Why mosfet IS OPERATED in Saturation region in most of the analog applications? please explain with some references..
Analog Circuit Design :: 11.02.2008 04:14 :: sandeep_sggs :: Replies: 1 :: Views: 1764
Please tell me
1.how to select ucox for a mosfet?
Is it using tox?But is er and eo constant?wnt up and un gm(transconductance )for a particular technology viz., 0.35um ,fixed for a mosfet?if so, how do u find the value?
3.how to find output parasitic capacitance values for a cmos circuit
Analog Circuit Design :: 25.08.2008 09:48 :: sandhaajith :: Replies: 3 :: Views: 1261
I'm new to mosfets and mosfet-drivers and would just like to check if I correctly determined the correct mosfet + driver to use using the correct calculations.
Any criticism/suggestions are welcome. Thx in advance!
mosfet H-bridge Driver: MC33883
Analog Circuit Design :: 18.04.2009 13:58 :: Rewn :: Replies: 0 :: Views: 956
I'm using a CMOS process, in which there are two types of NMOS devices with the same gate oxide thickness. But their gate-source break down voltages are different. Why it is like that? Thanks for any information.
Analog IC Design and Layout :: 07.07.2009 20:11 :: tia_design :: Replies: 7 :: Views: 1545
I am new to this filed on analog design. I am reading the book by Behzad Razavi on "Design of Analog CMOS Integradted Circuits"
While reading on mosfets, I encountered an equation for transconductance which says that : gm = 2 * Id / Vgs - Vth .Its explanation states that Transcondutance decreses with overdrive (Vgs - Vth) when Id is co
Analog Circuit Design :: 12.07.2009 14:26 :: Amninder :: Replies: 18 :: Views: 16269
.i modify gate voltage to mos transistors,therewith the high mos resistance is controlled ,and the fc is further on controlled.:D
In weak inversion the mosfet transconductance is given by "Id/nKT" i.e. independant of Vgs. So assuming you are using MOS as R or simillar to OTA-C implementation, the Res = 1/gm. So
Analog Circuit Design :: 01.10.2009 07:53 :: zopeon :: Replies: 3 :: Views: 632
Do you know the relationship between transconductance (u*Cox) parameter and technology?
In other words how does change that parameter for a mosfet in .25 micron to 0.18micron?
Analog IC Design and Layout :: 01.04.2010 10:33 :: ahmadagha23 :: Replies: 11 :: Views: 1964
which transistor provide more gain...Enhancement mosfet or Depletion mosfet? Please explain with solid reasons.... :) :)
Electronic Elementary Questions :: 28.06.2011 15:54 :: raditsme :: Replies: 1 :: Views: 702
below image show the Simple CS transistor model with the transconductance nonlinearity and output conductance
below equation is KCL at drain , I cant understand 4th part of this equation, please explain me how it dr
Analog IC Design and Layout :: 01.02.2012 03:14 :: perado :: Replies: 0 :: Views: 267
I need to plot transconductance(gm) of a mosfet(NMOS) in LTSPICE. Any idea how to do it? I am using TSMC 0.18um technology file.
Also I need to observe gm upto 5 figures of precision. Please help me with that too...
Right now I can view gm using dc operating point (.op) and going to Menu Bar->View->Spice Error Log (screenshot attached)
Electronic Elementary Questions :: 01.04.2012 07:56 :: nyk :: Replies: 0 :: Views: 1063
How would you like to define a mosfet's small signal input current?
Igs = Vgs * 2πf*Cgs ? Not too meaningful, I fear!
Analog IC Design and Layout :: 23.08.2012 15:20 :: erikl :: Replies: 8 :: Views: 1161
OTA -> Operational transconductance Amplifier.
An OPAMP is Voltage Controlled Voltage Source thus u can not connect output of them together but the output of VCCS (Voltage Controled Current Source) can be connected together, cos if the input voltage of any of them is zero, then the output is open circuit.
u can use a simple jfet, mosfet or even a
Analog Circuit Design :: 12.08.2004 00:05 :: goodboy_pl :: Replies: 9 :: Views: 1238
beta is the transconductance coefficient.
in simulations, beta is one of the parameter used in mosfet SPICE modeling.
Analog Circuit Design :: 09.04.2005 02:01 :: arbalez :: Replies: 9 :: Views: 7350
It is the gate length of the FET.
effective length of the distance in the near-surface region of Si substrate between edges of the drain and source regions in the field effect transistor (including mosfet and CMOS).
