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

[Ben Stuyts]

My “Sigh” was in response to the fact that I had to point out that the initial spec for the Sil-Pad was wrong. (And I did not check the others.) I find this happens a *lot* with LLM’s. They can definitely point you in the right direction, but always verify.

That said, I really like using them when I have to code in some language that I’m not fluent in, like PHP, Javascript, etc. And I’m amazed that it actually knows about a language like Modula-2 which I use in some products. (Which I know very well.)

Ben

> On 30 Jan 2025, at 00:03, Didrik Madheden <nitro2k01 at gmail.com> wrote:
> 
> 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
>