Recommend SMD resistor

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mtl777

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Joined 2007
I need 4.64K SMD resistors for the circuit that controls input sensitivity of the left and right input channels of an AD converter unit. I guess these resistors must be high precision (1% tolerance or lower) in order for the left and right input channels to match very closely in level. What brands/series would you recommend? Also what type (metal film, thin film or thick film) is best?

I remember Vishay-Dale CMF or RN series were highly recommended for through hole. What do you think of soldering a small enough CMF resistor on the SMD pads instead of using an SMD one? Any drawbacks if I do this? How does the quality of through hole resistors compare to SMD?

Any inputs would be greatly appreciated. Thanks in advance! :)
 
stoc005

stoc005

Member
Joined 2007
For SMT, here is my opinion.
1. Any metal film MELF resistors, like Vishay .25W SMM0204 series. MELFs are round and can roll off your board before they are soldered down.
2. Panasonic ERA series 1210 size, .25W, .1%, 25 PPM and pricey.
3. Susuma RGH or RR series. RGH series is 0805 and .25W. RR series is 0805 and .1 W

For through hole....Panasonic ERO52C series. Small and metal film.

All are metal film.
 
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M

mtl777

Member
Joined 2007
stoc005 said:
For SMT, here is my opinion.
1. Any metal film MELF resistors, like Vishay .25W SMM0204 series. MELFs are round and can roll off your board before they are soldered down.
2. Panasonic ERA series 1210 size, .25W, .1%, 25 PPM and pricey.
3. Susuma RGH or RR series. RGH series is 0805 and .25W. RR series is 0805 and .1 W

For through hole....Panasonic ERO52C series. Small and metal film.

All are metal film.
Click to expand...

Thank you so much for these recommendations! :)
 
J

jcx

Member
Joined 2003
watch power ratings - use over rated, low TCR types for critical feedback gain setting R

but really large chips can be a reliability problem due to cracking


melf may have the dreaded steel endcaps


thin film - NiCr or TaN are ~$1 each


vishay bulk metal foil in smt >$10 each


I'm sure someone will be along to point out that the most accurate resistors may not "sound best"
 
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mtl777

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Joined 2007
jcx said:
watch power ratings - use over rated, low TCR types for critical feedback gain setting R
Click to expand...

What is TCR?

jcx said:
melf may have the dreaded steel endcaps
Click to expand...

What's the problem with steel end caps?

jcx said:
thin film - NiCr or TaN are ~$1 each

vishay bulk metal foil in smt >$10 each
Click to expand...

Man, those are expensive! I don't think I want to spend that much for resistors. :rolleyes: The $1 thin film I can manage. So you think they're better than metal film?

jcx said:
I'm sure someone will be along to point out that the most accurate resistors may not "sound best"
Click to expand...

You mean accurate but too clinical sounding? For an ADC, my preference would be to capture the source as transparent as possible, without any coloration.

Thanks! :)
 
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jcx

Member
Joined 2003
Temperature Coefficient of Resistance - a possible source of low frequency distortion with signal power heating of the resistor

steel/magnetic materials in resistor construction are pointed at by the hard core subjectivist crowd as possibly causing poor sound - as a industrial/scientific instrument designer I've never seen any other place where this is mentioned as a error source at audio signal levels - an effect can be just barely be measured at RF and 100s of watts in Ni plated connectors

I expect it to be really hard to measure distortion of the common "1% metal film" when self heating is low but the specs of thin film and bulk metal foil are even better
 
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mtl777

Member
Joined 2007
jcx said:
Temperature Coefficient of Resistance - a possible source of low frequency distortion with signal power heating of the resistor
Click to expand...

So a lower TCR value is better?

jcx said:
steel/magnetic materials in resistor construction are pointed at by the hard core subjectivist crowd as possibly causing poor sound - as a industrial/scientific instrument designer I've never seen any other place where this is mentioned as a error source at audio signal levels - an effect can be just barely be measured at RF and 100s of watts in Ni plated connectors
Click to expand...

Do you have any specific brands/series recommendations that do not have steel end caps?

jcx said:
I expect it to be really hard to measure distortion of the common "1% metal film" when self heating is low but the specs of thin film and bulk metal foil are even better
Click to expand...

Thanks for this info! :)
 
Xoc1

Xoc1

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Joined 2008
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mtl777

Member
Joined 2007
Xoc1 said:
Rhopint Stock a range of precision SMD resistors

http://www.rhopointcomponents.com/products.asp?category=RESISTORS&subcategory=Precision+(sm)

I have some old Rhopoint metal foil resistors from when they were rated at 5ppm (current spec is 0.14ppm!). They ones I have are magnetic. They sound good to me, but they were horrendously expensive!
These days, the thin film resistors rated at 10ppm are good enough for most precision circuits.
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Thanks, Rhopoint sure has good high precision resistors in their product line! One more high quality option to add to my list. :)

Anyone, I have a question about MELF resistors. What's the reasoning behind their cylindrical shape? I would think that a flat surface would make for more contact area (hence better for soldering) than cylindrical. So why cylindrical?

