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# Vgs Negative Voltage

25 Threads found on edaboard.com: Vgs Negative Voltage

## Drive Mosfet with 5V

Complete circuit diagram attached. Really? You have connected the gate to ground, vgs = -9V, MOSFET permanently on. If you want to further modify the schematic, please notice that vgs has to be applied between gate and source. Source node is at input voltyage level (+9 V). To switch the MOSFET off, you'll apply vgs < 0.5V respec

## SiC FETs for 170degC ambient buck converter, what is rds (on) at v (gs) =10v?

Present day SiC MOSFETs are not real sweet to drive, many need well more than 10V to turn on and a negative vgs voltage to turn off. I suggest you take a look at the GeneSiC SJT devices which can be had from Digi-Key, Mouser et al for not terrible pricing in a 175C rated grade (or you can get 250C rated, if you want to spend 10X). These (...)

## PMOS amplifier polarization

Your vgs is only 0.8V? You do not say the range of vgs the Mosfet has at the tiny current of about 9uA. Your schematic is a negative, it should be a positive with a white background. Why is Cadence so weird?

## how to calculate the ICMR of the full differential telescopic amplifier

123078 Lets say, a fully differential nmos-input telescopic amplifier, and I assume the supply is 3V, and the overdrive voltage of the M9, and M1, M3, M5, M7 is 0.5V, 0.2V,0.2V, 0.3V, 0.3V. that means the ouput swing is 1.5V for one side. and the threshold voltage for P/NMOS is 0.7V. I want to calculate the ICMR of the

Dear Sir, I have designed LNA using ATF54143 transistor, have set biasing values Vds= 3V , vgs= 568mV, and Ids= 53.9mA for the nonlinear device model of ATF54143 transistor and simulated using ADS2011.10. I have generated the layout and PCB fabricated for LNA, when I measured the fabricated PCB biasing vgs, Ids, and Vds

## Doubts regarding on the Avago ATF54143 transistor parameters

Dear Sir, I want to use my design to Avago ATF54143 transistor. When I went through the datasheet of Avago ATF54143 transistor. I am getting the following doubts. (1) He has given in the datasheet absolute maximum ratings as follows Symbol Parameter Units Abs

## Why PMOS used in LDO more than NMOS?

You can build a PMOS LDO that works within the input rails entirely, so long as you have enough negative vgs (wrt VIN) to get the on resistance you need. A NMOS LDO requires a supply above output voltage (by a fair bit) so when dropout is actually low, you need a supply above VIN. There are NMOS LDOs now, especially for the sub-2.5V high (...)

## mosfet switching safetys

P-Channel MOSFET will require a negative gate to turn on. For Vds, +ve voltage should be applied on the source, and the drain should be kept negative. Make sure that the gate voltage you are applying is greater than vgs(threshold) that is specified by the manufacturer of the MOSFET you are intending to use.

## What will be the biasing voltage for PMOS acting in saturation region?

For a PMOS just consider all the things as negative. in your case you mention Vds as 0.6V. This would mean that Drain is 0.6V higher than Source. This would be incorrect for a PMOS. What you mean to say is Vsd = 0.6V => Vds = -0.6V Vth = -0.2V Therefore, Vds + Vth < vgs < Vth i.e. -0.8V < vgs < -0.2V would make sure that the pMOS (...)

## IV characteristics for PMOS on cascade probe station

Use it like an independent PMOS, i.e. ignore its gate connection to the NMOS gate. Sweep the (negative) drain voltage with vgs as parameter, and measure the drain current.

## Power MoSFET Drain-Source Voltage

How the two MOSFETs are connected ? When you say peak-to-peak=12V you mean the vgs voltage is both positive and negative ? It could also be you are using a PWM frequency that is too high. Try to give manually 0 and 12V as vgs in order to see if the transistor alone switches correctly.

You will get many results form google using "p mosfet id vs vgs" In addition you can also download a couple of P mosfet datasheets

## negative bias to pmos.

The max vgs is specified in the datasheet (usually around 20v) , as long as vgs is lower than this voltage there is no problem. The mosfet gate doesn't draw current like the base of the transistor, there is just a gate capacitance that needs to be charged in order for the mosfet to conduct. Alex

## NMOS Vgs versus Temperature for Zero Temperature Coefficient current

vgs should be negative temperature coefficient for normal vt nmos. If it is ture, one of possibility is deplete nmos.

## Software tool for NBTI stress analysis

Dear all, here is the problem: given a set of HDL-described hardware blocks, I would like to estimate the (statistical) distribution of vgs voltage on PMOS transistors (given a predefined input set) in order to estimate the NBTI degradation. All I need for now is the number of PMOS transistors that are subject to a negative (...)

## NMOS gate at a voltage lower than source and bulk voltages

If you take the gate too far negative, and have a high drain voltage the field sum will begin to increase drain current above the zero-vgs leakage floor. Look up "GIDL". You can see this in ID-VG curves of real transistors if you take it far enough negative.

## Turn off NMOS while the source terminal is negative voltage?

Dear all, How to turn off NMOS while the source terminal is negative voltage (around -0.7v)? I have a idea that is to shift the negative voltage at the source terminal to the gate terminal in order to make vgs=0, but I don't know how to do. Anybody knows?

## Question on charge pump or negative voltage supply

Hello, all I am reading an application note as follows. 1. I was wondering how to turn off Q3 and Q4 with a voltage level translator. Q3 or Q4 is turned off if vgs,q3negative, too. Is that right and

## subthershold conduction,weak and strong inversion

Hi, Conduction current changes 10 times by change in the vgs by one subthreshold slope.The subthreshold slope of a typical device is 60-70mV. Regards, Jitendra Dhasmana.

## Question about T/R switch design topology

I believe your circuit is incomplete. Since the shunt fet is controlled by the DC vgs, and if there is a capacitor there you can not tell what the vgs is, I think you would need some resistance to ground across it. FETs usually use a negative voltage on the gate to source to pich them off. If you have a positive control (...)