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Questions tagged [transconductance]

The transconductance of a device relates the current through the output of the device to the voltage across the input of the device.

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Dot parameters LTspice - Transconductance of MOSFET

Below is a very simple circuit to extract the transconductance value of the MOSFET. As it is known, transconductance is known as Delta (Id) / Delta (Vgate). For the gate voltage, I defined it as .step ...
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Analyzing \$g_m\$ vs \$V_{in}\$ for a common source config

I had this doubt while going through the book "Design of Analog CMOS Integrated Circuits" by B. Razavi, if we are to plot \$g_m\$ vs \$V_{in}\$ for the above circuit, then we have \$g_m\$ =0 ...
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Short Circuit Transconductance Cadence

Hello, I am curious about hand calculation about overall Gm by using short circuit transconductance. I got M2 of gm is 1.176mA/V, M2 of gmb is 0.2078mA/V. It should be around 1.14mA/V by using short ...
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MOS transconductance plot using LTspice

I am trying to plot the transconductance of a MOS using LTspice in DC sweep. However, I heard that there is no dy/dx function in LTspice. Therefore, I came up with another way. Keep the drain voltage ...
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MOSFET transconductance

I am curious what the relationship is between the drain bias current and the transconductance of a MOSFET? For instance, say you set V_DS but you double the drain bias current, how would this affect ...
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Fully Differential OTA

Based on the figure below, could you explain how a differential ota works ? how can I get the transfert function if I want to set a pole or a zero at the output with a differential resistor and a ...
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What would happen to the drain current of a D-MOSFET at cutoff voltage when we are going to plot the tranconductance curve?

Here, $$I_{DSS} = 8 \,\textrm{mA}$$ $$V_P = -6 \,\textrm{V} $$ Equation for the drain current, $$ I_D = I_{DSS} \left(1 - \frac{V_{GS}}{V_P}\right)^2 $$ So, the cut-off voltage is where the Drain ...
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Finding transconductace Gm=Isc/Vin for a common source MOS amplfier with source degeneration

I am looking to find short circuit current over input voltage to find transconductance Gm for a common source amplifier with source degeneration. To do this, I first shorted the output terminal and ...
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Cannot Find MOSFET Transconductance - Incredibly Confused

I am tasked to find the gain of this small signal circuit drawn in my work. I have absolutely, NO idea how the professor came up with his answer. I would e-mail him, but he doesn't respond on weekends....
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Transconductance photodiode?

I'm having trouble finding a theoretical explanation about the transconductance photodiode behavior, the materials I find on the internet they talk about the connections, but not the behavior, in case ...
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What is dynamic range in MOS transistor?

In Analog CMOS integrated circuit book, page 696, edition 2, it is stated that: In order to restore the dynamic range, the transconductance of the transistors must be increased by a factor of square ...
mohammad rezza's user avatar
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Converting 1 - 5V signal to 4 - 20mA signal

reference: https://www.analog.com/media/en/technical-documentation/technical-articles/D61_EN-Convert.pdf I am trying to convert a 1-5V signal to a 4-20mA signal using this circuit but it was not ...
Karl's user avatar
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Interview Question

This Circuit was given. While I possess knowledge of each component within this circuit, including an understanding of feedback and gain margin, as well as familiarity with transconductance ...
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How to derive effective transconductance versus oscillation amplitude in a oscillator?

In the page below in the lecture note shows a plot of effective transconductance versus oscillation amplitude. How is it derived? Or is there any source to derive effective transconductance versus ...
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Bidirectional voltage-to-current converter

How to make the following voltage-to-current converter bidirectional, so that bidirectional current can be driven through the load?
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Push-Pull voltage-to-current converter

How to make the following voltage-to-current converter bidirectional, so that it maintains the requested current through the load, even when that load stores energy and attempts to oppose the ...
George Robinson's user avatar
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Calculation of transconductance in a MOSFET

I am teaching electronics. I have come across this formula for drain current in the syllabus that I am teaching. However, I have never seen it before. My question is where is this number -3 from ...
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Interpreting the value of transconductance shown in a MOSFET datasheet. Why was that particular value chosen to be shown?

