UICs (Unidentifiable Intergrated Circuits)

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UICs (Unidentifiable Intergrated Circuits)

Postby friedtransistor » 15 Mar 2013, 22:12

Anyone have the slightest clue what these two chips are? I've tried to figure out what they are, but nothing has come up so far...
IMG_1600[1].JPG

IMG_1601[1].JPG
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Re: UICs (Unidentifiable Intergrated Circuits)

Postby ppluis0 » 15 Mar 2013, 23:44

Hi friedtransistor,

The first image you posted belongs to an display driver. This is the link to their datasheet: http://www.datasheetarchive.com/9368PC-datasheet.html

The second chip maybe an LF442 but I'm not completely sure. If it's a dual operational the best test you can do is to plug in a breadboard, mount some diagram that employs a dual op amp (like a Tube Screamer, an OCD, a Marshall Guv'nor or the like) and test if work in that application.

In this case I recommend that you place a resistor of 100 ohms in series with the supply pin of this chip to avoid blow it up and damage your breadboard (yes, I have a couple of breadboards toasted... :lol: )

Cheers,
Jose
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Re: UICs (Unidentifiable Intergrated Circuits)

Postby friedtransistor » 18 Mar 2013, 02:02

Omg, thank you so much, this helps so much... I got these chips at a flea market/garage sale type thing. As to the second chip, I'll test it as an op amp again. I'm not sure if I have before or not... I'll see whether the lf442 is a single or dual.
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Re: UICs (Unidentifiable Intergrated Circuits)

Postby ppluis0 » 19 Mar 2013, 01:54

As said previously you can mount in a breadboard one of these 8 pins chips, mount the components for a TS or the like and see what happens.

It's important to put a resistor in series with the supply pin and measure if develops a voltage drop across it. This is to avoid flames and/or fumes during test and this way you can compare the current consumption of a know LF442 against this specimens.

Good luck !!!

Jose
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Re: UICs (Unidentifiable Intergrated Circuits)

Postby friedtransistor » 22 Mar 2013, 01:44

442 chip is a no-go. Either it isn't an opamp, or it's a dead opamp. And I had forgotten to put a resistor on the supply, but the chip remained cold. Oh well, thanks anyway for the info... :hug:
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Re: UICs (Unidentifiable Intergrated Circuits)

Postby karul » 22 Mar 2013, 15:59

Maybe it's a single op-amp

LF442 is dual
NTE 442-22 is single

442-22 NTE Equvilent NTE941M

http://www.weisd.com/test/GenericParts_ ... id1=442-22

http://www.weisd.com/store2/NTE941M.pdf
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Re: UICs (Unidentifiable Intergrated Circuits)

Postby friedtransistor » 23 Mar 2013, 22:46

wow, you are good. I'll give this a try. Btw, how did you know what numbers to search? I tried all the numbers on that stupid thing and couldn't come up with anything...
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Re: UICs (Unidentifiable Intergrated Circuits)

Postby karul » 24 Mar 2013, 00:59

friedtransistor wrote:wow, you are good. I'll give this a try. Btw, how did you know what numbers to search? I tried all the numbers on that stupid thing and couldn't come up with anything...


I wasn't 100% sure that it's an opamp, so I've searched for "ic 442-22", and one of the top links was:
http://www.weisd.com/test/GenericParts_ ... id1=442-22

Btw, the logo is "National Semiconductor".
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Re: UICs (Unidentifiable Intergrated Circuits)

Postby friedtransistor » 26 Mar 2013, 01:27

Thank you! It worked! I made this circuit to test the chip after reading the datasheet:
IMG_1694[2].JPG


It sounded great, and when I changed the feedback resistor to a 1m, it sounded like an overdriven amp. I tried an LM741 in the circuit, and it didn't sound as good. I like the 442-22 better than an LM386. Maybe even more than a JRC386. What is the difference between the two? I have an LM386 and JRC386, and the JRC seems to have a better sound and not overheat as much...
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Re: UICs (Unidentifiable Intergrated Circuits)

Postby karul » 27 Mar 2013, 19:48

I can't find much more info about 442-22 except that it's a NTE941 equivalent.
http://nte01.nteinc.com/nte%5CNTExRefSe ... enDocument

LM741 and NTE941 are general purpose operational amplifiers, LM386 is audio power amplifier.

NTE941 (442-22) and LM741C are equivalents and there is no difference between the them if you compare the datasheets.

Good for you if you're pleased with the sound of 442-22 - use it.
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Re: UICs (Unidentifiable Intergrated Circuits)

Postby friedtransistor » 28 Mar 2013, 23:26

Sorry, I meant between the lm386 and jrc386... :blackeye
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Re: UICs (Unidentifiable Intergrated Circuits)

Postby karul » 30 Mar 2013, 22:34

Well, LM386 and JRC/NJM386 have same pinout, so they are to some extent interchangeable. Their internal circuitries are not the same.

There are different versions of LM386:
LM386N-1
LM386N-3
LM386N-4

You can use LM386N-1 with 4-12V power supply (absolute maximum ratings 15V)
For LM386N-4 you can use 5-18V supply (absolute maximum ratings 22V)

JRC/NJM386 have operating voltage of 4-12V (absolute maximum ratings 15V)

Both have same voltage gains from 20 to 200, same THD 0.2%.

Also there is a LM /JRC 386B.
LM386B have operating voltage of 5-18V (absolute maximum ratings 22V), THD 0.1%

Datasheets:
http://www.ti.com/lit/ds/symlink/lm386.pdf
http://semicon.njr.co.jp/eng/PDF/NJM386_E.pdf
http://users.ece.utexas.edu/~valvano/Da ... LM386b.pdf

For a tonal differences and preferences you are the judge.
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