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57 views

How to calculate MOSFET temperature increase in PCB

I want to calculate MOSFET(DATASHEET) temperature increase for PCB. MOSFET - FDD86250_F085-D Totally 13 MOSFET's will be mounted in PCB. At the same time, maximum 8 MOSFET's will be used in PCB 1, ...
4
votes
2answers
46 views

POWER MOSFET - Thermal Design

i have some doubts about with this thermal design? first, the calculations and infos: My load (a motor) uses an average current of 7A, I could not measure the current peak at the beginning of the ...
2
votes
2answers
55 views

Temperature specificiations on MOSFET Safe Operating Area

Here's a SOA graph: What I don't fully understand is the notes area at the bottom: *Notes: Tc=25°C Tj=150°C Single pulse Every MOSFET datasheet seems to have a similar set of notes,...
0
votes
2answers
69 views

Thermal calculation in case of duty cycle for a mosfet

For a multiplex LED matrix, I am intending to use two ULN2803's as sink source for 16 times 20 mA per column (channel). However, maybe I will try a test with 100 mA LEDs (10% duty cycle). For that I ...
0
votes
1answer
50 views

How do I exactly calculate the amount of heat generated in MOSFET?

I am using two IRFP260N MOSFETs (datasheet) in parallel for my application. I am using it to drive a motor rated at 24VDC and consumes 8 to 10 Amps. I found some answers here and calculated the ...
1
vote
4answers
166 views

MOSFET thermal resistance

I am trying to calculate the total thermal resistance of my FET to see what heat sinks are required, are the following calculations correct? $$ Power = \frac{T_{jmax} - T_a}{\theta_{JC} + \theta_{CA}}...
3
votes
1answer
156 views

MOSFET mechanism of failure: was it the heat?

I am debugging a failed MOSFET (IRF6662), and in the process of doing so, am having difficulty understanding fully the thermal behaviour of the FETs. Two FETs used for DC switching both failed short ...
0
votes
2answers
370 views

MOSfet thermal design: die-to-package always DRAIN?

All the MOSfet chips seem to have substrate = DRAIN, which means that the heat-dissipation path goes that way. It is assumed that the package DRAIN pin would conduct away most heat from the package to ...
0
votes
1answer
343 views

MOSFET pwm circuit question

Good day, I have duplicated this circuit using a 40106 hex inverter to drive a motor using pwm. The only difference in my design was to switch out the transistor stage for an Irfz34n MOSFET. The ...
3
votes
2answers
229 views

RDS(on) of DMN3010LSS MOSFET transistor

I am a bit confused about Figures 3 and 4 in the datasheet of the DMN3010LSS MOSFET transistor: Why do they show how the Rds(on) varies as a function of the ambient temperature TA? I thought that the ...
-1
votes
2answers
656 views

MOSFET power wattage

I am analyzing the thermal dissipation of the FDB33N25 MOSFET - datasheet The procedure I usually follow is as stated: $$I_{d} = 15~A (requirement)$$ $$R_{ds} = 92~m\Omega$$ $$\Theta_{ja} = 62,5~K/W$...
0
votes
2answers
79 views

what is the real DC power dissipated by an inductor that is pulsed on off

A meter indicates a higher DC power being delivered to a circuit consisting of an inductor switched on and off by a MOSFET on both the high and low side, than the heat measured by a thermistor. The ...
6
votes
2answers
432 views

MOSFET Circuit Design and Thermal Considerations

I'm a newbie at EE, and just I wanted to verify that the design I came up with for a MOSFET circuit that drives a 12V 500mA water pump will work. I'd also like to confirm I can run the N-Channel ...
4
votes
1answer
1k views

Cooling for D2PAK dissipating 30W?

I'm designing a board with some MOSFETs that dissipate a fair amount of power. The best device (low Rds and low Qg) available in this scenario would run at 30W max. This is available in D2PAK and TO-...
5
votes
1answer
231 views

Routing LFPAK MOSFETs

I am routing a PCB with MOSFETs in LFPAK (aka SOT-669, Power SO8) packages for the 1st time. They look like D2PAK. The manufacturer, NXP, advises to draw identical polygons on top and bottom sides, ...
3
votes
4answers
669 views

How to heat up MOSFET within seconds?

I'm using low power MOSFETs (N channel-STP4NK60ZFP and P channel- IRF9530). The aim is to build a demo kit for students to study the thermal characteristics of MOSFET at variable frequencies and duty ...
0
votes
2answers
336 views

How to use MOSFET thermal data for simulating in software

I have a MOSFET (irfb7434pbf) acting as load switch in a circuit. The usual operation is well within the SOA region, but, on situations where the load would short circuit, the MOSFET is set to limit ...
5
votes
3answers
7k views

MOSFET heat calculation question

I am using the FQP30N06L MOSFET: http://www.fairchildsemi.com/ds/FQ/FQP30N06L.pdf. As far as I understand the data sheet, if I connect 5V to the gate and run 2A through drain to source then with a \$...
6
votes
3answers
1k views

Apparent inconsistency of MOSFET power rating in datasheet: SOA v. max power

I am trying to use an IPP114N03L G (datasheet). I calculated the maximum power it could handle as follows: From the first two pages of the datasheet: Rthjc = 3.9K/W Tj(max) = 175C Assuming I can ...