[sdiy] SMT choices comparable to 1/4 metal film TH

[David Moylan]

You did the leg work, Brian, so the thanks go to you!

Dave

On 07/19/2017 11:28 PM, rsdio at audiobanshee.com wrote:
> For those who are interested in SMT metal film, Vishay responded to my query in less than two hours.
> 
> The recommendation is to use the PSF series, which are nickel-chrome. Vishay quoted noise levels typically less than 0.1uV/V, although I wish they would put that in the data sheets. The PSF data sheet points out that the PTF series is the leaded version of the same resistors, in case you want to breadboard or prototype with the same technology in through-hole.
> 
> Other details: Size is 2012 for the 1/8W 200V epoxy package in 15 to 100kOhm. 4527 for the 1/4W 300V thermoplastic package in 15 to 500kOhm. These seem very large, so perhaps the MELF option is better for some projects. Thanks to Byron for suggesting MELF and mini-MELF, although I haven't researched those yet.
> 
> Mouser has these in their extended database, but does not stock them, asking that customers call for a quote. Digi-Key doesn't list them at all, so they may be difficult to source.
> 
> By the way, thanks for asking the question, Dave. I'd been meaning to do this research for a while, because I had the same questions. You just provided the nudge that I needed to look into it more thoroughly. If anyone has more to add, please reply.
> 
> Is there any reason you specified 1/4W, Dave? Is that a minimum wattage, maximum, or an exact value that is needed? The reason I ask is that the PSF is 1/8W in the large package and 1/4W in the even larger package.
> 
> Brian
> 
> 
> On Jul 19, 2017, at 2:43 PM, rsdio at audiobanshee.com wrote:
>> The Vishay Dale PSF series is metal film resistors. They do no quote noise characteristics.
>>
>> Elsewhere, for their leaded metal film resistors, Vishay quotes "low noise" as less than 1.5 µV/V at resistances above 1 MΩ. I'd love to see a similar noise spec for any of these SMT options.
>>
>> I'm writing Vishay now to get their recommendation…
>>
>> Brian
>>
>> On Jul 18, 2017, at 5:51 PM, David Moylan wrote:
>>> On a side note, anyone know the state of SMT resistors these days?  Are there choices that are as good as 1/4 watt metal film through hole parts for noise performance?  Googling only seems to turn up older articles and discussions.
>>>
>>> Dave
>>
> 
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