What happend to 320K resistors ?

[Jan Audio]

Hi, something happend in resistor land.
I can not get 320K metal resistors anymore ( for a normal price )
Why did they stop making those ?

[AndyC_772]

320K is E192 range - pretty obscure values, and there's bound to be some values for which there simply isn't the demand.

Can you not use 316K instead? That's E48, should be more readily available.

[Jan Audio]

The thing is i like to make a 6-bit DAC :
5K
10K
20K
40K
80k
160k
320k

[bdunham7]

https://www.mouser.com/ProductDetail/Vishay-Dale/CMF55320K00BER6/?qs=OCLsGa2zKBtCzF2AhImE2w%3D%3D

[vad]

Use two 160k (E24) resistors in series.

[JohnnyMalaria]

Mouser sell them. e.g., https://www.mouser.com/ProductDetail/Yageo/RT0603DRD07320KL/?qs=ABvmyp11KkhJ2c1FEjGD5A%3D%3D

Or you could just use 316 + 1 + 1 + 1 + 1?

[Jan Audio]

I dont have anything SMD, searching for normal axial resistors.
Soldering more resistors is not the plan, i still have some 320K resistors, i want more.

[Jan Audio]

if i buy 100 of those 50 cent resistors, i have instant free shipping.

[JohnnyMalaria]

See bdunham7's answer. It's axial.

[wraper]

Buy 316k, that's only 1.25% difference. Unless you need extreme precision.

[Jan Audio]

Ofcourse i want the precision for a DAC,
because i could buy them some time ago i dont want those 316K.
They just disapear ?, someone has buyed them since they have nothing left.
Why not make a few to keep stock ?, is it so difficult ?

[bdunham7]

Exactly what were you buying before that you can't get now?  Are the ones I posted not what you need???  Other than '320K' what are the rest of the specs you need or had?

[JohnnyMalaria]

Ofcourse i want the precision for a DAC,
because i could buy them some time ago i dont want those 316K.
They just disapear ?, someone has buyed them since they have nothing left.
Why not make a few to keep stock ?, is it so difficult ?

Mouser has them. Granted, it's overseas but you have a very specific requirement so your options are going to be limited.

Alternatively, buy a lot of 10% or 20% 330K and measure each one. One will be 320K.

[nali]

Ofcourse i want the precision for a DAC,
because i could buy them some time ago i dont want those 316K.
They just disapear ?, someone has buyed them since they have nothing left.
Why not make a few to keep stock ?, is it so difficult ?

Just wondering, why do you need such precision when you only have 6 bits anyway?

[Siwastaja]

What's wrong with the classic R2R DAC that uses a single value of resistor?

What's wrong in putting another resistor in series?

How are you driving your resistor DAC? From standard CMOS outputs of an MCU or logic IC? 

I think the problem isn't sourcing 320kOhm resistors; it's designing a DAC. Let's start by defining your requirements for the DAC.

[asmi]

What's wrong with the classic R2R DAC that uses a single value of resistor?

What's wrong in putting another resistor in series?

How are you driving your resistor DAC? From standard CMOS outputs of an MCU or logic IC? 

I think the problem isn't sourcing 320kOhm resistors; it's designing a DAC. Let's start by defining your requirements for the DAC.

I would add one more question - what's wrong with people designing in thru-hole passives in year 2021?

[srb1954]

Ofcourse i want the precision for a DAC,
because i could buy them some time ago i dont want those 316K.
They just disapear ?, someone has buyed them since they have nothing left.
Why not make a few to keep stock ?, is it so difficult ?

Just wondering, why do you need such precision when you only have 6 bits anyway?

And why get so concerned about a little bit of error in the resistor value for the LSB of the DAC? 

You are going to need some very precise resistors for the MSB of the DAC before the error in the LSB value is even going to be noticeable.

[srb1954]

Ofcourse i want the precision for a DAC,
because i could buy them some time ago i dont want those 316K.
They just disapear ?, someone has buyed them since they have nothing left.
Why not make a few to keep stock ?, is it so difficult ?

It is actually quite difficult for the distributors and manufacturers to deal with the demand for with rarely ordered values.

A distributor is not going to want to keep a reel of very slow moving resistors on the shelf just for the occasional low volume purchaser. The solderability of components deteriorates over time so the distributor is only going to stock items that can be turned over every 6 months or faster.

The manufacturer is going to have the same problem. They are not going to keep an obscure value on the shelf just in case some distributor orders it out of the blue. More likely they will manufacture the value to order and then they will want to manufacture considerably more than a one reel quantity to justify the set-up costs for that production.

[coppercone2]

axial resistors kick ass

what suppliers get for stocking e196 is
1) people buying more parts in general in the first theme because they can get anything they need in the same kind for uniform designs, its not that much room considering the size of these places, give me a break. you need them for some engineering designs, stop forcing SMD on people for no reason other then its cheaper or desirable for YOUR process.. stop thumping the 'new testament' of SMD being better at everything, not everyone wants rice. People keep pushing vibration but there is also flex
2) respect

[wraper]

stop forcing SMD on people for no reason other then its cheaper or desirable for YOUR process.. stop thumping the 'new testament' of SMD being better at everything, not everyone wants rice.

SMD is not only cheaper but also takes less space, is faster to assemble and have less of parasitic inductance. Not to say TH parts go away, you simply cannot find most of modern parts in TH.

[coppercone2]

and whats the flex resistance of a 1206?? stiff as a man dead 2 weeks. all people keep pushing is vibration resistance and inductance, try failure mode, inspection, repair, flex,

and you can use heat sink clips nice on through holes to HIGH effect and have easy probing with the most basic of grabbers without a lab setup. you can hook on to them upside down in a panel with a flash light on your head if you wanted to while your being held upside down on a rope no problem.

[james_s]

I would add one more question - what's wrong with people designing in thru-hole passives in year 2021?

This does strike me as a bit strange. I still use them for prototyping occasionally, and might consider it for a kit aimed at total beginners but otherwise there are few reasons to use small through hole resistors. There's always the huge chunky 1206 surface mount parts for people that have poor eyesight or shaky hands.

[wraper]

and whats the flex resistance of a 1206?? stiff as a man dead 2 weeks

Who sane uses 1206 other than for parts which must be large? Even 0805 is too large for most passives.

[coppercone2]

1/4 watt

you want a 1/4 watt smd you get 1210 minimum , depending on what your customers believe

1206 is 1/8 my bad 

[wraper]

1/4 watt

you want a 1/4 watt smd you get 1206 minimum , depending on what your customers believe

You can buy 0.3W in 0805. In 1206 you can get up to 1W.  And you don't need 1/4W in 99% of cases, 1/16W or 1/8W is more than enough usually. Just because small TH resistors usually come with 1/4W rating does not mean you actually need it.