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101 Threads found on Subthreshold Region
Can anyone help me in designing a source degeneration OTA (MOS) in subthreshold region? I know the equation of subthreshold current but from where to get Io value and n value?
Can anyone help be in designing a simple OTA in subthreshold region. The Current equation I know is ID=Io x e(VGS/nVT), what will be the Io? and how can I design the OTA?
Hey all, I'm working on my thesis, an IC circuit for automotive applications. And I found one paper there subthreshold condition are using for transistors. So, I am familiar with the theory about sub-threshold conduction or weak-inversion region, but I don't have any experience... Could you please answer for questions: What are drawb
Can we intentionally design& use mosfet'sin subthreshold region in a circuit(whatever the circuit)? Because in subthreshold region , we can get high gm/id? Is there any drawbacks, ofcourse slow in speed?
Hi i designed an analog multiplier. I found a lot of works on subthreshold and saturation mostly as compared to triode region. In general why not in triode region. What are the general disadvantages regardless of the multiplier circuit design. Becoz if multiplier is required to have a linear operation then triode region (...)
... I think it would be due to the exponential dependence on threshold voltage in the subthreshold region. Can't you provide constant current to the diode connected transistors? Temperature dependency of Vds=Vgs is very low.
I want to try "subthreshold region operation for M5 (simple method)". I have attached the screenshot of my design where i achevied min ICMR of 1V but i need to get it to 0.6V. My design is based on 180nm technology and VDD is 3.3V. Seems you have NMOSFETs with a very low threshold voltage available: V(V3) - Vs
Hi all i am working on subthrshold region using pfet. I have done this before using nfet and using voltage source. I have good idea abt nfet where VGS < VTH and VDS can be neglected no matter wat the value is if its above VTH. But could anyone pls tell me how is it for pfet transistor. In nfet i used two voltage sources VGS and VDS and biased the t
... And I want to use the LL transistors for the digital blocks. I also want to scale the VDD of the digital blocks to operate them in either in cutoff or subthreshold region. Will the power dissipation for the digital blocks be reduced if I follow this method? Sure it will, but their max. operation speed as
Just to put a little more theory to this discussion - in the subthreshold region, source/drain current in a MOSFET is described by the following functional relationship with threshold voltage Vt: Ids ~ exp = exp where e is electron charge, Vg is the gate voltage, Vt is the threshold voltage, k is the Boltz
Hi All, I am designing a two stage miller opamp (pmos input differential pair) in subthreshold region. I am using 32nm technology node. The parameters are given below: 1. Supply voltage = 1V 2. Bias Current = 200nA 3. Transistor Length = 160nm=(5 Lmin) There are no specific requirements but I have to just reduce power dissipation. I am gettin
I'm trying to design an ADC in subthreshold region of operation of the MOSFET. It should consume least amount of power. I searched the web and found ADC types - SAR, Wilkinson, Dual-slope, ∑-Δ, Flash, etc. I also found a paper entitled "An 8-Bit Single-Ended Ultra-Low-Power SAR ADC With a Novel DAC Switching Method and a Counter-Ba
I am currently designing a ring VCO in CMOS subthresold region of operation. The output level of the VCO varies from 0.5 V to 1 V (VDD) with frequency of 50 MHz. Since all the MOS are in subthreshold region, their output resistance is in the range of MegaOhms. So my VCO output resistance is also in MegaOhms. Can you help me design a c
Thank you, SIDDHARTHA HAZRA. Relating to M9, you are right. I can't make it operate in saturation region. It is in subthreshold. I saw that current mirror in this patent and the article says that it is better. I used this structure for that reason. ...
... whether it is in SATURATION or subthreshold region. subthreshold is not a region, but an operation mode. A MOSFET can be operated in subthreshold mode (Vgs < vth) and simultaneously in SATURATION region (Vds > Vds,sat).