Context: I'm a beginner in electronics, self studying MOSFETS. I'm trying to understand why the manufacturer of this MOSFET decided to provide a single particular transconductance value in the ...
Joaquin Brandan's user avatar
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how to calculate rx, ro given gx and go from XSPICE

I have a set of XSPICE data extracted from multisim as can be seen in the attached image. How do I calculate the ro and rx (base spreading resistance) given the parameters go and gx. Thanks
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Output resistance and transconductance in the calculation of NMOS common source voltage gain

For a NMOS, the transconductance gm is defined as id/vgs at a fixed VDS. However when we calculate the small signal gain of a common source amplifier, we use vds = -id x RD and then vds = -gm x vgs x ...
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Does transconductance of a NMOS in saturation vary if I double both 'W' and 'L'?

Gm for a mosfet in saturation is 2Id/Vov. Vov is constant and we expected the Id to be a constant too for both cases since Id(sat)=0.5*UnCox (W/L)(Vov^2), W/L is unchanged and there for Id should be a ...
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What makes transconductance negative?

Quote... "transconductance is -1 amps/volt" Refer to this link for the source of my question... This reference lacks the negation of A/V while this reference includes it? I'm confused...to ...
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Transconductance of MOSFET with channel-length modulation

As far as I understood, I think it could be derived as below. $$ g_m = \frac{\sigma I_D}{\sigma V_{GS}} = \mu_n C_{ox} \frac{W}{L}(V_{GS}-V_{TH})(1+\lambda V_{DS}) $$ $$ = \sqrt{2\mu_n C_{ox}\frac{W}{...
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Gmo2 from vout about differential amplificator

I'd like to know if this demostration is correct to calculate Gmo2 from vout about differential amplificator from this diagram : 1 : Gmo transconductance about Common Base configuration 2 : Gmo1 ...
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LM13700 Gain Calculation

I pulled some LM13700 OTAs from an old board and tested them. All voltages, currents, and resistances were measured. I had the expected (approximate) voltage gain using the equation \$ A=(R_2/(R_1+R_2 ...
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How do you find the transconductance of an external crystal oscillator?

I am trying to connect an external crystal to my STM32F446RC MCU. I am following this guide to check for the compatibility: https://www.st.com/resource/en/application_note/cd00221665-oscillator-design-...
Diego C's user avatar
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Transconductance value in LTSpice

I am trying to work out how to specify the transconductance value or Kn for LTspice. I have a part I can't find a suitable model for so I'll need to create one. I've tried this before and got values ...
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Can a floating capacitor terminal be used to collect electrons?

I want to collect charge from an electron beam source. For that, I'm proposing to put a floating capacitor with its bottom terminal floating and directly exposed to the electron beam gun. The top ...
Jorge Johanny Sáenz Noval's user avatar
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MOSFET triode small-signal modeling

TL;DR: Why do seemingly all treatments of MOSFET small-signal operation ignore the nonzero \$g_m\$ contribution in triode? Is the implicit assumption here that if the MOSFET is operated in triode then ...
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Modeling MOSFET Pole and Transconductance for use in Larger Overall Control System

Recently I began a project involving some active current limiting using a MOSFET and an Op Amp. It is part of a larger overall circuit involving other Amplifiers. I would like to perform a block-...
banjoeschmoe's user avatar
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Mosfet transconductance in the saturation region

what happens to the transconductance of a MOSFET in the saturation region if the gate-source voltage is less than the threshold voltage? Will the transconductance be negative since the equation is ...
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Trans-conductance of the system

What will be the effective transconductance of the system? We have an amplifier of the voltage gain of -2 and R, C connected as shown. I believe We can't judge if the system is in negative feedback ...
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Trans-conductance amplifier using CS MOS amplifier

What is the meaning of the text "Less control on input Impedance"? Why did we add CS amplifier for this purpose?
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Why is transconductance vs gate voltage graph for a mosfet not constant when drain current is a linear function of gate voltage?(in linear region)

