user48418: I have three MOSFET in a row, each separated about 2.5mm apart with the backs facing each other. Is this a good idea?
N.B
Each MOSFET will be sinking 20mA and 60 mA in total for all three MOSFET. I am using an IRF540. The schematic below is for ONE MOSFET.


user2881: Power dissipation is only a couple of milli-watts. So heat is not an issue. 
Just make sure the metal tabs can’t touch each other. Personally I might add some Kapton tape. Electrical tape would work in this case, but feel wrong to me. 

48418: <p>I have three MOSFET in a row, each separated about 2.5mm apart with the backs facing each other. Is this a good idea?</p>

<p>N.B
Each MOSFET will be sinking 20mA and 60 mA in total for all three MOSFET. I am using an IRF540. The schematic below is for ONE MOSFET.</p>

<p><a href="https://i.stack.imgur.com/2wMYS.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2wMYS.png" alt="enter image description here"></a></p>
 2881: <p>Power dissipation is only a couple of milli-watts. So heat is not an issue. </p>

<p>Just make sure the metal tabs can’t touch each other. Personally I might add some Kapton tape. Electrical tape would work in this case, but feel wrong to me. </p>
