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Questions tagged [nmos]

A n-channel metal-oxide semiconductor (nMOS) transistor has n-type carriers in the channel. A positive voltage on the gate turns inverts the substrate (PWell) creating the channel and turning the device on. The term may also be used to describe logic circuits built around nMOS transistors.

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N-Mos failing short on my PCB

I'm currently testing a PCB I designed. One of the MOSFETs, Q5, failed yesterday for the 3rd time, and I haven't managed yet to find out why. Main facts: N-channel MOSFET: CSD19538Q2T Rated (never ...
Sandro's user avatar
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6 votes
1 answer
563 views

Will this over-voltage protection circuit work?

I am designing a PCBA that is powered from an AC adapter supplying + 19 VDC to the circuit. I want to add a protection against over-voltage, let's say up until + 24 VDC. I came up with the following ...
uz3il's user avatar
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3 votes
1 answer
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Voltage drop in NMOS inverter with enhancement load

In the enhancement load NMOS inverter, why is the voltage drop across M2 at least equal to Vth when VIN is low ? Is it because for M2 when VIN is low the voltages VGS = VDS, so VDS > VGS - Vth and ...
S214ky's user avatar
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1 vote
1 answer
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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 ...
wolff's user avatar
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2 answers
130 views

How do you justify energy band bending in an unbiased MOS Capacitor?

Here is a MOS Capacitor: (Image source: Chapter 5 of Modern Semiconductor Devices for Integrated Circuits by Dr. Chenming Hu) Now lets consider the idea that the gate voltage is held at 0V, just like ...
McSuperbX1's user avatar
1 vote
2 answers
113 views

Why simulation of single NMOS/PMOS on LTspice has big difference with manual calculation using Level 1 Standard Parameters?

I am researching the mode of operation on PMOS and NMOS using Level 1 standard parameters. This is the information of the NMOS circuit to be designed. Using transistor model level 1 parameters, ...
CJ. T's user avatar
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1 answer
54 views

How to interpret MOSFET connections and voltages

I have a few simple question about MOSFETs on how to interpret their symbols and how the pins and gate voltage are defined. • I see symbols with the Source shown on the top and Drain on the bottom, ...
McKendrigo's user avatar
1 vote
1 answer
113 views

How to determine rise and fall times of MOSFET

Rise and fall times of a PWM switching MOSFET must be paid attention because too slow switching times will decrease the efficiency and too fast will cause ringing. I want to know how to choose a rise ...
CaveScientist's user avatar
0 votes
0 answers
36 views

Transistor failure in multi channel high frequency AC signals

[Intro] To begin with, I am an undergraduate electrical engineering student working on my senior project. I wanted to make a wireless charging pad like that of Tesla's wireless charging platform and ...
Martin's user avatar
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0 votes
1 answer
47 views

Driving NMOS source with a separate power supply

I am trying to see whether I can turn on 28 V voltage rail from a 5 V input signal using an N-channel MOSFET (NMOS). I am using IRF530N for now which has a threshold voltage of 4 V. I just modeled it ...
nmr's user avatar
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2 votes
1 answer
323 views

Will my gate driver work for this situation?

This is my own design, I did a gate driver for the MOSFET. Would this design work, or should I instead use a gate driver IC?
İbrahim İpek's user avatar
1 vote
0 answers
25 views

A simple NMOS circuit simulation. Is there a way I can use KCL to find Id instead of doing Id equation?

I know the traditional way to solve this, you find Vgs then you try to find Id. But for this circuit, we already can figure out the current flowing through the 2K and 3K by doing KVL(assuming I1). Is ...
Pococurante Bird's user avatar
1 vote
1 answer
27 views

is Vov of a nMos always VGS - Vt?

Looking at this graph from Analog Circuit Design Discrete and Integrated by Sergio Franco, is it always true that Vov = VGS - Vt? or is this only true at pinchoff point?
user364328's user avatar
1 vote
1 answer
53 views

Reconciling High Drain Voltage with Typical V_BE Drop in nMOS+PNP IGBT Configuration

I'm examining two design methodologies for IGBTs (Insulated Gate Bipolar Transistors) and have encountered a puzzling issue regarding the drain voltage in the nMOS part of an nMOS+PNP IGBT ...
Qiu Junpeng's user avatar
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0 answers
30 views

Multism simulation for NMOS type circuit, why I am not getting the expected graph?

I am trying to simulate my circuit for one of the question problems. The question looks like this I have written a MATLAB script to see the expected graph ...
Pococurante Bird's user avatar
0 votes
1 answer
190 views

Why is this LDO circuit not working?

