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enter image description here

I'm trying to identify this chip. The info I've been able to gather is the following:

  1. Packaging: it looks like WQFN (perhaps 20 pins???)
  2. Markings: 8524 C3H OEB22 (the 8 could be a B; the O could be a D; the first 2 could be a Z)
  3. The letters X and Y are printed on the PCB next to the chip

Thanks for the help.

I've added a picture. The lock is Schlage BE469

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  • \$\begingroup\$ why are you providing zero information about the lock? \$\endgroup\$
    – jsotola
    Apr 21, 2020 at 1:54

4 Answers 4

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The letters X and Y are printed on the PCB next to the chip

Considering the way that those letters are oriented, along with that style of IC package, then this IC is probably an accelerometer.

Looking at this cropped version of the original photo, I've marked the "Y" and (I think) the "X" which you mentioned:

cropped and annotated part of the original photo

The letter "X" is at the 3 o'clock position, indicating that the X-axis is in an east-west plane. Similarly, the letter "Y" is at the 12 o'clock position, indicating that the Y-axis is in a north-south plane. (The Z-axis would therefore be the plane "in and out of the screen".)

In an electronic lock, an accelerometer could be used to detect tampering e.g the lock being removed from the door (change of orientation, while the lock is set), or the shock from external attempts to force the door.

Update: I just looked on a product page for your Schlage BE469 lock, which refers to a "built-in alarm" feature. For example, the lock's user guide refers to a "Tamper" setting (page 8), which "Alarms when the lock is disturbed". A classic use for an accelerometer in modern consumer electronics is detecting the mechanical shock when someone attempts to tamper with a device, so that helps to confirm that the lock does likely contain an accelerometer.

Therefore I suggest to focus the search for an accelerometer as that IC, if you want to identify a specific device.

(On a side note, from the amount of apparent flux that's visible around it, someone might have tried to replace that IC already.)

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  • \$\begingroup\$ Thank you very much. Although I have not yet been able to 100% identify the IC, I believe you're correct in that it's an accelerometer w/ at least two axis, X and Y. \$\endgroup\$
    – kwboi
    May 7, 2020 at 1:15
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Its a LIS3DHTR 3-axis Accelerometer from STMicro

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  • \$\begingroup\$ Thanks for the feedback! I still don't know for sure what this IC is. From what I can tell, it's a QFN-16 (3x3x1) w/ a 4x3 pin configuration, which is not very common. NXP has several accelerometers in QFN-16 w/ the 4x3 configuration. However, tracing the connections on the board, the pin out for LIS3DHTR, which is an LLGA-16, is a better match than the NXPs. None of the ICs I've looked at have a package description that resembles 8524, though. \$\endgroup\$
    – kwboi
    May 7, 2020 at 1:23
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Could it be this one (Renesas Low Skew, 1-to-22 Differential-to-HSTL Fanout Buffer):
https://www.idt.com/eu/en/document/dst/8524-datasheet
This one actually has 64 pins, but you seem to be uncertain as to the actual number and 22 is not giving a whole number when divided by four.
You should have uploaded a photo of the whole board, so that we can see whatever detail is available on the chip.

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    \$\begingroup\$ That doesn't sound like the kind of component that would be used in a digital lock. A 1:22 buffer? \$\endgroup\$ Apr 21, 2020 at 12:06
  • \$\begingroup\$ Yeah, I figured so myself. I searched but couldn't find anything in such packaging with that model number. A photo should help, but the chip could have been remarked by the board maker. \$\endgroup\$ Apr 21, 2020 at 12:15
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There are a number of LM324 equivalents that include 8524 in the part number. For example NJM8524. Have a look at the pinout and surrounding components on the PCB to see if it looks like a quad op-amp.

If it's something really custom, you will find it difficult to get data on anyway, so I would take the approach it's likely to be a jellybean type component, so look at common devices i.e. opamps.

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