If you don't need the last bit of headroom then subthreshold wastes area. One other issue is, how low can you go before leakage currents become too variable (process, temp) to keep mirror fidelity. The higher your upper temperature limit, the less deep into subthreshold you can reliably go while keeping matching or even gross setpoint. Wider
How to represent mosfet in triode and sub threshold region. like self cascode transistor one transistor is in saturation and another once will be in the triode region . i want to calculate output resistance and effective trans-conductance of self cascode MOSFET. can any give the brief note about this topic. thank you
Hi, I am working on the design of some subthreshold circuits based on TSMC 0.18 cmos process. But there is huge difference between the simulation and measured results. I designed a regulator(power consumption=1uW) based on the subthreshold voltage reference proposed in the paper "A 300 nW, 15 ppm/ C, 20 ppm/V CMOS Voltage Reference Circuit Co
subthreshold (or weak inversion) actually isn't a region of a MOSFET's output characteristic like off, linear = triode, saturation or breakdown region - which are identified by a Cadence ADE analysis, (together with No.3=subthreshold) - but much more an operation mode, classified by the deg
maximum load current=50mA I m getting this output voltage but Pmos pass transistor is going to sub threshold region. Vref=1.16v. ... what should be done to operate it on saturation region Hello kishore, subthreshold is not an operating region (meaning a region in the output characteristic
Overdrive voltage VOD = VGS-VTH . Normally you get the VTH from the device model specs. Normally for hand calculation you can assume 200mV of VOD. The purpose of VOD is to calculate the conditions of a circuit that needs to be sufficiently 'ON' rather than being close to subthreshold region. If you have simulation tools you could simulate it as wel
Using OTA for biasing is not good...For BandGAP circuit itselt you are using one more OTA...THis is something not good... About design... Confirm the operating point of all MOSFETs as all should be in subthreshold region... Best method to design low power subthreshold circiut is gm/Id method...Comparatively you will get w/L ratios faster (...)
No this is not a good idea at all. I am assuming that you are interested in the generating some kind of clock. The current starved inverter(digital gate) ring oscillator are used mainly to change the frequency using a Vref signal which can be adjusted. So depending upon the temp,vdd and process your design can be made to generate a certain frequenc
hello I want to design a current source in nano amp range from a reference current source. But the mos is entering in the subthreshold region in order to flow nA range current. I am using GPDK-180 nm technology model file. Is there any option to avoid the subthreshold condition for the mosfets? can you tell me what is the min
Hello all Kindly, I eould like to ask how the transister working int the subthreshold region (weak inversion) has a high transconductance (gm) and hence high gain but small GBW. if we have high gm then we must have GBW as (GBW = gm/Cc). thank you
Are “gm” and “rO" values or equations in subthreshold region as saturation region??????? Hi Ania A comment on ro . when your current has changes , ro will be changed . so if your required out put resistance is high , it is important to pay more attention to the ro . By the way , what do you mean by (...)
I think your question isn't quite clear, may be you mix up subthreshold and saturation resp. linear region? subthreshold (or moderate resp. weak inversion) is an operation mode, meaning in which range of Veff = VGS - Vth the FET is operated, whereas the linear or saturation region designate in which part of the ID vs. VDS (...)
Please read the below paper. You can find a lot of thing through the text. S. K. Gupta, et al., "Digital Computation in subthreshold region for Ultralow-Power Operation: A Device–Circuit–Architecture Codesign Perspective," Proceedings of the IEEE, vol. 98, 2010. Could you access IEEExplore? Feel free to ask more ...
