Flat "DIP IC" pins for PCB-based IC?

[visrealm]

Hi all,

I'm wondering if there is anywhere you can purchase DIP-IC-like pins for a PCB-based project which is designed to replace a retro IC?

I build these replacement RP2040-based TMS9918 VDPs:

...and currently I'm using turned pin headers which work fine, but would be great if you could buy flat IC pins instead.

I've searched to no avail. Any ideas?

Cheers
Troy

[Alex Eisenhut]

Yes, you absolutely can, that question pops up regularly, I have them on my desk, and every. single. time. I forget what they're called.

Except tonight, I guess.

http://www.dasarodesigns.com/product/batten-and-allen-ba3760-dill-leadframe-dip-pcb-edge-clip-pins/

(DIL, not dill, although that sounds delicious)

Just google "lead frame dil edge pins" and take it from there.

[PCB.Wiz]

...and currently I'm using turned pin headers which work fine, but would be great if you could buy flat IC pins instead.

For this problem in the past, we've used 'sacrificial' standard DIP sockets as 'converters' from headers to flat pins, that can go into standard IC sockets.
They also help protect the fragile turned pin headers.

[visrealm]

Thanks Alex and PCB.Wiz.

I found some similar at Digikey. It seems "Leadframe" is keyword.

I like the socket idea too, but it increases the stack height a bit which might be a problem for some.

[Alex Eisenhut]

Thanks Alex and PCB.Wiz.

I found some similar at Digikey. It seems "Leadframe" is keyword.

Careful, that's a SIL, like how SIPP memory modules were.

https://en.wikipedia.org/wiki/SIPP_memory

Might be useful if you're trying to make a Commodore 1541 hybrid module.

[visrealm]

Careful, that's a SIL, like how SIPP memory modules were.

https://en.wikipedia.org/wiki/SIPP_memory

Might be useful if you're trying to make a Commodore 1541 hybrid module.

Right you are. I could see it working, but it would be a bit... weird. Thanks.

[jonpaul]

Samtech

https://www.samtec.com/flex-stacking/

j

[ebastler]

Samtech
https://www.samtec.com/flex-stacking/

Those all seem to be big fat square pins which will widen/damage IC sockets when inserted?

[ebastler]

http://www.dasarodesigns.com/product/batten-and-allen-ba3760-dill-leadframe-dip-pcb-edge-clip-pins/

(DIL, not dill, although that sounds delicious)

Just google "lead frame dil edge pins" and take it from there.

Those pins which sit on the edge of the PCB are the "industrial" solution, I guess. But they won't allow you to sneak a trace or two inbetween the pins and the board edge -- neither on the top or bottom of the PCB. The design the OP shows does seem to use such traces in its routing. (On the other hand they should work nicely for multilayer PCBs, not blocking any real estate on the inner layers.)

There used to be a neat solution called "Flip Pins" -- individual flat pins stamped from sheet metal, held in plastic strips for easy assembly. I have used them in a few projects, but believe the guy who made them has discontinued this product. Not sure whether they are still available somewhere; this page has a description and a few links as starting points: http://oshchip.org/products/Flip-Pins_Product

[Alex Eisenhut]

Right you are. I could see it working, but it would be a bit... weird. Thanks.

Not at all, people don't realize SMT came before DIP packages... You can make these:

https://en.wikipedia.org/wiki/Flatpack_(electronics)#

BTW I don't really know what you're building but I commend you on taking the time to look into this solution. It's neater, and "correct", and obviously meant to work with DIP sockets. I see too many DIP-pluggable things with .100 header strips and it hurts my little nerd heart every time I see that.

The only annoying thing is, and it's a big one, is you need to trim these pins somehow. I don't think there are any ready-made DIP lead slicers out there that could fit on a kitchen counter either.

this page has a description and a few links as starting points: http://oshchip.org/products/Flip-Pins_Product

Very interesting.

[Benta]

I think these are what you're looking for:
https://www.te.com/en/plp/leadframes/Y30nn.html?n=42057&d=544927
They need to be cut after mounting.

