Interfacing high current leads with a PCB

[Boncuk]

Hi Andrew,

I didn't say one gate resistor is necessary for each transistor, but the resistor is a good method to get across the annoying traces between the pot and the gate pin.

On the other hand individual gate resistors won't hurt.

Here is a transistor I would recommend for high current. Using two of them is already an overkill for your application. A single transistor can dissipate 306W.

The transistor is PSMN1R6-30PL (NXP-Semiconductors). Check out the attached datasheet.

The colours at the connector outside the board indicate: black=ground, green=+12V, yellow=not used for the fan.

I use that heatsink and fan with an SLA-battery charger and the fan is on whenever the charger is on.

The software I'm using is supposedly the same as you are using. I use Eagle (version 3.55)

Regards

Boncuk

 

[Andrew Leigh]

Hi Boncuk,

thanks a lot. I will check if these are available locally.

I am slowly getting a hang of this. It would appear as if the important criteria of any Mosfet is the RdsON, the lower that is the more current can pass for the same given heat generated?

I have also noticed that 2 to 2.5W appears to be the limit for a T220 package in air with no cooling.

Would I be correct in stating the two of these device could be used with no heatsink? Just trying to confirm the answers to the maths I am learning to calc these numbers.

Thanks for the help
Andrew

"The software I'm using is supposedly the same as you are using. I use Eagle (version 3.55)"
Did not recognize the fancy resistor shape thats what confused me, it looks nice.

 

[Boncuk]

Would I be correct in stating the two of these device could be used with no heatsink? Just trying to confirm the answers to the maths I am learning to calc these numbers.

According to my calculation a PSMN1R6-30PL has to dissipate 410mW at the minimum RDS(ON), V(GS)=10V of 17mΩ with a load of 25W.

So you might get away without heatsink. I like electronics "cool" and always use overdimensioned heatsinks for my applications, never to exceed +35deg/C at 25deg/C ambient temperature. I use to fix fried eggs using a pan.

"The software I'm using is supposedly the same as you are using. I use Eagle (version 3.55)"
Did not recognize the fancy resistor shape thats what confused me, it looks nice.

Have you ever seen a resistor looking like a rectangle from the top view? I haven't till now. That's why I modified the package to look like the "real thing".

Regards

Boncuk