BL3207 no marking

[ElectricDruid]

You'd have to rig up a proper test to know for sure. That means you need Vdd,Vbb, and Gnd supplies, and you need a biphase clock signal. And then you have to put something through it and see if it omes out of the other end!

If it's a blatant fake, nothing will happen. It's a dead chip that's been labelled as something valuable. If it's a poor fake, it might have started life as a QA failure from a production line of genuine 3207-alikes. And then it got relabelled as a more-valuable version of the chip. Sometimes different BBD lengths have been sold as other lengths, but that generally happens the other way around (1024-stage devices get sold as rarer 512-stage devices or 2048-stage devices).

Who knows? The only way you find out if it works is to test it thoroughly.

[matopotato]

Who knows? The only way you find out if it works is to test it thoroughly.

Thanks. I might have limited experience in that department.
Sounds like wait for Banzai support to answer. And try 5V just to see.
Assuming 5V "wrong pinout" will not kill it?

Before going circuit.

[ElectricDruid]

Assuming 5V "wrong pinout" will not kill it?

According to the datasheet, it should be ok.

[PRR]

That just looks likes a moulding mark, rather than a proper divot.

Yeahbut-- the vast majority of 'plastic' chips have "vents" to let the air/gasses out of the molding. Before fully cured, plugs are put in the vents to leave a more-or-less flush finish. Occasionally someone gets clever and writes the date/lot/cavity# on the plug so molding flaws can be traced-back.

There are other ways to vent a mold. But this seems nearly universal for semiconductors.

I do not know why the PDIP package doesn't have a universal orientation mark. A notch at the "top" is very common, and apparently used to orient automatic assembly, but is not universal.

Non-IC moldings, plastic parts for toys or appliances, may be vented out the end where they get broken-off the sprue leaving a ragged spot. {really? Firefocks spell-checker does not know "sprue"??}

[matopotato]

Banzai replied they were sorry and are sending me a new one. I asked about markings for pinout and the one they are sending should have a notch.
Fingers crossed. Stay tuned.

[duck_arse]

to paraphrase Mark Hammer, as no-one else is going to say it .... you are stranded on a dentless night.

regards testing at 5V but backwards, this is madness. if you put it in the socket backards, the supply is across not-supply pins, and it probably won't matter what voltage you put once the smoke clears. test it at proper supply, now that banzai are sending anew [a gnu?] with pin 1 determined from the print direction, see if anything works. is my opinion.


https://youtu.be/bnQyNMTUsck

[Mark Hammer]

What a great tune!  Thanks for that.  The guitar solo sounds like that one-woman-nuclear-power-plant Cordell Jackson.

[duck_arse]

interesting you say that. it is credited on the Tav Falco version to Cordell, Jackson, Bexley, but on the Allen Page disc it's credited to Cordell Miller. it was also covered by Lx Chilton, obvs.

[matopotato]

to paraphrase Mark Hammer, as no-one else is going to say it .... you are stranded on a dentless night.

regards testing at 5V but backwards, this is madness. if you put it in the socket backards, the supply is across not-supply pins, and it probably won't matter what voltage you put once the smoke clears. test it at proper supply, now that banzai are sending anew [a gnu?] with pin 1 determined from the print direction, see if anything works. is my opinion.


https://youtu.be/bnQyNMTUsck

So you are saying, testing with only 5V and not knowing the pinout, getting it wrong will fry it?
As opposed to

Assuming 5V "wrong pinout" will not kill it?

According to the datasheet, it should be ok.

?

[matopotato]

https://youtu.be/bnQyNMTUsck

Wow, that's how it sounds on 3V

[matopotato]

I set up a voltage divider for 9V battery to 5 and 4 V respectively. And also made the 5V into 1/15 and 14/15 of the voltage (this time 5V) to get 4.65-ish.
Then according to pinout and as I read the schematics:
0V to pin 1
5V to pin 4 (Vgg)
4.65 to pin 5 (Vdd)
Not sure what I was expecting. Did not put any signal to it.
Got 0V on the other pins.
This is with orientation according to "read text left to right, then pin 1 is down left corner"

Then I reversed it
Same voltages
This time I got 0 on pin 2 and 3
But on 6 and 7 I got some 4.5-ish and on pin 8 I got 2.65 ish.

