Author Topic: Test clips/grabbers for fine pitch ICs  (Read 3225 times)

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Offline ajb

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Test clips/grabbers for fine pitch ICs
« on: September 25, 2017, 02:40:52 am »
Are there good solutions for hooking onto the pins of an 0.65mm or smaller SSOP or QFP?  I have a set like this that are great for SOIC but almost impossible to grab onto anything smaller--or at least, you can't get them onto adjacent pins of anything smaller without shorting together or having them pop off at inconvenient times. 

The Pomona 72902 clips claim to work down to 0.2mm, which I find hard to believe, since it seems like even 0.5mm is going to be pushing the limits of material strength vs thickness for the leaves of the grabber and the body tube, so I'm a little hesitant to drop $15+ per clip without knowing if they'll work as advertised.  Anyone know if they do the business?  Or any other recommendations?
 

Offline Gyro

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Re: Test clips/grabbers for fine pitch ICs
« Reply #1 on: September 25, 2017, 04:33:47 am »
There is the style of probe that has a sprung contact on each side of an insulator (usually Kapton). When slid between two pins it provides contact to the pin on each side. They are used for high speed differential - HDMI or similar.

I can't think what they are called, or whether anyone other than the likes of Tek makes them.
« Last Edit: September 25, 2017, 04:38:45 am by Gyro »
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Online georgd

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Re: Test clips/grabbers for fine pitch ICs
« Reply #2 on: September 25, 2017, 04:40:38 am »
 
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Offline Jwalling

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Re: Test clips/grabbers for fine pitch ICs
« Reply #3 on: September 25, 2017, 05:32:27 am »
Perhaps these...
Google  Tektronix SMK4 or Agilent 10467-68701 or Pomona 6311
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Offline ajb

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Re: Test clips/grabbers for fine pitch ICs
« Reply #4 on: September 25, 2017, 06:09:10 am »
The called Wedge Probe Adapters:
http://www.keysight.com/en/pc-1455359/wedge-probe-adapters?cc=US&lc=eng

Those look neat, but quite spendy!  Especially since they're pitch- and pincount-specific, and you'd need one for each side of an IC you want to tap into.  I think I'd prefer to stick with individual grabber-style probes, since they'll be more versatile.

Perhaps these...
Google  Tektronix SMK4 or Agilent 10467-68701 or Pomona 6311
The Pomonoa 6311 have been superseded by the 72902 that I mentioned in the OP.  The others appear to be obsolete as well, and not widely available as used/NOS.  Anyway, I appreciate the suggestions, but my main question remains--I know there are probes that *claim* to work on 0.65mm ICs and smaller, but do they *actually* work reliably, especially when several are connected to adjacent pins?

I suppose worst case I can get a couple of the individual Pomona 72902 clips on my next Mouser order and see how they do before deciding where or not to buy the full $250 set.
« Last Edit: September 25, 2017, 06:13:30 am by ajb »
 

Offline tautech

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Re: Test clips/grabbers for fine pitch ICs
« Reply #5 on: September 25, 2017, 06:14:04 am »
The Mechano range was mentioned in a thread a little while back and I grabbed the link for future reference:
http://www.mechano.co.jp/pdle2.html
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Offline ajb

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Re: Test clips/grabbers for fine pitch ICs
« Reply #6 on: September 25, 2017, 06:25:43 am »
The Mechano range was mentioned in a thread a little while back and I grabbed the link for future reference:
http://www.mechano.co.jp/pdle2.html

Interesting, apparently their FP-5L are the Tektronix SMK4, and are or were sold by Chip Quik as well.  They at least show photos of a bunch of their clips side-by-side on a QFP, which is encouraging.  Now to figure out if they're actually available to buy and at what price...
 

Offline RayRay

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« Last Edit: September 25, 2017, 08:05:57 am by RayRay »
 

Offline ajb

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Re: Test clips/grabbers for fine pitch ICs
« Reply #8 on: September 25, 2017, 08:44:11 am »
You might wanna give these a go:
http://www.dx.com/p/plastic-multimeter-flat-test-hook-clip-grabbers-for-pcb-smd-ic-green-20-piece-134204

Those sometimes work on SOIC, but only if you get the good ones, and even then it's tough to get more than two or three on adjacent pins at the same time.  They're completely hopeless for anything finer pitch.
 

Offline alm

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Re: Test clips/grabbers for fine pitch ICs
« Reply #9 on: September 25, 2017, 08:45:19 am »
The question is about 0.65mm and smaller pitch, and one of the reviews from the cheap DX hooks is "Plastic tip is too thick for SOIC pins (cannot attach three 1.27mm pitch pins in a row, two are OK)". Does not seem like a suitable product for SSOP/QFP.

The Sigrok wiki has a decent overview including some pictures of the probes attached to ICs. In general the good ones will work down to the pitch they specify, but may have trouble if you are trying to probe more than a few adjacent pins at a time. Obviously the small ones are much more fragile than grabbers designed for SOIC or larger.
 

