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

[rsdio at audiobanshee.com]

Mouser has 2 Metal Oxide and 116 Metal Foil resistor products in SMT, the latter from three different manufacturers. Metal oxide aren't quite as good as metal film, but are typically necessary for high wattage applications (above 1/2 W).

I don't really know whether Metal Foil is the same as Metal Film, but they are all very accurate (from 1% down to 0.01%). Values range from 5 Ohms to 75 kOhms, and power ratings from 1/10 W to 1 W. Minimum 20 V up to 220 V.


Perhaps Mouser isn't the best way to search, because they might use different terms. Looking at the Vishay.com web site, I found the following:

The Vishay Dale PSF series is metal film resistors. They do no quote noise characteristics.

The Vishay Dale WSF series is metal film resistors for power applications.

The Vishay Draloric PMM0204 series are metal film, cylindrical resistors that look like leadless resistors designed for SMT. The data sheet says NOT FOR NEW DESIGNS. I wonder if they have a replacement.

The Vishay Sfernice MSP 1 C and MSP 2 C series data sheet says that uses metal film technology.

The Vishay Draloric M25SI Fusible Thin Film Chip Resistors line is metal film on high quality ceramic. They're designed as fuses for overload at a constant voltage, so I don't know if they're appropriate for audio.

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
>