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Thermal resistance of IRLR2908PbF MOSFET

Level 1
Level 1

Hello, I have a question abouot the Junciton-to-ambient thermal resistance of IRLR2908PbF MOSFET:

The datasheet specifies 40 °C/W referring to a note at the end of the document:

The note states that this value is valid "When mounted on 1" square PCB (FR-4 or G-10 Material)." It also says: "For recommended footprint and soldering techniques refer to application note #AN-994"

Here is my question: Is the note referring to a 1 in^2 copper pad below the device (as AN-994 recommends) or is it only the area of the PCB with the device mounted in a minimum footprint?

Best Regards.

1 Solution
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Re: Thermal resistance of IRLR2908PbF MOSFET

Moderator
Moderator

Hi there,

this is the area of the PCB, and the Mosfet will be sitting inside this area on the footprint that is cu pad.

you can also check the mosfet maximum area, that is E*H = 0.265*0.410 = 0.10865 inch^2 which is less than 1 inch^2.

Thanks.

2 Replies
Attachments are accessible only for community members.

Re: Thermal resistance of IRLR2908PbF MOSFET

Moderator
Moderator

Hi there,

this is the area of the PCB, and the Mosfet will be sitting inside this area on the footprint that is cu pad.

you can also check the mosfet maximum area, that is E*H = 0.265*0.410 = 0.10865 inch^2 which is less than 1 inch^2.

Thanks.

Re: Thermal resistance of IRLR2908PbF MOSFET

Level 1
Level 1

Alright, thank you for the support!