Not sure if this says anything at all...
but at least some readings in the "wrong" orientation.

[Kevin Mitchell]

If it looks like a duck and quack like a duck...
I have not had good experiences with said vendor.

[duck_arse]

hey! what's with the duck cracks?


you are posed with a conundrum, matopotato. if you choose to test with pin 1 bottom left, and it's the wrong way around, the chip -- well, maybe doesn't destroy itself, let's say degrades performance. so, instead, test the IC in backwards ..... what do you proove? if it IS backwards, it is also now dead degraded. you only get to prove 'no, that way was the wrong way' if you don't get it right the first time.

I know bugger all about bbd chips, but if they are of cmos or mos internals, then any input pins will be needing to be tied high or low, otherwise odd things happen, and measures at outputs will be meaningless.

[matopotato]

hey! what's with the duck cracks?


you are posed with a conundrum, matopotato. if you choose to test with pin 1 bottom left, and it's the wrong way around, the chip -- well, maybe doesn't destroy itself, let's say degrades performance. so, instead, test the IC in backwards ..... what do you proove? if it IS backwards, it is also now dead degraded. you only get to prove 'no, that way was the wrong way' if you don't get it right the first time.

I know bugger all about bbd chips, but if they are of cmos or mos internals, then any input pins will be needing to be tied high or low, otherwise odd things happen, and measures at outputs will be meaningless.

Thanks,
I know bugger even less about BBD or IC in general. 
I went with what Tom the Electric Druid suggested after he had checked the datasheet.
So figured it would be safe and the switching would be possible.
How to interpret? I'm at the mercy of you all.
At least I do not think it fried.

I do have a 4889 or something still smoking from last year when my A/B-ing on the breadboard took a turn, along with the Op-Amp itself, for the worse.

[ElectricDruid]

I don't have a specific BL3207 datasheet, but the MN3207 says this:



The absolute max (above which the chip fries) for the supply pins is -0.3V to 11V. 0V to 5V is within those limits, so should be alright. I think...

I suppose the problem would be that the supply pins are pins 1 and pin 5, so if you reverse the chip, you have 5V on the Gnd pin, and 0V on the Vdd, which is then at -5V w.r.t to the Ground? So is that outside the limits? Now I'm not so sure! 

Anyway, it's pretty obvious which way up the writing should be and therefore which pin is pin 1.

[Mark Hammer]

I just sent a note to Banzai tech support, with a link to this thread, asking them to post a clarification here.  You'll note that the photo of the BL3207 chip on their website has no visible notch, so we'll assume the chips are fabricated this way, and the OP did not receive some sort of mutant BL3207.  The labelling on the chip photo is not visible, and Banzai does not show the notch on IC pics (which do have them) in any consistent orientation.  Sometimes they face "front" and sometimes they face "back".  Hopefully, they will respond soon and clear up this mess, because I just received my "ticket" (ticket ID 14101 and subject "Orientation of BL3207 chips")

[PRR]

you have 5V on the Gnd pin, and 0V on the Vdd, which is then at -5V w.r.t to the Ground? So is that outside the limits?

Yes.

They don't go into detail because.... what fool would do that?? (Holding my hand high, on a then-$100 8088 CPU socketed backward and smelling bad....)

If the rail pins are reversed, on most chips the substrate diode conducts near-infinite current. On small chips, this is instant death. (That big 8088 survived many seconds reverse voltage, go figure.)

[ElectricDruid]

Ok, so don't do that then! 

[matopotato]

Ok, so don't do that then! 

Well as posted earlier, too late...

[matopotato]

I just sent a note to Banzai tech support, with a link to this thread, asking them to post a clarification here.  You'll note that the photo of the BL3207 chip on their website has no visible notch, so we'll assume the chips are fabricated this way, and the OP did not receive some sort of mutant BL3207.  The labelling on the chip photo is not visible, and Banzai does not show the notch on IC pics (which do have them) in any consistent orientation.  Sometimes they face "front" and sometimes they face "back".  Hopefully, they will respond soon and clear up this mess, because I just received my "ticket" (ticket ID 14101 and subject "Orientation of BL3207 chips")

Ok, in my support case they say they are sending a new one, and promise it should have the notch.
I still have good experience from them as long as replacement comes through.