Id=Kn(Vg-Vth)Vd in the linear region This should imply that the transconductance is constant for constant Vd(drain voltage) but the graph is something else
Aishwarya Aishu's user avatar
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Finding transconductance for common-source amplifier

I wanted to check if the transconductance formula I am using is correct when I am dealing with an amplifier that has a small signal (Vsig) and a DC signal(Vs). The schematic below is a little unclear ...
hyper electron's user avatar
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JFET resistance and transconductance

The book says the rds of the 2N8461 JFET can be varied from 100 ohm to 10Meg. I went on and tried to verify this using the equation and plug values in it from the datasheet using the minimum values ...
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MOSFET drain current equation vs on resistance

I have a very simple circuit. It’s just an n-channel enhancement MOSFET where Vgs is being driven to 9V and a relatively small 9ohm resistor sits between the 9V battery and drain terminal. The way I ...
user16378's user avatar
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the transconductance of cascade MOSFET IF channel length modulation is NOT ZERO

What would the derivation of the cascode MOSFET transconductance in small signal analysis IF THE CHANNEL LENGTH MODULATION IS NOT ZERO, as most examples for the cascode mosfet transconductance say in ...
TheSprintingEngineer's user avatar
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How does the Early effect limit the voltage gain?

As far as I understand, the Early effect increases the quiescent \$I_C\$ for a given \$V_{CE}\$. At the same time texts treat this effect as a limiting factor for the gain. Here is an excerpt from a ...
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How to experimentally calculate transconductance of an OTA?

How can I experimentally calculate the transconductance of an Operational Transconductance Amplifier given that I know the value of bias current ?
Anirban Choudhury's user avatar
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1 answer
415 views

Mathematical Model for SiC MOSFET C2M0080120D, transconductance and capacities [closed]

I am currently trying to use the model described in the paper "An Improved Analytical Model for Predicting the Switching Performance of SiC MOSFETs" in MathLab to simulate/imitate it. The paper can be ...
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Plotting G(t) of an oscillator in Cadence

I have a cross-coupled NMOS-only oscillator that has its bias voltage changing so its transconductance is also changing over time. I want to plot its transconductance (G(t)=G0-gm/2) over time in ...
Fateme's user avatar
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Constant-gm bias circuit

I am doing a study on Improvements in biasing and compensation of CMOS opamp. Do you guys know how to come up with the equation for RDS4C ?
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Error Amplifier Gain

I was studying the "SG3525" IC and its functions, and I encountered this issue: In the "Error Amplifier" section of the Datasheet, there is a parameter that named "DC trans-conductance" which it is "...
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2 votes
3 answers
492 views

Measuring transconductance of any circuit

May I know if the following transconductance measurement test circuit is correct because I am getting quite small Gm values ? I suspect that I need to use some derivative function because changing ...
kevin998x's user avatar
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Advantages/Disadvantages of high/low transconductance efficiency (gm/Id) of NMOS/PMOS

From here, it's said that a higher gm/Id results in lower current consumption (which is usually preferred in low power operation) But what other effects does a high gm/Id have? Will it have other ...
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Understanding Operational Transconductance Amplifiers

I understand the high-level function of OTAs, that they provide an output current proportional to an input voltage. But what I don't understand, and what I can't seem to find any information on online,...
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OTA design, the Gm won't go down to zero

I'm trying to simulate a pseudo-differential OTA, but the the Gm vs Vin(differential) plot I obtain seems warped. The Gm won't go down to zero for large values of Vin. attached is the circuit ...
styxies's user avatar
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Determine transconductance of a JFET given only voltage gain and internal drain resistance

I have a homework question as follows: If a JFET having a specified value of rd=100 kΩ has an ideal voltage gain of Av(FET) = -200, what is the value of gm ? As far as I know, the closest formula for ...
joshua0823's user avatar
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Common Source JFET Amplifier Gain

I would be thankful if someone could explain me what is the general formula used to calculate the gain of a common source jfet amplifier. I have the fallowing circuit: Since this circuit was taken ...
Simon Maghiar's user avatar