Reducing gate length is an effective way of reducing the transconductance of the channel. This implies that switchin
PLD, SPLD, GAL, CPLD, FPGA Design :: 13.07.2005 10:09 :: checkmate :: Replies: 3 :: Views: 1971
I agree with the above post. The major difference in the bipolar and the mos models is that between the Gate and other terminals, there is an open connection, while in a bipolar, there is a base resistance rb which will connect it to the collector terminal. Capacitances like Cπ and C? are replaced by CGS and CGD. So, the small signal modelling
Analog Circuit Design :: 25.07.2005 02:15 :: Vamsi Mocherla :: Replies: 4 :: Views: 626
it's the equivalent of using a delta-vbe (ptat current) for biasing an op amp. basically your bias changes with temp inversely proportional to the diff pair, so you can keep the transconductance (and therfore GBW) constant over temp. now your room temp compensation *should* work over all temps. it's a good idea for any diff pair actually since i
Analog Circuit Design :: 10.10.2005 17:57 :: electronrancher :: Replies: 5 :: Views: 1126
You can simulate a single transistor in Hspice and get almost every model parameters. command .OP and DC sweep will do this job. For example, wanna get Ueff(effective mobility) of M1, just use: .probe dc ubeff(M1). Also gmo(m1) means transconductance of m1, vdsat(m1) is ..., I think you should know this : )
Sometimes maybe you don't know how to n
RF, Microwave, Antennas and Optics :: 10.11.2005 23:33 :: flamingo :: Replies: 5 :: Views: 1491
as far as i thought ,,body effects makes the threshold voltage of mosfet changes,,,so,,you must care when placing the mosfets in series that they still operate in saturation region and this depend to a great extend on the supply voltage ;as it shrinks down ,placing mosfets in series becomes more difficult
check this also
Electronic Elementary Questions :: 28.04.2006 04:09 :: husseinadel :: Replies: 3 :: Views: 1807
With your questions, I noticed a discrepancy in my original post: The transconductance of Q2 should be 370uMhos.
The transconductances that I presented were not really calculated from any real transistor sizes or process, just a guess for a starting point.
The noise current in a mosfet is sqrt((8/3)*K*T*Gm), in amps/sqrt(frequency). (...)
Analog IC Design and Layout :: 29.06.2006 10:26 :: JPR :: Replies: 12 :: Views: 1274
To measure it experimentally you can obtain the waveforms of the voltage and current on the output and then divide them with an digital oscilloscope, and with a single mosfet you can assume that the output resistance is the drain resistancei you look it from the drain and the inverse of the transconductance if you look it from the source.
Electronic Elementary Questions :: 15.08.2006 16:50 :: Andrew8611 :: Replies: 4 :: Views: 4973
The reason you need the level shift in the bipolar design is to keep Q5 & Q6 out of saturation. Without the level shift the potential on the base of Q5 & Q6 will be too high which will lead to forward biasing the collector-base junction (saturation) of these transistors. This will kill your beta, Ft, thus the ac performance of these transistors.
Analog IC Design and Layout :: 04.12.2006 01:51 :: krashkealoha :: Replies: 3 :: Views: 1685
unsymmetric input diff pairs cause mismatch to your diff stage. if you notice you have a "tail" to control the current flowing through both pairs, ideally you have identical sizes so same currents flow through them. since current is proportional to W/L in a mosfet, diff W/L ratios mean different current through your transistors. usually gain
Analog Circuit Design :: 08.04.2007 15:46 :: acbalbason :: Replies: 2 :: Views: 547
In CMOS Process, ONO layer is known as reoxidized nitrided oxide.
This layer was repleaced with SiO2, especially gate oxide of mosfet.
it is said that Deep submicron mosfet with ONO gate dielectrics was superior to the mosfet with SiO2. The reasons are,
1. have improved saturation transconductance ( Frankly, I (...)
Analog IC Design and Layout :: 29.05.2007 06:15 :: 020170 :: Replies: 4 :: Views: 1566
The simple way is to have resistor series connected to the inductor, or power mosfet. Then you can detect the voltage drop on this resistor and convert this voltage drop into current with V-I converter.
Analog IC Design and Layout :: 21.12.2010 01:36 :: leo_o2 :: Replies: 4 :: Views: 1966
i need to simulate "second-order Gm-C bandpass filter" with 10.7MHZ center frequency that its schematic is below.its structure is nauta transconductance.the reference journal is attached.
i need help for simulate this filter by HSPICE software and 0.35um cmos standard parameters.
it is not any problem to design this filter with c
Analog IC Design and Layout :: 14.02.2008 15:31 :: aminmahdi :: Replies: 0 :: Views: 481
i need to simulate "second-order Gm-C bandpass filter" with 10.7MHZ center frequency that its schematic is below.its structure is nauta transconductance.the reference journal is HERE:
i need help for simulate this filter by HSPICE software and 0.35um cmos standard parameters.
Analog Circuit Design :: 14.02.2008 15:33 :: aminmahdi :: Replies: 3 :: Views: 848
Hi!Why 'gate width' is important in amplifier or mosfet? large gate width or small gate width which is good and why?
