| Electronics > Projects, Designs, and Technical Stuff |
| Possibly wrong marking on a chip from Ali? |
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| Miti:
I bought 5 chips from Aliexpress that were supposed to be MC12080, a 1.1GHz prescaller, this is the link to Ali: https://www.aliexpress.com/item/4000301840060.html?spm=a2g0o.productlist.0.0.182362b3xmZHgC&algo_pvid=fe62791f-50cf-469e-bb2a-1c8a9f60d0a4&algo_expid=fe62791f-50cf-469e-bb2a-1c8a9f60d0a4-29&btsid=e57581f6-eb8f-48be-8922-383ef52909b8&ws_ab_test=searchweb0_0,searchweb201602_10,searchweb201603_55 and this is the link to the datasheet: https://www.nxp.com/docs/en/data-sheet/MC12080.pdf The chip functional table shows divide ratios of 10, 20, 40 and 80. The chips that I received seem to have the correct pinout, but they only divide by 2, 4 and 8. With SW1 - SW3 open, I get a ratio of 8, either SW1 or SW2 high the ratio is 4 and with both SW1 and SW2 high, the ratio is 2. SW3 does nothing. The chips have Freescale logo on them. I was expecting that the chips either work or they don't work, but to somewhat work? Or maybe that's why they are sold on Ali, otherwise they would be on Digikey? Can you think of any other chip that can follow the logic described before? I tried 2 of 5 and they work the same. Edit: One more clue that they may be different chip inside, the supply current at 5V is 7mA compared to 3.7mA typical in the datasheet. Edit1: Pin 7 that was supposed to be SW3 seems to be an active low shut down. Connected to GND, the output goes high and the supply current goes down to 4mA. Thanks in advance! |
| wraper:
Most likely MC12093 with fake marking. https://www.onsemi.com/pub/Collateral/MC12093-D.PDF |
| Miti:
Yes, that must be it, thanks! Why would they do that? Digikey price is the same for both chips. There's something wrong with the chips, other than the marking. SB current should be 50uA, in my case it is 4mA. Little big difference. I've already opened a refund request with Ali. |
| magic:
Maybe somebody cloned the /2~/8 divider but no one cloned the /20~/80 variant yet ;) |
| wraper:
--- Quote from: Miti on February 09, 2020, 08:48:12 pm ---There's something wrong with the chips, other than the marking. SB current should be 50uA, in my case it is 4mA. Little big difference. --- End quote --- Might be crappy clone of MC12093. Or you are measuring wrong. Try connecting input to GND and leaving output unconnected. |
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