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Duo 22nd August 2003 04:56 AM

Possibly the smallest surface mount chip?
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Hey all. This is interesting; I ordered a chip from National Semiconductor. It's a LM4921ITL. It's about 2mm wide, 1.5mm long, and 0.5mm tall. It is a 16bit stereo I2C DAC with 32ohm headphone amplifiers, and digital volume control.

I ordered it because I like the simplicity of the I2C bus architecture and I would be interested in interfacing with audio.

I figured it was a standerd SOIC when I ordered it and didn't look at the datasheet. When it came I almost couldn't find the chips in the package (I ordered two.) I shook the tiny wee little flake of a package out of the static bag and admired it on the table. At first I thought it was a bit of plastic garbage that got into the package, but there were no chips. I looked closer at the little flake and found that it was a blister package with two chips in it.

I had to use tweezers and a razor blade to open it, even that was hard. I got one chip into my hand and glared at it, trying to count the almost microscopic pins. There are 20 of them, little bumps of metal on the bottom side of the chip. I could probably wedge the chip between two teeth to hide it. It is easily confused for a tiny shred of garbage plastic.

The question is, does anybody know anything about getting boards for these chips??? I know there are boards, but I'm not sure where to get them??

This pic shows the chip, between an 8088 processor, and a DIMM.
As you can see, the chip is barely twice the width of a "pin" on the 8088...

Variac 22nd August 2003 05:06 AM


Duo 22nd August 2003 06:52 AM

Small enough chip?

Would be a test of soldering skills to solder it in a circuit P2P. lol.

fr0st 22nd August 2003 08:47 AM

looks like a wafer to me..... don't they use them in the plastic packages??

Rudy 22nd August 2003 09:24 AM

its seems to be a Ball Grade Array ( BGA that is ) with a pitch off 0.5mm, sort off inpossible to place by hand, only with Pick and place machines these devices can be placed onto a PCB.

for the information, BGA's go *** tiny as a pitch off 0.3mm :bigeyes:

thats were the fun begin

To help you a little bit, i ones placed a BGA on a board simply by soldering the pads on te board, placing the chip, then add som glue to be sure the chip didnt move anymore, then burned the thing with a hairdryer from the bottemside from the pcb, this only worked for me 1 time out of 3, but that one time did it for me, good luck, you'l be needing it :(

Duo 27th August 2003 11:38 PM

Well, this was never supposed to happen, but I actually AM going to be soldering that chip in P2P:bigeyes:. It's going onto a piece of veroboard so that I can easily connect it into a circuit. I'm actually going to put two of these chips on one board so that I can run them simultaneously. Or, if I want, I can break the board into two independant chunks and use each one in a different project.

Can anyone tell me exactly how insane I am????

r0cket- 28th August 2003 12:39 AM


Originally posted by Duo
Can anyone tell me exactly how insane I am????
Probably not nearly as insane as you'll be by the time you're done trying to get that thing attached...

seangoesbonk 28th August 2003 12:44 AM


Originally posted by Rudy
its seems to be a Ball Grade Array ( BGA that is ) ...
Ball GRID Array.

Variac 28th August 2003 12:50 AM

How many pads do you need to connect?

Duo 28th August 2003 01:04 AM

I'm connecting every single one of them.

Just taking a 5min break. I have 7 more pins to solder and I'm done.

There's one pin that's being really fussy and won't bond.

Anyway, I'll post again when it's done...

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