I would also like to know the color coding of MELF resistors. The resistors I am trying to replace are MELF with 4 bands. They are still in the circuit and I would like to confirm the value I read from my DMM with the value based on their color coding.

Thanks! :)
 
stoc005

stoc005

Member
Joined 2007
MELFs were the among the first SMT parts. Since they had a round body, they were manufactured a lot like the TH parts except the end caps with leads were replaced by just end caps. Some semiconductor diodes started out as MELFs too as TH parts shifted to SMT. MELF resistors use the same color code as the leaded parts. 4 colors? Probably 10-->5% parts. 1%er use 5 bands, I think. Same color code as the old carbon comp. Allen Bradley resistors of old.

Flat SMT resistors are "new". Made on ceramic slabs and cut to size, value trimmed w/ a laser and coated for protection of the resistive element. Metal film is not the most common resistive element. Thin and thick film is common.
 
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mtl777

Member
Joined 2007
stoc005 said:
MELFs were the among the first SMT parts. Since they had a round body, they were manufactured a lot like the TH parts except the end caps with leads were replaced by just end caps. Some semiconductor diodes started out as MELFs too as TH parts shifted to SMT. MELF resistors use the same color code as the leaded parts. 4 colors? Probably 10-->5% parts. 1%er use 5 bands, I think. Same color code as the old carbon comp. Allen Bradley resistors of old.

Flat SMT resistors are "new". Made on ceramic slabs and cut to size, value trimmed w/ a laser and coated for protection of the resistive element. Metal film is not the most common resistive element. Thin and thick film is common.
Click to expand...

The resistor is actually 5 bands (it's hard to see the first yellow band). The color coding is Yellow, Blue, Yellow, Brown, Brown for which the value is confirmed as 4.64K 1% according to this calculator. Thanks a lot! :)
 
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BrianL

Member
Joined 2002
I would avoid the Dale "CRCW" 'thick film' SMT resistors and the like from other manufacturers. The 'thick film' was known as 'carbon film' in through-hole resistors and is not the best for audio; excess noise among other problems. These thick film resistors are the common go-to parts for 1% SMT resistors, though you generally didn't see through-hole 1% resistors made of thick (carbon) film. I guess such are the improvements in manufacturing processes.

In addition to the Susumu units mentioned, I'd recommend the Vishay/Dale TNPW series. I also hear that IRC (?) has a TaN film SMT series that is available at Mouser, again supposedly good. All these are 'thin film', i.e., metal film. They are much better though you pay more, as noted, because you generally have to buy 0.1% tolerance units from distributors. Also, if you study the TNPW datasheet, you'll see that you are better off sticking to 1206 (or bigger) sizes for noise reasons. I don't know if this is true for other brands. However, power concerns and hand assembly may dictate the 1206 size vs. smaller sizes.
 
Xoc1

Xoc1

Member
Joined 2008
Mini Melfs

I aways found mini melf surface mount resistors to be good for small scale production (Pick & place). The resistors tend to centralise on the pads quite nicely in the reflow oven. The other advantage is being round, you can not fit them upside down! You don't need to spend any time flipping them the right way up in the component trays before placing them on the PCB:D
 
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mtl777

Member
Joined 2007
BrianL said:
I would avoid the Dale "CRCW" 'thick film' SMT resistors and the like from other manufacturers. The 'thick film' was known as 'carbon film' in through-hole resistors and is not the best for audio; excess noise among other problems. These thick film resistors are the common go-to parts for 1% SMT resistors, though you generally didn't see through-hole 1% resistors made of thick (carbon) film. I guess such are the improvements in manufacturing processes.

In addition to the Susumu units mentioned, I'd recommend the Vishay/Dale TNPW series. I also hear that IRC (?) has a TaN film SMT series that is available at Mouser, again supposedly good. All these are 'thin film', i.e., metal film. They are much better though you pay more, as noted, because you generally have to buy 0.1% tolerance units from distributors. Also, if you study the TNPW datasheet, you'll see that you are better off sticking to 1206 (or bigger) sizes for noise reasons. I don't know if this is true for other brands. However, power concerns and hand assembly may dictate the 1206 size vs. smaller sizes.
Click to expand...

Thank you for your detailed reply! :) I will be getting size 1206 or 1210. I would have preferred Vishay/Dale TNPW but they're out of stock at DigiKey. Susumu is available. Is Susumu just as good as Vishay/Dale?
 
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Berny

Member
Joined 2006
MMB 0207 or RG-series...

Working on a new stepped attenuator, I was wondering if anybody would have good experience with certain SMD resistors... currently I would go with

MMB 0207 from Vishay / Beyschlag or
RG-series (1206) from SUSUMU

you can get both easily from Mouser...

Any input is welcome..!
 
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