[sdiy] Need a TO220 thermo pad that can withstand 130vdc without arcing..

[Didrik Madheden]

Oops, I spoke too soon. Lower is worse. But I still think ChatGPT did
a reasonable job of giving a big picture overview of products in this
case. Especially the second answer doesn't seem sigh-worthy since it
has the correct values right out of the datasheet.

On Wed, 29 Jan 2025 at 23:54, Didrik Madheden <nitro2k01 at gmail.com> wrote:
>
> What's the sigh about? The answer didn't seem to contain any too
> egregious errors for that product.
> Breakdown Voltage: >4kV seems like a reasonable answer when there are
> two variants, of which one exceeds that figure, and the requirement
> was one order of magnitude lower than either of the product variations
> anyway.
> Thermal Conductivity: 1.1 W/m-K seems like a reasonable answer when
> the product exceeds this specification at 0.9 W/m-K according to the
> datasheet. (1.1 W/m-K is probably a real figure too that it picked
> from somewhere online. Perhaps for some slightly different test
> procedure, such as lower pressure than specified in  ASTM D5470.)
> The corrected answer seems to contain values copy pasted directly from
> the datasheet. I'd say ChatGPT did a reasonable job, actually.
>
> On Wed, 29 Jan 2025 at 22:00, Ben Stuyts via Synth-diy
> <synth-diy at synth-diy.org> wrote:
> >
> > And upon checking the Sil-Pad and pointing out that the specs were in error:
> >
> > "Apologies for any confusion in my earlier response. Upon reviewing the specifications for Bergquist Sil-Pad 400, here are the accurate details:
> >
> > Breakdown Voltage:
> > 0.007-inch thickness: 3,500 VAC
> > 0.009-inch thickness: 4,500 VAC
> > Thermal Conductivity: 0.9 W/m-K
> > Operating Temperature Range: -60°C to +180°C
> > Given your requirement for a thermal pad that can withstand 130 VDC without arcing, the Sil-Pad 400's breakdown voltage ratings are more than sufficient. For instance, the 0.007-inch version can handle up to 3,500 VAC, which is significantly higher than 130 VDC. Additionally, this silicone-based pad does not require any thermal compound, aligning well with your preferences.
> >
> > Therefore, Bergquist Sil-Pad 400 should be a suitable choice for your application.”
> >
> > Sigh…
> >
> > Ben
> >
> >
> > On 29 Jan 2025, at 21:51, Ben Stuyts <ben at stuyts.nl> wrote:
> >
> > I’m having fun asking these kind of things on ChatGPT 4o, so beware, the following is unverified :-)
> >
> > “For a TO-220 package that needs to withstand 130VDC without arcing and without using mica or thermal compound, silicone-based thermal pads are an excellent choice. These pads provide electrical insulation while maintaining good thermal conductivity.
> >
> > ### Recommended Options:
> > 1. **Bergquist Sil-Pad 400**
> >    - Breakdown Voltage: >4kV
> >    - Thermal Conductivity: 1.1 W/m-K
> >    - Operating Temperature: -60°C to +180°C
> >    - No additional compound required
> >
> > 2. **3M 5590H**
> >    - Breakdown Voltage: >5kV
> >    - Thermal Conductivity: 3.0 W/m-K
> >    - Operating Temperature: -60°C to +150°C
> >    - Self-adhesive and no compound needed
> >
> > 3. **Keratherm Red T-441**
> >    - Breakdown Voltage: >6kV
> >    - Thermal Conductivity: 1.8 W/m-K
> >    - Operating Temperature: -40°C to +200°C
> >    - High electrical insulation and no compound required
> >
> > These materials are widely available from electronics distributors like Digi-Key, Mouser, or RS Components. When choosing a thermal pad, ensure that it meets your thermal dissipation needs in addition to the voltage requirements.”
> >
> > Ben
> >
> >
> > On 29 Jan 2025, at 19:58, Jean-Pierre Desrochers via Synth-diy <synth-diy at synth-diy.org> wrote:
> >
> > Need a TO220 thermo pad that can withstand 130vdc without arcing..
> > I sillicon made type that does not need any compound would do best.
> > No mica/compound stuff.
> > I searched on Digikey and they have a lot available but nothing stated
> > about their voltage breakdown..
> >
> > Any idea ?
> >
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> >
> >
> > ________________________________________________________
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>
>
>
> --
> /Didrik



-- 
/Didrik