Offline RayRay

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Re: Test clips/grabbers for fine pitch ICs
« Reply #10 on: September 25, 2017, 09:00:42 am »
You might wanna give these a go:
http://www.dx.com/p/plastic-multimeter-flat-test-hook-clip-grabbers-for-pcb-smd-ic-green-20-piece-134204
Those sometimes work on SOIC, but only if you get the good ones, and even then it's tough to get more than two or three on adjacent pins at the same time.  They're completely hopeless for anything finer pitch.
Well, let me offer you an alternative solution then!
How bout you get a 30AWG wire spool, I.E this:
http://www.dx.com/p/7005-diy-pcb-copper-core-jumper-cable-wire-single-conductor-coil-blue-250m-183904
Cut up a small piece of wire for each pin you wanna test, solder it to it (using 0.3 or 0.5MM solder) and an SMD-compatible soldering tip, and then hook up an alligator clip to the other end of it for measurement. I think it'd work quite well.
 

Offline ajb

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Re: Test clips/grabbers for fine pitch ICs
« Reply #11 on: September 25, 2017, 09:12:33 am »
I've gone through enough Belden 8057 to know a thing or two about bodging wires onto ICs, thanks.  At the moment I'm looking for test clips so I don't have to do that every time I want to debug a board with a QFP or SSOP. 
 

Offline RayRay

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Re: Test clips/grabbers for fine pitch ICs
« Reply #12 on: September 25, 2017, 09:22:50 am »
Well, I guess you'll have to give those clips you've mentioned (Pomona 72902) a go then.
Clips for such fine-pitch IC's are hard to find. Just get a single clip for now and see how it goes.
And if it doesn't work as expected, at least you didn't shell out too much money for it!
 

Offline Assafl

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Re: Test clips/grabbers for fine pitch ICs
« Reply #13 on: September 25, 2017, 05:59:25 pm »
I was using the Machano clips today (on a SOIC so no big deal - just 4 simultaneous connections to hand hold while the scope was capturing). Not very impressive so I took a picture hooking it up to a random higher density device. Sorry for the poor quality of the pictures - hand held microscope...

The models I have in the picture are:
FP2S (the 4 green/yellow clips on the quad package)
FP7L (the 2 white clips on the motor driver package)
FP1B (only the tip is shown on the motor driver)

I try not to use the FP2S - they are very finicky. But for sub 0.5mm pitch, I don't have anything better.

The yellow rubber hose (called "position keeper") keeps them from slipping, especially at high pitch and "heavy" connecting wires. For really dense connections they come with a bar that keeps them aligned. Pain in the neck to connect though....
« Last Edit: September 25, 2017, 06:11:41 pm by Assafl »
 
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Offline Gabri74

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Offline ajb

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Re: Test clips/grabbers for fine pitch ICs
« Reply #15 on: September 25, 2017, 09:43:39 pm »
That's super helpful Assafl, thank you!  :-+  And for what it's worth, your pictures are better than most of the ones on the Mechano website!

Maybe E-Z Hook XKM?

http://catalog.e-z-hook.com/item/test-hooks/e-z-micro-hooks-single-hook-style/xkm-1
Those are the name-brand version of the clips in the DX link earlier, good for one or two pins on an SOIC, no good for anything finer pitch. 
 

Offline LaurentR

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Re: Test clips/grabbers for fine pitch ICs
« Reply #16 on: September 26, 2017, 03:23:14 am »
If you are probing around with an oscilloscope probe, I like the IC comb tips like this one from Cal Test:

http://www.caltestelectronics.com/ctitem/35-35mm-probe-accessories/CT3676
(for 0.65mm pitch)

Or the Tek equivalent (which seem to be cheap on EBay).

Of course, you need the probe. These exist for other types of probes.
 

Offline Dubbie

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Re: Test clips/grabbers for fine pitch ICs
« Reply #17 on: September 26, 2017, 05:48:35 am »
Because I am a bit agricultural sometimes, I just tack on a short stub of wire such as a through hole resistor lead trimming. Then I can use any clips  ;D

A touch with the iron and they come right off again. While not fancy, it is a secure method with no risk of shorting adjacent pins.
 

Offline _Wim_

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Re: Test clips/grabbers for fine pitch ICs
« Reply #18 on: September 26, 2017, 05:59:26 am »
The Pomona 72902 clips claim to work down to 0.2mm, which I find hard to believe, since it seems like even 0.5mm is going to be pushing the limits of material strength vs thickness for the leaves of the grabber and the body tube, so I'm a little hesitant to drop $15+ per clip without knowing if they'll work as advertised.  Anyone know if they do the business?  Or any other recommendations?

