Do standard TO-220 washers fit an LM3886T?

[wintermute]

Hi everyone,

I'm thinking about knocking up a gainclone for a test amp, and can get LM3886T's at the right price, but I'm concerned about insulating them. (did a search and mostly people are asking whether to insulate or not, not my question).

I don't want a live heat sink, and from what I can see on the datasheet, even though it says it is a TO-220, the size is not standard, and is quite a bit wider than a normal TO-220.

Is the actual thermal plate on the back of the chip only as big as a TO-220 washer? Can I just use standard TO-220 washers with some thermal grease and be done with it

Tony.

[shusha]

Dimensions are: 17,5 x 20,02 cm. You'll easily find insulators that size. You should insulate them. Otherwise you will need to insulate heat sink from the enclosure and mount each LM on its own heatsink.

Insulators are cheap and available in every electronic shop. You will also need a plastic insulator for a screw (is it a pad? I don't know an English word for it!).

[wintermute]

thanks Shusha,

I guess the best thing is to go in and measure them none of the aussie sites actually have the dimentions of the mica washers! from what I can gather standard to-220 is 10mm wide but the LM3886T is 20mm wide...... so I thought I might have difficulty getting the right sized washers. None of the aussie sites seem to give the dimentions of the washers, and in general only have to-220, top-3 and to-3 insulation kits. maybe the top-3 would be big enough.....

edit: I think the insulator for the screw you are talking about is usually called a bush

edit2: hmmmm even to-p3 is only 15mm wide...

Tony.

[tlmadsen]

TO-220 washer is to small, but a TOP-3 will just do the job.

YOu can get washer that fits LM3886T, but they are expentive and hard to come buy.

If you use moer than one LM3886T, the best think is to buy " a sheet" and cut it so cover all you LM3886T.

Have fun

Thomas

[Vikash]

Originally posted by wintermute
can get LM3886T's at the right price, but I'm concerned about insulating them.

Are the TF's the wrong price Tony

[wintermute]

Thanks Thomas

Sheet might be the way to go, I think RS components sells sheets. I think I'll order my LM3886's then take them in to the local electronics shop and see what fits, If they don't have anything I'll order a suitable sized sheet from RS.

Tony.

[wintermute]

Hi Vikash,

Yeah futurlec has the T's for $4.66 but the cheapest I can get the TF's for is $16.00

Tony.

[TS Lo]

Hi Tony,

I use TO-3P silicon rubber insulators for my gainclone
from Jarcar (Cat. No.1174). The size just fits LM3886.

Cheers

TS

[slackman]

hi wintermute,
look into your mailbox...

i can send you some TFs ...

Michael

[wintermute]

Thanks TS Lo looks like I'll be visiting jaycar

Hi Michael thanks for the offer!! but I think I can buy them for less than it will cost you in postage (about $9 aus) and I'm buying something else anyway so the $4 postage is covered)


Cheers,

Tony.