Query:

BillO · Post by **BillO** » Sat May 16, 2020 1:22 am

Is there such a thing as a through-hole SOJ socket?

GARTHWILSON · Post by **GARTHWILSON** » Sat May 16, 2020 2:03 am

I don't think I've seen such sockets, but there are adapters like you'll find at https://www.arieselec.com/products/over ... apters.htm . Here's an example. You solder the SOJ to this, and plug it into a DIP socket.

BigDumbDinosaur · Post by **BigDumbDinosaur** » Sat May 16, 2020 4:08 am

BillO wrote:

Is there such a thing as a through-hole SOJ socket?

at one time, I searched for such an animal and came up empty. I've never seen one.

Dr Jefyll · Post by **Dr Jefyll** » Sat May 16, 2020 4:09 am

Specifically, what chip do you wish to socket? Is SOJ the correct term to describe it? I'm looking at a Digikey search but SOJ isn't in the "Type" drop-down. Yet I'm sure I've seen sockets that match the same style which matches Garth's suggestion (assuming his suggestion is appropriate).

J.

BigDumbDinosaur · Post by **BigDumbDinosaur** » Sat May 16, 2020 4:23 am

Dr Jefyll wrote:

Specifically, what chip do you wish to socket? Is SOJ the correct term to describe it? I'm looking at a Digikey search but SOJ isn't in the "Type" drop-down. Yet I'm sure I've seen sockets that match the same style which matches Garth's suggestion (assuming his suggestion is appropriate).

J.

SOJ refers to a dual-inline package style with "gull wing" pins that wrap around underneath the package body. It's sort of like a a DIP package formed from opposite sides of a PLCC package.

: SOJ-32 Package

Here's an SOJ-36 soldered in place

: SOJ-36 Package

Dr Jefyll · Post by **Dr Jefyll** » Sat May 16, 2020 5:01 am

Thanks, yeah... I've seen chips like that -- and sockets to match, as noted. But I'm asking, is SOJ the correct term to describe it? I'm hoping the chip's datasheet will use vocabulary that matches some of DK's offerings.

GARTHWILSON · Post by **GARTHWILSON** » Sat May 16, 2020 5:32 am

Dr Jefyll wrote:

is SOJ the correct term to describe it? I'm hoping the chip's datasheet will use vocabulary that matches some of DK's offerings.

The data sheet for the ISSI memory I'm using now in my 4Mx8 SRAM modules (since Cypress doubled their price so I went to an alternate source) is at http://www.issi.com/WW/pdf/61-64C5128AL.pdf . The third-to-last bullet point in the left column of the front page says,

Quote:

Available in 36-pin SOJ (400-mil), 32-pin
sTSOP-I, 32-pin SOP, 44-pin TSOP-II and 32-pin
TSOP-II packages

Page 18 has the package drawing, and the title bar says, "36L 400mil SOJ Package Outline".

I've heard of J-leading DIPs in order to surface-mount them, but I have not seen a tool to do that. I would think it would work better than doing an I-lead or butt, where you cut the pin off right below the shank and use a good solder fillet to solder the pin to the pad. For that matter, I suppose you could just bend the pin inward just below the shank, like an L instead of rounded like a J.

BigDumbDinosaur · Post by **BigDumbDinosaur** » Sat May 16, 2020 12:24 pm

GARTHWILSON wrote:

Dr Jefyll wrote:

is SOJ the correct term to describe it? I'm hoping the chip's datasheet will use vocabulary that matches some of DK's offerings.

The data sheet for the ISSI memory I'm using now in my 4Mx8 SRAM modules (since Cypress doubled their price so I went to an alternate source) is at http://www.issi.com/WW/pdf/61-64C5128AL.pdf . The third-to-last bullet point in the left column of the front page says...

Funny, I was going to post that same data sheet last night, but sleepiness (an old man thing) caught up with me.

Dr Jefyll · Post by **Dr Jefyll** » Sat May 16, 2020 1:51 pm

Alright, I was able to find a specimen in my junk box. And, after some none too gentle coaxing with a heat gun, I got a look at the underside, too.

This style of socket is surface-mount, of course, but I suppose it could (with difficulty) be attached to the adapter Garth posted. The socket apparently has the same footprint as the naked chip.

I don't see anything that identifies the socket manufacturer, unfortunately. But they might also market a through-hole version. It would be the exact same product, except the little tabs would project rather than lying flat. No surprise, however, if Digikey doesn't carry either version.

