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Questions tagged [rdson]

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Estimating GaN HEMT junction temperature

I think it's quite a simple question, but the solution is not so obvious for me. I know the equation Tj=Ptot×Rth+Ta, the thermal resistance Rthj-a and RDSon temperature dependance come from the ...
Den's user avatar
  • 11
2 votes
2 answers
115 views

Is this setup for measuring MOSFET RDS_On correct?

I ordered some MOSFETS from AliExpress and I think I've been duped. The diagram below shows my setup: If I'm not mistake, this means that the R_DS(On) of this N-channel MOSFET is 0.042/0.62 = 67 ...
UnknownDagger's user avatar
1 vote
1 answer
768 views

LTspice - What is the best way for having Rds(on) curve of a MOSFET?

I am trying to get the Rds(on) of a MOSFET. I have tried different methods and I do not know what is the best method. There might be a method that is better than the ones I used. In practice, it seems ...
Jess's user avatar
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0 votes
1 answer
59 views

P-MOSFET Rdson values with Vgs near maximum

My understanding is that a MOSFET's Rdson generally decreases with higher absolute Vgs values within its specified range, and I typically consult datasheet curves showing Rdson vs Id and Vgs. I'm ...
JAE's user avatar
  • 55
0 votes
1 answer
192 views

DC-DC boost converter theory / principle / testing

I am trying to setup a DC-DC boost converter circuit that can convert 50-60 V DC to 86.4 V at the most current I can achieve a reasonable efficiency of say 90%. Mostly for the learning curve but my ...
Jay Dee's user avatar
  • 339
1 vote
0 answers
71 views

Mosfet Rdson inconsistency in datasheet? Or conceptual error?

I was checking the datasheet for the Allpower AP2012S and while checking the graphs to determine the Rdson in my point of operation I found what I think might be an inconsistency, however, I wanted to ...
Mateo Ardila Villegas's user avatar
0 votes
1 answer
82 views

Help solve rds for pchannel FET from this datasheet

I would like to use a pchannel FET as a voltage controlled resistor in a circuit where my voltages are between 0 and 1.1 Volts. I'm hoping to use the J175 but truthfully I am having a difficult time ...
RobMcN's user avatar
  • 165
5 votes
4 answers
1k views

On-state resistance limit in the MOSFET safe operating area figure

I'm trying to understand the upper-left corner of a typical MOSFET safe operating area (SOA) figure. Specifically why the region marked in red on the figure below, above the "Limit Rds(on)" ...
avian's user avatar
  • 341
-1 votes
1 answer
1k views

How to determine the Rds(on) from a MOSFET datasheet

I want to know the RDS(on) of this MOSFET when VGS = 3.5 V, and ID = 5 A . As you can see, the graph stops at 2.5 A. data sheet link: https://pdf1.alldatasheet.com/datasheet-pdf/view/555356/...
haithem's user avatar
  • 23
2 votes
2 answers
338 views

Precharge MOSFET safe operating area with inline resistor

I'm looking to use a MOSFET to turn on a resistive path, precharging a capacitive load. I'm considering the Nexperia BUK9608-55B, but I'm having trouble determining what my operating point is on the ...
matth's user avatar
  • 127
1 vote
1 answer
1k views

RDS measurement on P-Channel MOSFET

I want to measure the Rds-ON of a P-Channel MOSFET and I have setup the test circuit as follows: I keep the source at constant +10V and vary the step the gate voltage up in the increments of 1V. Then ...
Zaffresky's user avatar
0 votes
1 answer
166 views

How can I calculate the worst-case Tj of a MOSFET in discontinuous operation at another Tamb?

I am faced with the task to calculate the maximum junction temperature of a MOSFET in a half-bridge, having conduction losses, switching losses and diode losses. The real difficulty comes from the ...
christoph's user avatar
  • 720
1 vote
0 answers
127 views

MOSFET Gate Charge dependance on temperature at HOT, to determine charge needed to design driver?

i am designing this push and pull driver for external NMOS in my buck topology circuit. i am well aware the gate charge ( based on Cgd) i need to turn FET ON and OFF at room temperature based on ...
Narendra Mane's user avatar
0 votes
0 answers
357 views

JFET RDS(on) Matching

Quick question here - I have a circuit that originally used a 2SK30ATM-GR JFET, with an RDS(on) maximum of 800 ohms. Most of the cheap JFETs I can find have a significantly smaller RDS value, ...
zvolk4's user avatar
  • 135
2 votes
2 answers
375 views

MOSFET Vds and SOA graph

I have a question regarding the SOA graph and a low Vds voltage (below 100mV), I will get to the questions below but needed to layout some information first. I am looking at a International Rectifier ...
Suze1990's user avatar
  • 101
0 votes
2 answers
453 views

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 ...
Paumdrdo's user avatar
0 votes
1 answer
199 views

Am I calculating my shunt FET power dissipation correctly?

simulate this circuit – Schematic created using CircuitLab I'm designing an LED driver circuit that requires very fast PWM switching at a high resolution (10bit at 30khz requiring a minimum ...
flimsy's user avatar
  • 362
2 votes
2 answers
671 views

Calculate MOSFET Forward Voltage Drop

I'd like to better understand how to calculate the voltage drop between the Drain and the Source of a FET. As an example, say we have a MDD1902 N-channel FET. How would I determine the maximum ...
Tim51's user avatar
  • 99
0 votes
2 answers
472 views

MOSFET with very low Rds_on for very small current

I'm building a uCurrent Gold clone (https://www.digikey.ch/reference-designs/de/sensor-solutions/current-sensing/2637) - with a digital interface (measuring the voltage directly with a microcontroller)...
cortesis's user avatar
5 votes
3 answers
3k views

Paralleling mosfets to reduce Rds On?

This if a fairly simple question. I have some APT43M60L MOSFETs with a fairly high on resistance. They get quite hot and waste a lot of power in my induction heater. They work great but get really hot ...
ElectronicsNoob's user avatar
0 votes
3 answers
153 views

Dual N-channel mosfet Rdson value

I'm going though datasheets of some dual N-channel MOSFETs for li-ion battery protection, like 8205A or ECH8695R, for some thermal and power dissipation calculations. There are Rds(on) values, like ...
Chupacabras's user avatar
  • 5,508
0 votes
2 answers
146 views

Help needed in understanding MOSFET datasheet

I am trying to find a logic level MOSFET for 3.3V operation. In my case, I am trying to compare AOD510 & AO4402. AOD510: \$\mathrm{R_{DS(on)}}\$ @ 4.5 \$\mathrm{V_{GS}}\$ = 0.004 ohm but has no ...
Electric_90's user avatar
  • 2,162
1 vote
2 answers
1k views

Vds vs. Rds(on) on 19N10L mosfet

I measure in common source connected mosfet (19N10L) Vds about 2.4V in on state. The current is 2A. In datasheet is defined Rds 0.1ohm. Why is Vds in this mosfet so high (2.4V)? Shouldnt be Vds = 0.1 ...
user avatar
1 vote
1 answer
100 views

What is the parasitic resistance due to an IC package in a mosfet? (or any package)

How much resistance does the package of an IC contribute to the paraistic resitance of a circuit? (most applicable to mosfets)
Voltage Spike's user avatar
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