...i need m7, m9 to act as resistance of average value 1Mohm. (in sat i think we can't get this value from a single transistor)... Then you must operate the transistors in triode region!But i doubt if you can get such a big value of ron when the switch is closed... i just bothered of how to connect the gates(M7,M9) to ensure
weak inversion region and subthreshold region are the same regions. If you look at the cross section of the layout of a simple mosfet(nmos and pmos) you can see a virtual BJT b/w NMOS and PMOS thru which a current flows: leakage current. When your MOS is off(Vg
Hi, in subthreshold region the drain current is given by equation 5.41. My question is that for a differential pair in subtrheshold region, how can we get equation 8.14 from 5.41. Please see the attached figure for
1.)Perform dc analysis 2.)From the top menu of ADE L window find the choise Print DC Operating Point 3.)Hit on the transistor of interest 4.)Read the report that comes up and finally 5.)Check the validity of the above inequalities to verify the region of operation This was useful. I got to see the operated re
Hi I'm confused with NMOS and PMOS transistors in subthreshold region. Which of them has the higher current value, for a given value of Vgs? Which of them has the higher subthreshold slope? Which of them has the higher value of threshold voltage? I'm working with 90nm Tech. Rosa
i am trying to design an op amp with subthreshold operation. May i know which MOS are allowed operates in subthreshold region? the input pair? the active load? what about folded cascode configuration? As far as i know, the current mirror must be in saturation to ensure accurate copying. MOS op
It depends on what region transistors work. The circuit can be designed for satuation region or subthreshold region. When they work under subthreshold region, the voltage drop will be close to the formula. On the other hand, satuation region will have different story.
Hello, The first thing you should do is to make sure all of your transistors work in the saturation region (i.e. not in linear region or subthreshold or cutoff region).
Hi I used the following equation in order to model the MOS current in subthreshold region: ids=I0* exp((Vgs-VT)/(n*Vth))*(1-exp(-Vds/Vth)) ? With Vgs=100mV, I ploted the current versus Vds. But the result is diffferent from the
Try a MOS transistor biased in subthreshold region.
Hello, I am trying to implement a subthreshold level shifter, going from 0.3V to 1.2. Most of the designs that I have found online do not function in the subthreshold region. One of the functional level shifters that I found that DID work as desired is pictured
While you can get very large resistances with subthreshold FETs, any noise will give you large temporal variations in the effective resistance. It is by no means a reliable resistance.
Hi How can I design an oscillator in subthreshold region? Is it possible to have a ring oscillator with fc=200mhz ? Tx
Hi Does anyone know about Comparator design challenges in subthreshold region? Tx
Hi How can I design a pulse generator in subthreshold region with Vdd=300mV and pulse width of 2nSec? :|
I was studying about the subthreshold region operation of a CMOS inverter If I have a device of threshold voltage of NMOS =0.2volts , and I want to make a CMOS inverter with it that can operate in sub-threshold region. plz suggest the vdd for the circuit I should use I already used a Vdd of .150volts but could not get correct (...)
I was trying to simulate subthreshold region operation of a CMOS inverter If I have a device of threshold voltage of NMOS =0.2volts , and I want to make a CMOS inverter with it that can operate in sub-threshold region. plz suggest the vdd for the circuit I should use I already used a Vdd of .150volts but could not get correct (...)
I am trying to simulate the operation of cmos inverter in subthreshold region. threshold voltage of my device is aroung 150mv . Please suggest the parameters I should use to simulate like vdd and output capacitance I should use.. the subthreshold current of my device is of order of nA I will be thankful for any help
Using a MOS as resistor in triode but in subthreshold region is difficult because the change in DC voltages change also the effective resistance in an exponential way. The circuit solution is that the gate drive is dependend on the resistor terminal voltage. But the substrate effect make the implementation for NMOS difficult. It is easier with isol
Hi, everyone I am a little confused about the concepts and the characteristics of the different MOSFET operation regions. for MOSFET operating under saturation region it is called triad region under certain condition, the MOSFET can be used as a resistor, so it is also called linear region The linear (...)
Hello All, I have some questions about cmos comparator design. I need to design a very low power comparator. The Vdd = 3.3V, Midband Gain ~55dB, GBW ~500KHz. The current needs to be as small as possible. I plan to put the differential pair in subthreshold region and the rest of the transistors in strong inversion or moderate inversion.
There are many different models. Just make a google search on "subthreshold transistor model"