I removed both samples from the board (a defunct PCI VGA card), and if they're of any use you're welcome to them, Bill. It'd be easy enough to slip them in the mail.

cheers
Jeff

BigDumbDinosaur · Post by **BigDumbDinosaur** » Sat May 16, 2020 3:52 pm

Dr Jefyll wrote:

I removed both samples from the board (a defunct PCI VGA card), and if they're of any use you're welcome to them, Bill. It'd be easy enough to slip them in the mail.

Bill has had bad luck with parts going through the mail. They have serious wanderlust and end up in places such as Poland and Switzerland.

BillO · Post by **BillO** » Sun May 17, 2020 12:13 pm

Thanks for all the info guys, and sorry for the late response. Been doing some upgrades to a short term rental property whilst in shut down mode.

So it looks like I'm a bit pout of luck on this. Maybe something like Garth's module would be a better approach.

Dr Jefyll wrote:

Specifically, what chip do you wish to socket?

I had been thinking about a 65C816 design and wanted to use 512KB memory chips. I had in mind the old Motorola MCM6946 (which I can still get NOS) or the CY7C1049CV33, but the ISSI chip Garth mentions would work too. They would be drop in replacements for each other.

Dr Jefyll wrote:

I removed both samples from the board (a defunct PCI VGA card), and if they're of any use you're welcome to them, Bill. It'd be easy enough to slip them in the mail.

Thanks for the offer Jeff, I really appreciate it but I'd have no way to solder those sockets on. Seems bit weird to put an SMD device in a SMD socket, but maybe not.

GARTHWILSON wrote:

I don't think I've seen such sockets, but there are adapters like you'll find at https://www.arieselec.com/products/over ... apters.htm . Here's an example. You solder the SOJ to this, and plug it into a DIP socket.

Thanks Garth. Unfortunately not available in the 36-pin variety.

BigDumbDinosaur wrote:

Bill has had bad luck with parts going through the mail. They have serious wanderlust and end up in places such as Poland and Switzerland.

True, this.

Dr Jefyll · Post by **Dr Jefyll** » Sun May 17, 2020 4:16 pm

I'll reiterate that whoever made my sockets very likely also offers a through-hole version. Seems it'd be a trivial variation, manufacturing-wise, involving nothing more than the omission or inclusion of a 90 degree bend.

What motivated you to want a socket in the first place? It's not difficult to solder a chip like that directly to an etched PCB. Were you hoping the socket would allow the RAM to later be reused in a different project? Or do you not plan on using an etched board?

In a protoboard context I found it easy enough to do a zig-zag pattern, thus adapting such chips to a .1" grid. (See some of the photos in this post. I also piggybacked the chips, but of course that's optional).

BillG · Post by **BillG** » Sun May 17, 2020 4:33 pm

Dr Jefyll wrote:

What motivated you to want a socket in the first place? It's not difficult to solder a chip like that directly to an etched PCB. Were you hoping the socket would allow the RAM to later be reused in a different project? Or do you not plan on using an etched board?

It may be an old habit from the days when chips were very expensive and we have low confidence in our soldering skills.

BillO · Post by **BillO** » Sun May 17, 2020 7:32 pm

In my case it's that I don't have confidence in my PCB design skills. About 60% of the time my first run has some error of some kind. I hate throwing away good parts with bad boards, so I try to minimize that as much as I can.

(I am getting better though - it used to be 100%)

GARTHWILSON · Post by **GARTHWILSON** » Sun May 17, 2020 8:18 pm

BillO wrote:

GARTHWILSON wrote:

I don't think I've seen such sockets, but there are adapters like you'll find at https://www.arieselec.com/products/over ... apters.htm . Here's an example. You solder the SOJ to this, and plug it into a DIP socket.

Thanks Garth. Unfortunately not available in the 36-pin variety.

I haven't checked availability recently; but if you can get a 40-pin, you can of course just leave 4 pins disconnected.

BillO wrote:

In my case it's that I don't have confidence in my PCB design skills. About 60% of the time my first run has some error of some kind. I hate throwing away good parts with bad boards, so I try to minimize that as much as I can.

(I am getting better though - it used to be 100%)

The checking method I used is in the first few paragraphs of my post at viewtopic.php?p=17653#p17653 . I do my schematics by hand since there are major things about all schematic-capture software packages that I don't like, and I do not get errors. The most complex board I ever laid out was this thru-hole one I laid out in the early 1990's. The board that was 3.8" x 4.8" with around 500 parts. It's mostly analog, with 30 ICs, and almost all the ICs have a lot of resistors and capacitors underneath them. It all worked on first try. No errors, with this checking method.

This, BTW, was done on a 16MHz '286 with 1MB (not GB) of RAM, and I never filled the RAM. It also had a 32MB (not GB) hard disc which never got more than about 20MB full, as I was using DOS 6.22.

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