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Adding 3.3v to pci (Beta)

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Reply 60 of 82, by Sphere478

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I'd like to add a linear regulator to this design. Any suggestions as to the highest amperage 5v to 3.3v regulator that would fit? we have to contend with pcb thickness of 0.6mm and whatever is left of the thickness of a motherboard standoff thickness.

Also gonna need to find room for some capacitors.

I was kinda thinkin the regulator could hang off the board though. just put some kapton tape down if the tab is live, if not then just glue it to the board.

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Reply 61 of 82, by Tiido

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The current capability means little when you don't have a heatsink to dissipate all the excess heat from all those ampers going through the regulator. For what I think you want to achieve your only choice is some switch mode regulator. LM26xx and its relatives are fairly easy to get going with and can provide you all the amps without any significant heat.

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Reply 62 of 82, by Sphere478

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Tiido wrote on 2022-06-16, 06:38:

The current capability means little when you don't have a heatsink to dissipate all the excess heat from all those ampers going through the regulator. For what I think you want to achieve your only choice is some switch mode regulator. LM26xx and its relatives are fairly easy to get going with and can provide you all the amps without any significant heat.

the solution to heat is distributed loading! load it up with ten of those bad boy regulators! lmfao jk.

I was kinda figuring though that if each one had its own regulator and you linked them all together whatever you installed could draw from all of them and there wouldn't be an issue also, thermally bonding them to the motherboard as a heatsink is also a option.

like the sata controller, the network card and the sound card aren't gonna pull a whole lot and the shared output of all I imagine could drive a video card.

If the answer is a switching regulator, I think continuing using the psu atx 3.3v becomes the obvious fallback.

https://www.mouser.com/ProductDetail/Analog-D … %2FXfjFdA%3D%3D

https://www.mouser.com/ProductDetail/Analog-D … ZUEf7XPJg%3D%3D

7a not bad..

I'm looking at the datasheets of these and at least one of them is listed as a part for running a 486 dx4 on a 5v slot (I think they were using these on the overdrives and interposers) the interposers usually didn't have much more than a really dinky heatsink.

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Reply 63 of 82, by Sphere478

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Re: ATX to AT pico Adapter!

btw, these projects are kinda related.

this adapter is set up to extract 3.3v from the atx connector, make -5V and adapt to AT motherboards.

file.php?id=139692&mode=view

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Reply 64 of 82, by Hoping

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I went the other way, not modifying the motherboard and modifying the pci card in question. The reason, in my opinion the only pci cards that may need the 3.3v will surely be more modern than the motherboard in question.
If you haven't seen it you can see here what I did; Chinese Rage XL PCI mods, improved compatibility and looking for a good overclock.
I think it would also be interesting to evaluate modifying the pci card in question, based on the fact that the motherboard does not have the 3.3v pins connected to anything, you can inject the 3.3v in any or all of the 3.3v pins of the pci card to feed it by taking them from 5V with a regulator, or a step down as I did.
Of course, modifying the pci card, depending on how it is done, can cause problems with motherboards that do have 3.3v pci slots, but a small switch would easily solve it.
On the other hand, to modify the motherboard, I would use a DC-DC step down based on an LM 25xx or one of its Chinese clones as I did in my case. The step downs with fixed output of 3.3v based on a LM25xx are cheap and I think that with their 3A they have enough power for this case, I mention the 3A because at that power I think they do not need a heatsink which makes some models so small that even they could be behind the motherboard and not be visible.

Reply 65 of 82, by Sphere478

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🤔

Oh yeah. There are a few ways to go about this. I like that this way is hidden and doesn’t alter the card. Personally.

Interested, could you link one of these devices you think would fit behind the mobo?

Cheap, small, low heat. 3a 🤔 might work.

One card that I have that I need this for is my gigabyte iRam drive. And I really don’t wanna alter it.

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Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 66 of 82, by Hoping

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I don't have one to test, but I think a step down regulator based on an MP2307 https://www.mouser.com/datasheet/2/277/MP2307-2945654.pdf might fit behind the motherboard, again they are pretty cheap And also easy to find., You can always glue a small piece of metal to the regulator to cool it a bit.
I think they could be a solution.

https://www.ebay.com/itm/325231775038?hash=it … asAAOSwUMxaPIaR
https://www.ebay.com/itm/143954995309?hash=it … fgAAOSw8-VgMU5x
If you don't like the variable resistor, just replace it by a fixed one, I say it because I know that a lot of people don't like variable resistors on power supplies.