[dorkshoei]

Yes, you absolutely can, that question pops up regularly, I have them on my desk, and every. single. time. I forget what they're called.

The issue with the the BA leadframes is the huge MOQ.   There doesn't seem to be a distributor who will sell off the reel.   This discussion on Parallax Forum has been posted here before and is informative.   The poster went on to design the "flip pins".

A standard IC leg protrudes about 4mm below the base of the device but the BA3760 (which fit a standard pcb thickness) are about 13.7mm so they need accurate hand trimming.   A pcb using them will probably also sit slightly higher in a socket than a true IC because the 2mm standoff of the leadframe extends below the pcb.

I think these are what you're looking for:
https://www.te.com/en/plp/leadframes/Y30nn.html?n=42057&d=544927
They need to be cut after mounting.

I don't think these are an option.   The only ones that supports a standard pc board thickness (1.57mm) are a horizontal attachment.    The Dual In Line only supports 0.63mm and 1mm pcb thicknesses.

AFAIK the BA3760 (there are several threads here on them if you search) is about the best option assuming you can find some at a decent price.   

[grantb5]

Flip pins:

https://shop.evilmadscientist.com/productsmenu/854

[amyk]

https://au.rs-online.com/web/c/connectors/ic-sockets-adapters/lead-frames/ ?

[salfter]

Comparing the dimensions in the provided image to what I could find on a datasheet, I think these are Batten & Allen BA3502 pins for a 1.0-mm PCB:

https://www.reactivemicro.com/product/lead-frame-pins/

Datasheet: https://www.batten-allen.com/hubfs/Downloads/DIL-F-Type-2021.pdf (go to page 2)

If I had to guess, the exact part number would be BA3502-TGBP-4A (or -1A...can't tell for sure). These might actually be available in small quantities (20, 40, or 100) at moderate prices instead of having to buy a whole reel of 50k pins.

"Flip pins" have been discontinued everywhere they were sold.  I found some pins from TE on DigiKey, but you're back to ginormous MOQs again: over 1M if you order through DigiKey (at a cost approaching $19K) or 33k for about $568 from a marketplace seller:

https://www.digikey.com/en/products/detail/te-connectivity-amp-connectors/1544169-1/2305328

[grantb5]

The turned/machined headers are OK, but I find the ones in the pico9918 photo to be too thick. Depending on the style, I would flip them and put the smaller diameter pin toward the receiving PCB/socket.  They take up a few mm of vertical height too which can be problematic.

These days I just use the flat pin headers that you see on the Arduino compatible hardware, though I source mine from Samtec at about $5 USD per 28 pin DIP. I can look for a part number. In my case I push them through the board I make then solder and clip off the plastic header. This emulates a DIP part pretty well, but it is a PITA to do.

[Kipling]

Late to the party here, but I have a solution, which mimics the unobtaniuum "flip pin" theme.

I bought a load of these from Digi-Key (also available from Mouser); they are available in any quantity.  https://www.digikey.co.uk/en/products/detail/te-connectivity-amp-connectors/1544210-2/4731536

Whilst they would work OK if you designed your board to be a smidge under 0.3" wide (or whatever width IC socket you intend to use as a receptacle) and you don't need to take any tracks between the through-hole mounting for the bent pin and the board edge, or if the through-holes would leave insufficient space for components in-between, then you can modify these pins so the centre-line of the pin is directly in line with the through hole and not the board edge.

For this, trim the straight pins (those that would normally be flush to the board edge) as far back as you can, then flatten out the bent pin.

The pins themselves are 0.5mm wide and 0.3mm thick and are reasonably soft. The through hole size I recommend is 0.65mm ID and pad size 1.65mm OD.

You can then solder them in and trim the pin length to suit.

Hope these photos explain what I've done.

[grantb5]

For my own case, I find those too thick and they bend too easy. I need something that will tolerate insertion and removal several times at minimum and won't ruin a standard dual wiping DIP socket. 4uConn makes the best part I've found so far and they are available in many places such as

36-pin Stacking header - pack of 5!
https://www.adafruit.com/product/3366

I make my PCB wide enough that these are soldered into through-holes on my board, then cut the tops off.