The 2SC5200 & 2SA1943 are in TO264 packages 20.5 x 26mm, I can't find any source for mounting hardware for these. Can anyone advise regarding alternatives?
Thanks,
Gordon.
Thanks,
Gordon.
How about these washers:
Kerafol Keratherm 70/50 Thermal Transistor Pad TO-247 1.4W/mK 23x28x0.25mm | Rapid Online
Kerafol Keratherm 70/50 Thermal Transistor Pad TO-247 1.4W/mK 23x28x0.25mm | Rapid Online
If they are plastic package (http://www.st.com/web/en/resource/technical/document/datasheet/CD00249630.pdf), use heatsink compound only.
For the types of 2SC5200 transistors shown in the photograph below, I use mica insulators and Aavid ThermalCote_I grease. I like to use an Xacto razor knife blade to split the mica insulators into ~ 10 mils thick pieces.
The "trick" is to buy TO3P mica insulators, which are too large. Then cut them down to size with scissors. Don't use expensive scissors because mica will dull them quickly. Here are a few vendors of TO3P size mica insulators
(Newark)
(MCM Electronics)
(little Mom and Pop electronics shops in Hong Kong, via eBay)
_
The "trick" is to buy TO3P mica insulators, which are too large. Then cut them down to size with scissors. Don't use expensive scissors because mica will dull them quickly. Here are a few vendors of TO3P size mica insulators
(Newark)
(MCM Electronics)
(little Mom and Pop electronics shops in Hong Kong, via eBay)
_
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Thanks these should be just enough to guarantee coverage and I like this supplier, they are as in their name, rapid!
Gordon.
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I think I'll go for the eBay ones as I won't be needing them immediately anyway and the eBay ones seem like a much better offer, hope they are decent! The seller has a very good rating so reckon they should be OK.
Thanks to everyone for your advice.
Gordon.
The ones linked to on eBay will be too small, check the size and your measurements.
You should get the TO247 versions, those work well for the TO-3PL package which is Tosh calls it IIRC.
You should get the TO247 versions, those work well for the TO-3PL package which is Tosh calls it IIRC.
Thankfully i noticed this when i went to order! Thank you for warning me though. 🙂
Gordon.
I have been disappointed, in planning to use oversize pads specified for smaller sizes. Some just don't give enough overlap for comfort, when you cannot see the pad edge alignment beneath the case. TO247/TO218/TOP3-n are nominal 16x20mm and though the TO264 metal heat spreader is usually only 18x22, you may need to be lucky rather than smart to receive the specified sizes with enough latitude for reliable use.
I find no problem with Chinese Ebay sources and prices so far. If you are adventurous, how about these, assuming the heatsink face is quite flat, of course: TO 264 TO 3PL 22x28mm Ceramic Insulator FOR Transistor Heatsink 22 28 1mm 5 PCS | eBay
I find no problem with Chinese Ebay sources and prices so far. If you are adventurous, how about these, assuming the heatsink face is quite flat, of course: TO 264 TO 3PL 22x28mm Ceramic Insulator FOR Transistor Heatsink 22 28 1mm 5 PCS | eBay
Keratherm and most other "soft" thermal washers are a use once and throw away.
At the prices we get charged I only use the expensive thermal washers for the very final build.
I use Sellotape as a temporary thermal washer, even for very high bias ClassA devices, while testing. And prefer to clamp rather than the offset single bolt fixing.
At the prices we get charged I only use the expensive thermal washers for the very final build.
I use Sellotape as a temporary thermal washer, even for very high bias ClassA devices, while testing. And prefer to clamp rather than the offset single bolt fixing.
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