RF, Microwave, Antennas and Optics :: 07.03.2008 09:15 :: CQCQ :: Replies: 3 :: Views: 844
I am confused how can i plot the operation point parameters with sweep variable in Spectre?
For example, how to plot transconductance of a mosfet versus Vgs?
Thank you so much
As i know, use the belowing:
set vgs as a variable, sweep vgs, set plot as OP("/M0","gm")
Analog Circuit Design :: 15.04.2009 09:16 :: iamxo :: Replies: 8 :: Views: 3282
How to calculate IGBT "ON Resistance". I am using SGP23N60UFD in my design. In mosfet parameter(Rdson) is there for "ON Resistance". In SGP23N60UFD data sheet no where such parameter is not mentioned.
V. Naresh Kumar
Analog Circuit Design :: 26.06.2009 07:01 :: nareshgtr :: Replies: 4 :: Views: 2005
Set "DevOpPtLevel" as "Brief" or "Detailed" in DC Analysis Setting parameters.
See the followings.
DC operating point data is generated for this model. If a DC simulation is performed,
RF, Microwave, Antennas and Optics :: 20.12.2009 04:57 :: pancho_hideboo :: Replies: 2 :: Views: 1420
please tell me how to calculate the biasing voltages of conventional folded cascode amplifier.. i am attaching my circuits.. also tell me how to calculate the device sizes of mosfets... please reply.....
Analog Circuit Design :: 04.05.2010 23:33 :: sai143 :: Replies: 2 :: Views: 1024
P1dB is measured at output and not at input? P1dB - at output measured - should be proportional to P-DC. If this is not the case your mosfet goes into voltage saturation or current saturation and not both simultaneously. This is due to output mismatch.
Analog IC Design and Layout :: 17.10.2010 10:37 :: bluetooth :: Replies: 11 :: Views: 3017
I see many posts on design of two stage opam.But honestly,I don't know where to begin and everything is seeming vague.I wrote the equations(transfer function)of a two stage opam from the equivalent circuit.Now i don't understand a few basic things
>>Is the equivalent circuit representing two opams a combination of a few mosfets or two single
Analog Circuit Design :: 28.12.2010 02:21 :: cranky_here :: Replies: 4 :: Views: 639
Yes, you are right, the voltage variation is lower in the shown current range. I came to the same conclusion when checking the results. This is because you have selected a mosfet with a large Idss and respective transconductance. For a real voltage regulator, you would also want a tightly tolerated output voltage, which gonna be more problematic.
Analog Circuit Design :: 26.02.2011 09:47 :: FvM :: Replies: 10 :: Views: 791
With metal gate you have a single work function and
have to tune the body to get VT. With poly gates the
doping could be (but was not necessarily) another
degree of freedom; I saw in-situ-doped and S/D-doped
But the real benefit of poly gates was the self-aligned
mosfet where poly defines the channel sharply. All of
Analog IC Design and Layout :: 06.04.2011 11:12 :: dick_freebird :: Replies: 2 :: Views: 480
Well u can refer the tutorial on plotting the gm of the circuit in cadence.
Hope this helps u.
Analog IC Design and Layout :: 20.03.2012 05:13 :: muffassir :: Replies: 3 :: Views: 898
YES, you can use a scope as a curve tracer to measure the current gain in a transistor or the voltage gain in a FET or the transconductance of a mosfet.
Simply use series resistor on emitter to monitor current and display as Channel 1 and Voltage as Channel 2 and use scope in XY mode to see the input versus output.
Remember transistors are curr
Electronic Elementary Questions :: 09.06.2012 09:27 :: SunnySkyguy :: Replies: 10 :: Views: 551
if you regulate the VDS > Vg-Vth then you are adding drain resistance (xΩ load vs 0Ω shunt)
If saturated then then you get the green line.
Electronic Elementary Questions :: 13.06.2012 05:12 :: SunnySkyguy :: Replies: 15 :: Views: 1876
1. Ideally, mosfet have 0 resistance when on i.e. saturation and infinite resistance when off. In practice, it has nigligible on resistance and very high off resistance. Using ohm's law is one way to find out the resistance. but generally linear region resistance is also very small. Look into the datasheet to find all these parameters.
2. mosfet i
Electronic Elementary Questions :: 08.03.2013 04:38 :: ashugtiwari :: Replies: 6 :: Views: 322
I want to calculate the transconductance gm of a mosfet in ADS (Advanced Design System). I used equation gm = diff(I_drain,VGS) but it didn't work.
ADS displayed the error: While evaluating "gm": left operand: ee_boolparameter value required
Can anyone help me?
Analog Circuit Design :: 18.04.2013 04:53 :: hien.rfic :: Replies: 0 :: Views: 340