I am trying to generate 5 V with this circuit for a load of 100 mA with a 2% tolerance in the output voltage. I don't want to use LDO ICs due to various reasons. My intention here is to enable/disable ...
Embedded Enthusiast's user avatar
0 votes
2 answers
246 views

What is the difference between an N-MOS FET and a tri-state buffer? [closed]

Is an N-MOS FET an equivalent of a tri-state buffer, where the source is the input, the gate is the enable, and the drain is the output?
Sny's user avatar
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0 answers
55 views

Finding the mode of a MOSFET

I'm trying to determine the state of MOSFET \$T_1\$ in the following circuit: We are given that the threshold voltage \$V_\mathrm{T}\$ is \$1.5\ \mathrm{V}\$ and that every voltage source is \$5\ \...
Sam's user avatar
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1 vote
1 answer
161 views

CMOS (Energy Supply of voltage) [closed]

Can someone please explain why, when \$ln\$ is transitioning from low to high, the energy supplied is \$C_{vdd}\cdot V_{dd}^2\$?
Timothy Garott's user avatar
0 votes
1 answer
194 views

PMOS configured in common gate

This is an NMOS configured in common gate: I am trying to understand what a PMOS configured in common gate would look like. Would Vin and Vout be reversed in this case? So, would VDD be connected to ...
c.leblanc's user avatar
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126 views

How is the total gate charge of a MOSFET affected by the temperature?

For P- and N-MOSFETs, Vgsth will decrease (in absolute value) when the temperature rises. What is the impact of the temperature on the total gate charge for P- and N-MOSFETs? What is the order of ...
Rémi Baudoux's user avatar
1 vote
0 answers
119 views

Is there a common N channel MOSFET with Pin1: Gate, Pin2: Drain and Pin3: Source?

I have designed a circuit in which I have used a BSS138 N channel MOSFET as a switch to turn on a 12V 50mA load from a GPIO. During the schematic design in KiCad, I have chosen the wrong symbol. These ...
WhiteShark's user avatar
0 votes
1 answer
119 views

How to make a power switch using MOSFETs?

I am stumped on trying to create a circuit that, through an enable of 3.3V will let +18V go to the load or prevent it from doing so. This is my current approach. I know the pullup resistor should not ...
Noel's user avatar
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2 votes
1 answer
233 views

How can I take parameters from power NMOS and power PMOS transistors and translate these into LTspice simulations?

I am trying to simulate NMOS and PMOS power transistors in LTspice, but I keep getting error messages about the NMOS being duplicate. Some of the earlier LTspice file is here. I am trying to have a ...
Stephen Elliott's user avatar
3 votes
3 answers
149 views

Is it always given that ground has lower resistance than output even If output is far closer in an inverting nmos? [closed]

Currently I'm learning about MOSFETs (N-MOS and P-MOS) --basically how a transistor works. My question is why does the current always prefer the grounding output even though it is further away than ...
Callidus's user avatar
0 votes
0 answers
45 views

Inverting MOSFET drive circuit, is my scheme correct? [duplicate]

I am an automotive engineer student, building an inverting MOSFET driver (where a MOSFET drives and controls another MOSFET, Vin low -> Main MOSFET closed, Vin high -> Main MOSFET open). My ...
Duy Nguyen's user avatar
3 votes
4 answers
2k views

Alternative to MOSFET transistors as a switch

I am looking for a 3-legged component that can be used as a switch as an alternative to an NMOS transistor. My circuit currently looks the following: - simulate this circuit – Schematic created ...
Carl's user avatar
  • 4,145
1 vote
3 answers
860 views

Bootstrapping circuit vs. charge pump for high side switching

I am designing a circuit where I need to do some high side switching to turn on/off the power to a circuit (part of some protection circuitry). This switching is actually very slow and only occurs ...
Samuel Snerden's user avatar
0 votes
1 answer
58 views

Channel Length Modulation in mos

The follwoing is a screenshot from youtube. According to the model on the left, it's easy to get $$I_{DS} = I_{DSAT} + \frac{V_{DS}} {\frac{1} {\lambda I_{DSAT}}} = I_{DSAT} + \lambda I_{DSAT} V_{DS} ...
kile's user avatar
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2 answers
61 views

Io of NMOS in small signal analysis

The question is almost 7 years old and a few people seemed to be interested in this question. But the person who had posted the question said it's from textbook. I have doubt whether \$I_o\$ it's ...
kile's user avatar
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3 votes
1 answer
154 views

How to make fast CV/CC transition in linear NMOS regulator?

I want to design a linear regulator based on NMOS with CC/CV capability. I made a circuit with two separate loops (CC and CV), each of which is stable. The problem is in the transition moment when the ...
Vasiliy's user avatar
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1 vote
2 answers
496 views

How to make a PMOS work as a constant current source?

I have a circuit in which, the PMOS is biased to a voltage source, the gate voltage, V1, of the NMOS below varies based on the functioning of the analog circuitry before. Because of this, the current ...
Siva Sandilya's user avatar
1 vote
0 answers
90 views

Electric-lock control via NMOS matrix

Currently I am working on the design that allows to control 8x8 electric lock matrix via PIC16F877A. As in comments for somebody it was not obvious (btw it was mentioned) I am using 64 electric locks ...
Alioth's user avatar
  • 13
0 votes
3 answers
276 views

NMOS as a low side switch

I am trying to use an NMOS(2N7000BU) to "turn off" the LM350 voltage regulator. I have an OR gate going into the gate of the mosfet, so either input will turn it off. The hope was to ground ...
Max's user avatar
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0 votes
1 answer
44 views

Can we use NMOS to drive WS2812

My ESP32 control circuits all use NMOS for external control. I wonder if the data control of WS2812 can be driven via NMOS?
murarduino's user avatar
11 votes
3 answers
1k views

What does a thick MOSFET symbol mean?