Edit, I've found something interesting about the I-Ram drive. https://www.anandtech.com/Show/Index/1742?cPa … =0&page=3&slug=

Reply 67 of 82, by Sphere478

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Noted this:

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Beta 3.141

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Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 68 of 82, by Sphere478

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close up

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I don't think it would hurt anything having it connected but decided to make it optional. Just because it's different. I kinda expect basically everyone will probably connect this.

Last edited by Sphere478 on 2022-06-16, 12:38. Edited 2 times in total.

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Reply 70 of 82, by Hoping

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Sphere478 wrote on 2022-06-16, 12:19:

close upNew Bitmap image.png

I don't think it would hurt anything having it connected but decided to make it optional. Just because it's different. I kinda expect basically everyone will probably connect this.

You have noticed that the I-Ram card uses the 3.3vsb pin to keep the data, it indicates it in the Anandtech article that I mentioned, so it seems important precisely in your case.
https://www.anandtech.com/Show/Index/1742?cPa … =0&page=3&slug=

Reply 71 of 82, by Hoping

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Hoping wrote on 2022-06-16, 13:20:
Sphere478 wrote on 2022-06-16, 12:19:

close upNew Bitmap image.png

I don't think it would hurt anything having it connected but decided to make it optional. Just because it's different. I kinda expect basically everyone will probably connect this.

You have noticed that the I-Ram card uses the 3.3vsb pin to keep the data, it indicates it in the Anandtech article that I mentioned, so it seems important precisely in your case.
https://www.anandtech.com/Show/Index/1742?cPa … =0&page=3&slug=

But if you are using a AT motherboard with a AT power supply there's no standby voltage of course, so it doesn't really matter.

Reply 72 of 82, by Sphere478

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Hoping wrote on 2022-06-16, 13:26:
Hoping wrote on 2022-06-16, 13:20:
Sphere478 wrote on 2022-06-16, 12:19:

close upNew Bitmap image.png

I don't think it would hurt anything having it connected but decided to make it optional. Just because it's different. I kinda expect basically everyone will probably connect this.

You have noticed that the I-Ram card uses the 3.3vsb pin to keep the data, it indicates it in the Anandtech article that I mentioned, so it seems important precisely in your case.
https://www.anandtech.com/Show/Index/1742?cPa … =0&page=3&slug=

But if you are using a AT motherboard with a AT power supply there's no standby voltage of course, so it doesn't really matter.

yeah, prob gonna connect those pads I assume.

so I did another thing...

file.php?id=139780&mode=view

Re: The coolest socket 7 motherboard that you’ve never heard of

freeway design adapter

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Reply 73 of 82, by Sphere478

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file.php?id=140381&mode=view

file.php?id=140380&mode=view

Re: Socket 5/7/SS7 (Voltage Interceptor) Tweaker. (Beta)

CalamityLime made this VRM module for these devices. It turned out really well. Huge thanks!!!

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Reply 74 of 82, by CalamityLime

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I also may run into modding 3.3v into a 5v only pci soon.

Though, part of me is inclined to make a hybrid solution to what's been mentioned here. Just have to think about it a bit and look into specs.

Hint: i may try to resurrect the 5v to 3v3 card adapter idea.

Edit: or not, i thought pci would have -5 exposed on it but nope. Hmmm, still who knows. A card could give regulators some room to breathe regardless

Be Happy, it's only going to get worse.

Reply 75 of 82, by Sphere478

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CalamityLime wrote on 2022-06-28, 03:50:
I also may run into modding 3.3v into a 5v only pci soon. […]
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I also may run into modding 3.3v into a 5v only pci soon.

Though, part of me is inclined to make a hybrid solution to what's been mentioned here. Just have to think about it a bit and look into specs.

Hint: i may try to resurrect the 5v to 3v3 card adapter idea.

