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somebody knows this chip?
somebody knows this chip?
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Old 20th September 2019, 01:40 PM   #1
obiwankenobi is offline obiwankenobi  Argentina
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Default somebody knows this chip?

Hello ! A friend brought this Goldmund 330 Clone amplifier with a blown channel, that fortunately I could fix.

Taking a look at the rest of the PCBs, the amplifier has digital inputs in a separate receiver and DAC board that contains a strange chip. This chip has an "A 6400 129" marking, SOIC-16 package but no pin 1 indication.

Using a multimeter in Ohms, there is no reading between one row of pins and the opposite. Hard to know about readings between adjacent pins because there are external chip resistors. I was thinking about some kind or resistor or diode array ...

I googled as much as I could, searched for images, ICs marking websites, but no luck.

Maybe somebody at this forum has seen or used this chip before and could tell me what kind of chip it is.

I uploaded pictures of the board and of the chip, taken with a microscope camera. There is a dot that could be some kind of blurred logo but it is not placed exactly over pin 1 .. it is shifted a couple of positions.

Any information will help.

Thanks
Attached Images
File Type: jpg A6400 chip 04 .jpg (616.2 KB, 174 views)
File Type: jpg A6400 chip 01 .jpg (292.4 KB, 172 views)
File Type: jpg A6400 chip 03 .jpg (1.01 MB, 169 views)
File Type: jpg A6400 chip 02.jpg (176.1 KB, 190 views)
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Old 20th September 2019, 02:49 PM   #2
FauxFrench is offline FauxFrench  France
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obiwankenobi, may the force, or at least the tax department, be with you!

It seems to be a Broadcom ACSL-6400: ACSL-6400-06TE Broadcom / Avago | Mouser United Kingdom

Quad optocoupler. You can download the datasheet from there.
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Old 20th September 2019, 03:53 PM   #3
davidsrsb is offline davidsrsb  Malaysia
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Available from RS, but is it blown, you expect no continuity across it.
The soldering is terrible
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Old 20th September 2019, 04:59 PM   #4
obiwankenobi is offline obiwankenobi  Argentina
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Thank you so much FauxFrench !!!!!
I could never figure it out.
Thank you all guys !
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Old 20th September 2019, 05:12 PM   #5
obiwankenobi is offline obiwankenobi  Argentina
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FYI, the board is very neat. But this chip in particular caught my attention because it seems that this is not the original component to fit the board.

If you take a look at the picture, 4 SMD 470R chip resistors placed vertically , are standing on one their sides, and a cable connecting one of its ends. The amplifier works fine in all its functions.

So this chips shows some kind of rework for a replacement, there are no traces of footprints for these extra resistors.

Cheers !
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Old 21st September 2019, 04:14 PM   #6
davidsrsb is offline davidsrsb  Malaysia
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I suspect the board was designed for a digital isolator like this:
https://docs-apac.rs-online.com/webd...6b80e480ec.pdf
No series input resistor required
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Old 21st September 2019, 05:02 PM   #7
obiwankenobi is offline obiwankenobi  Argentina
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YESSS ! davidsrsb , very interesting point !

Why somebody would like to do such a mess in a nice PCB ?
One possible answer is pricing and/or availability.
Take a look at this:

ADuM3440 Stock and Price by Distributor

...versus

https://www.mouser.com/ProductDetail...0g%2FkIxEVM%3D

Maybe at a certain time it was more expensive or hard to source, so the alternative was to make this piece or artwork. The only reliable source is factory Analog Devices.

I will take a deeper look at this IC, seems to be pin for pin compatible, and then was for sure was the original for that board.

I wonder how they achieve this isolation technique ... what is this transformer really ?


Thank you.
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Old 21st September 2019, 07:22 PM   #8
obiwankenobi is offline obiwankenobi  Argentina
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I found it ! Just amazing !

https://www.analog.com/media/en/tech...s/isoPower.pdf

Enjoy !
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Old 23rd September 2019, 04:52 PM   #9
Mark Tillotson is offline Mark Tillotson
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Quote:
Originally Posted by obiwankenobi View Post
SOIC-16 package but no pin 1 indication.
Its got clear pin 1 indication, huge unmissable circle printed on the package, as well as chamfered edge on the pin1 side of the chip. The spot doesn't have to be precisely above the pin1, just on the right corner (remember many sizes and shapes of package exist, the same printing machine may handle SOIC8, SOIC4, SOIC16 etc etc).
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Old 23rd September 2019, 05:22 PM   #10
obiwankenobi is offline obiwankenobi  Argentina
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Quote:
Its got clear pin 1 indication, huge unmissable circle printed on the package, as well as chamfered edge on the pin1 side of the chip.
Thank you Mark Tillotson,

The dot you see is the blurred Broadcom corporate logo, that now comes clear in my microscope. You can consider it huge and unmissable, but this is not the pin one indication. Some brands, as Avago and Broadcom use the right reading position of the markings as an indication of pin 1, being this always southwest. Also, this is not the lead free indication neither.

The datasheet is clear about this particular:

ACSL-6400-00TE

Attached the corporate logo, and the package specification. The logo contains a tiny wave drawing that appears as a filled circle at first sight.

To my knowledge the pin 1 indication can't normally be 3 pins shifted away in serious manufacturers following standards, no matter the printing machine they use, LASER in this case that need tilted angle illumination to see it clearly.
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File Type: jpg Captura_001204.jpg (27.0 KB, 13 views)
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