I have come across a bag of about 5,000 n-type MOSFETs (2n7000), and I figured the best thing to do with them is to build a 6502. I found a diagram of the nMOS 6502 layout But I am confused as to ...
EvanTheGamer's user avatar
1 vote
1 answer
153 views

Mosfet Linear Region LTspice simulation

I have a question regarding a mosfet simulation I am trying to perform. Here is the circuit in question. We can see that Vd=1kV , Vs=0V and Vg=10V(it is a pulsed source) Now to my understanding I ...
DRF's user avatar
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1 answer
247 views

the inverter switching point

As we know the mobility of the "nmos" device is 3x greater than "pmos", and when we want to correct the switching point of an inverter for vdd/2 we usually change the W of the &...
Vahe Armenakyan's user avatar
3 votes
1 answer
201 views

N-channel MOSFET fails as an inrush controller

We have designed a inrush controller using the LTM9100 controller. The LTM9100 basically controls the ramp rate of the gate voltage, which in-turn controls the raise time of the DC bus across the load....
AK47's user avatar
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1 vote
2 answers
82 views

MOSFET not saturating when Vds > Vgs - Vth

According to Wikipedia, the drain current (\$I_d\$) should stay relatively constant when \$V_{ds} > V_{gs} - V_{th}\$: (By User:CyrilB - File:IvsV_mosfet.png, CC BY-SA 3.0, https://commons....
glibg10b's user avatar
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0 votes
1 answer
45 views

R5613L understandig what MOSFET to use

I want to add a battery-protection to my circuit including a switch to disconnect the battery from the rest. I found the R5613L from Nisshinbo (Manufacturer product site with datasheet). On page 26, ...
Lyoner's user avatar
  • 339
0 votes
1 answer
61 views

Gate-source connected MOSFETs for voltage division

Currently, I am engaged in the design of a Thermal Shutdown circuit for an LDO regulator. In this endeavor, I have obtained a circuit schematic from a senior colleague, which utilizes three NMOS ...
Arnab Deb's user avatar
5 votes
3 answers
720 views

NMOS current is negative for a very short time when turning off

I am designing a circuit that uses the 2n7000 NMOS as a switch, controlled by a digital I/O pin from an Arduino Micro. I made a simulation in LTspice, and I notice that when the NMOS is turning off ...
Carl's user avatar
  • 4,145
4 votes
1 answer
215 views

LTspice Half bridge current spikes

I simulated a half bridge with two NMOS and at every switching event a current spike up to 1.2 A in the voltage source V4 occurs. I used a resistor as load because with any inductive or capacitive ...
hanss's user avatar
  • 147
1 vote
1 answer
83 views

NMOS is high when gate is low

I’m trying to simulate DRAM with N-MOSFETs with row and column selecting logic. When I select my column, which is connected to the source of an N-MOSFET, the N-MOSFETs in that column all turn on, even ...
Sss's user avatar
  • 11
3 votes
1 answer
82 views

Transient Negative voltage on NMOS causing channel to open?

This is my first post here. I am an electrical engineer looking to cure my madness because a 2N7002 NMOS is doing things I cannot explain. If you look into the attachments, you will see some screen ...
jdavis's user avatar
  • 31
0 votes
1 answer
54 views

Parameter \$k\$ for MOSFET

Is the parameter \$k\$ used for the whole circuit or for every MOSFET in the circuit? For example the circuit has 2 MOSFETS and \$k = 1mA/V^2\$. If I want to find the \$Id_1\$ and \$Id_2\$, is k = 0.5 ...
mama b's user avatar
  • 83
0 votes
1 answer
344 views

How to shift 3.3V to 5V with 3.3V provided only

I am trying to control 5V LED using ESP32's 3.3V GPIO. I researched voltage shifting using NMOS but could not get it to correctly output 5V when simulated in Tinkercad. Is it possible to accomplish ...
Megool's user avatar
  • 107
3 votes
0 answers
56 views

Which parameters should be compared to to replace N-MOSFETS with different package but with same pin functionality?

Since NTZD3154N is used a lot in my design, and I have BSS138PS only for used for one circuit, I want to replace BSS138PS with NTZD3154N in the following DP++ Auxiliary Conversion Block: Note: This ...
Firas Abd El Gani's user avatar
0 votes
0 answers
19 views

What are NMOS level 1 CV equation and its main parameters?

I was asked to perform MOSFET CV modeling. I looked through some papers, but I still can't clarify what the CV model equation for a level-1 NMOS is, and I am also not sure what its main parameters are ...
Ko Stuart's user avatar

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