Edit: or not, i thought pci would have -5 exposed on it but nope. Hmmm, still who knows. A card could give regulators some room to breathe regardless

Using a card to power other slots probably won’t work because the traces probably aren’t routed.

I think the nicest solution is to make a version of the freeway adapter that fits your board.

Tell me your hybrid idea, curious.

I have a few projects relating to this, freeway upgrade board, gigabyte I-Ram drive adapter and this thread.

Sphere's PCB projects.
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Sphere’s socket 5/7 cpu collection.
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SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
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Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 76 of 82, by CalamityLime

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Sphere478 wrote on 2022-06-28, 04:44:
CalamityLime wrote on 2022-06-28, 03:50:
I also may run into modding 3.3v into a 5v only pci soon. […]
Show full quote

I also may run into modding 3.3v into a 5v only pci soon.

Though, part of me is inclined to make a hybrid solution to what's been mentioned here. Just have to think about it a bit and look into specs.

Hint: i may try to resurrect the 5v to 3v3 card adapter idea.

Edit: or not, i thought pci would have -5 exposed on it but nope. Hmmm, still who knows. A card could give regulators some room to breathe regardless

Using a card to power other slots probably won’t work because the traces probably aren’t routed.

I think the nicest solution is to make a version of the freeway adapter that fits your board.

I read that they were not routed alright but that's okay.

Tl;Dr of what i had thought of
Build the 3v3 bus using things here,

Build a card to convert 5 or 12 v to 3.3v, injecting the 3.3 into the rest of the slots that way

And hopefully include -5 for those who need it but no -5 connection on pci.

At least in my situation, i have more free pci slots than space to leave things dangle around inside the case. But i could always just slurp up some 3.3 from the CPU io reg.

Be Happy, it's only going to get worse.

Reply 77 of 82, by Sphere478

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CalamityLime wrote on 2022-06-28, 04:50:
I read that they were not routed alright but that's okay. […]
Show full quote
Sphere478 wrote on 2022-06-28, 04:44:
CalamityLime wrote on 2022-06-28, 03:50:
I also may run into modding 3.3v into a 5v only pci soon. […]
Show full quote

I also may run into modding 3.3v into a 5v only pci soon.

Though, part of me is inclined to make a hybrid solution to what's been mentioned here. Just have to think about it a bit and look into specs.

Hint: i may try to resurrect the 5v to 3v3 card adapter idea.

Edit: or not, i thought pci would have -5 exposed on it but nope. Hmmm, still who knows. A card could give regulators some room to breathe regardless

Using a card to power other slots probably won’t work because the traces probably aren’t routed.

I think the nicest solution is to make a version of the freeway adapter that fits your board.

I read that they were not routed alright but that's okay.

Tl;Dr of what i had thought of
Build the 3v3 bus using things here,

Build a card to convert 5 or 12 v to 3.3v, injecting the 3.3 into the rest of the slots that way

And hopefully include -5 for those who need it but no -5 connection on pci.

At least in my situation, i have more free pci slots than space to leave things dangle around inside the case. But i could always just slurp up some 3.3 from the CPU io reg.

If you wanna make 3.3v from the pci slot, then it can be made on the back of the board without using a slot. The regulators speced for converting 5v to 3.3v for 486 chips seem like a good option. Depending on how much load the card is. But networking the adapters can share the load.

Anyway, that’s something I was wanting to do eventually. But feel free to take the reins. No worries.

The pcb for the gigabyte iRam is probably a good place to start for that. I have all the stuff routed to the far side. Gnd, 5v, 12v, 3.3v and the 5/3.3v all seperate.

Feel free to snag it and start hacking 😀

As for heat from those linear regualtors, If networked, I don’t think it will be a problem. Most of the cards that you would use on these systems anyway, I don’t believe use a whole lot of amperage on the 3.3v rail.

Sphere's PCB projects.
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Sphere’s socket 5/7 cpu collection.
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SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
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Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 78 of 82, by Sphere478

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Re: AGP to PCI adapters - any PCB designers here willing to make one?

Need to investigate pin for 66mhz

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Reply 79 of 82, by CalamityLime

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Hey there

I made a mistake with the VRM module pcb. I accidentally swapped the vout and trim pins.
I'll fix it when I get a chance.

-Lime

Be Happy, it's only going to get worse.