As a cheaper (but not cheap) alternative to the pomona's, you could buy this set: https://www.rapidonline.com/pjp-6800-8-smd-test-probe-set-17-2576

I have used them for a pitch of 0.4mm, but it really takes some fiddling. In my opinion the internal spring is not strong enough, so the grabbers are not always pulled back enough, creating sometimes bad contacts. But if you open and close a couple of times, normally you get them to grab firmly. In theory you should be able to do many pins next to each other, but luckily I never had to, because that will not be easy...
 

Offline RoGeorge

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Re: Test clips/grabbers for fine pitch ICs
« Reply #19 on: September 26, 2017, 06:04:16 am »
I'll go for wire-wrap or magnet-wire soldered from the chip pins to some 0.1 inch standard pins header.
The pin header is soldered somewhere on a ground plane for mechanical rigidity.

Then, can attach almost anything to the 0.1 inch headers, from the lousy Chinese logic probes to oscilloscope probes, ribbon JTAG connectors, or just simply solder wires on the male headers.

Offline bson

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Re: Test clips/grabbers for fine pitch ICs
« Reply #20 on: September 26, 2017, 08:13:45 am »
There are also IC cap tips (for SOIC or bigger, obviously not SSOP), like these from LeCroy (to fit LeCroy probes): https://store.teledynelecroy.com/collections/probe-parts-and-kits/products/pk007-008-ic-cap-0-05-pitch.  The little plastic horns make sure they only contact a single pin.  Obviously you need to hold the probe onto the pin; they won't clip or wedge in place.
« Last Edit: September 26, 2017, 08:15:31 am by bson »
 

Offline ajb

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Re: Test clips/grabbers for fine pitch ICs
« Reply #21 on: September 26, 2017, 12:31:41 pm »
As a cheaper (but not cheap) alternative to the pomona's, you could buy this set: https://www.rapidonline.com/pjp-6800-8-smd-test-probe-set-17-2576
  Those appear to be identical to the Pomona clips--are they both rebranding someone else's clips, or did one of them knock the other off?  Looks like I can get those for ~100USD, which is still a lot cheaper than the Pomona ones.  Anyway, I just ordered two of the Pomona clips in today's Mouser order, so we'll see how they do.
 

Offline LaurentR

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Re: Test clips/grabbers for fine pitch ICs
« Reply #22 on: September 26, 2017, 03:24:53 pm »
As a cheaper (but not cheap) alternative to the pomona's, you could buy this set: https://www.rapidonline.com/pjp-6800-8-smd-test-probe-set-17-2576
  Those appear to be identical to the Pomona clips--are they both rebranding someone else's clips, or did one of them knock the other off?  Looks like I can get those for ~100USD, which is still a lot cheaper than the Pomona ones.  Anyway, I just ordered two of the Pomona clips in today's Mouser order, so we'll see how they do.

Cal Test also has those in bundles of 6, 8 or 12 ($125, $160, $237 - before TEquipment discount).
http://www.caltestelectronics.com/ctitem/49-clips-surface-mount-device-smd-tweezers-a-test-clips/CT2848-6

These seem to be made by Electro PJP (also mentioned on the Sigrok page mentioned by alm above):
http://www.electro-pjp.com/fr/fichesearch?combine=6800

The rapidonline (UK) site has the set of 8 for $100 shipped to the US. The Reichelt (Germany) site is about the same price, but also has the set of 6 which comes down to about $85 shipped to the US - all a lot cheaper than Pomona and Cal Test.
« Last Edit: September 26, 2017, 03:45:29 pm by LaurentR »
 

Offline Gabri74

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Re: Test clips/grabbers for fine pitch ICs
« Reply #23 on: September 26, 2017, 08:32:31 pm »

Maybe E-Z Hook XKM?

http://catalog.e-z-hook.com/item/test-hooks/e-z-micro-hooks-single-hook-style/xkm-1
Those are the name-brand version of the clips in the DX link earlier, good for one or two pins on an SOIC, no good for anything finer pitch.

Nope, E-Z Hook are completely different from the cheap DX clips from Chinese vendors and are often suggested as best cheap-but-decent grabbers   ;D
http://catalog.e-z-hook.com/item/test-hooks/e-z-micro-hooks-single-hook-style/xkm-1

See also:
https://sigrok.org/wiki/Probe_comparison


 

Offline ajb

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Re: Test clips/grabbers for fine pitch ICs
« Reply #24 on: September 27, 2017, 12:41:32 am »
Nope, E-Z Hook are completely different from the cheap DX clips from Chinese vendors and are often suggested as best cheap-but-decent grabbers   ;D
Maybe we have different ideas of "completely different".  The basic geometry is the same, and it's the basic geometry that's the problem.  I have a whole pile of that sort of clip ranging in quality from terrible to very good, and none of them are suitable for smaller than 1.27mm SOIC.

I'm not opposed to spending decent money, I just don't want to wind up with even *more* clips for SOIC and still none for SSOP.  I should have the Pomona clips from Mouser tomorrow, if they look good then I'll probably order the set from Rapid.  If not, it'll be time to look for the Mechano.
 


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