SMD identification help

Hi All,

Any help on what this part is:

I have two identical boards, one that was from a previously opened device. And this device is missing on the one. So I am trying to find out what it is so I can get a replacement.

I see it as W3J and there are two dots, one under W and one under J.


Hello ByronT. I’m sorry, I was not able to identify your IC. Can you make out the logo? Here’s a listing of logos. I can try again if you’re able to make out the manufacturer’s logo. Sorry I couldn’t be more helpful for you!

Hi Jenny, I don’t believe there is a logo.


Hello ByronT - thanks for checking - sorry I couldn’t help!

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Hi @ByronT ,

Hard to tell. Seems to be on an automotive board. The NXP’s CAN chips nearby suggest that the chip dwells in digital domain. Could it be VHC1G126…?
cheers, heke


Hi Heke, if I was to take the chip off of the board would there be a way for me to test it to see what type of chip it is? Or is that too much of a risk of wrecking the working chip?

Hi @ByronT ,

Testing the plain chip is risky and may damage it. At least you’d need to know the supply pins and the rated supply voltage. It is advisable to attempt to get as much information as possible while the chip is seated to the target board. If you have a chance to power the board up, you could measure the voltages (or better waveform) at the chip pins to get some idea of the functions of each pin. The board seems to have a protective coating, which makes probing more difficult. The PCB appears to be designed “prevention of reverse-engineering” in mind, further hampering the “right to repair”.

Could guess that the pin #3 is ground, ruling out most of the LDOs. As there is only one capacitor nearby, this could be some near-DC operating linear chip or e.g. a one-gate logic such as the 1G126 mentioned earlier.

Also, check if the same chip is used in other locations on the same board. The components around the chip and visible PCB tracks may provide useful information.
Cheers, heke

Hi @heke,

Here are pictures of what I believe could be the same chip on the board. The only thing is that they say W37 so they may not be the same at all. It could be that W3 is the main numbering I guess.

W37 comes up as a Voltage regulator from TOKO. 3.7V

@Robert_Fay so probably not the same thing as the W3J then.

@Robert_Fay so I took those pictures off the board that was missing the chip. But I pulled the working board out and checked all the same chips on it. They all say W37 so I will assume that W37 and W3J are the same.

I will test the chips on the working unit and check against that datasheet you found and let you know.

So it looks like @Robert_Fay is right about which chip it probably is, but I am unable to find a cross or any in stock.

Anyone have a suggestion on that? I did see that there are some that are similar but would require a pin change of sorts to make it work.

Hi @ByronT , @Robert_Fay ,
Agree with Byron that the 3rd symbol is not relevant (is date, site or batch code).
The problem with the TOKO’s chips is that the pin #3 is “Noise bypass”. On PCB the pin #3 is grounded, which would suggest that the internal reference of the LDO is then shunted to ground. That should not be the case.
The “certain” information obtained from the layout is that pin #3 is ground and pin #5 is the supply. Pins #1, #2 and #4 are all active signal pins. The package seems to be SOT23-5 (0.95mm pitch).
Byron, if you have a multimeter with a continuity test (or resistance) function, could you test if the pin #4 of the devices shown in fig. smd3.jpg (pin #4 is the lower one on the right side of the package) is connected to any pin on the LM4550 codec chip seen on the right, respectively.
Cheers, heke

@heke Hi, I traced out the lines a ways. Neither pin #4 goes to that chip. 1 Pin #4 goes to the other side of the board to pin #10 on this chip:

@heke And the second pin #4 on the other chip goes to pin #4 on this chip:

As you can see that chip almost looks like it is double marked. But works and it isn’t the issue. Just info for where the pin #4 goes.

Hi @ByronT ,
The pin #4 of the chip (Microchip’s PIC MCU) in pic SMD6 is MCLR, i.e. chip reset input. The pin #10 for the chip in pic. SMD5 seems to be ground!! (the chip is probably CDP68HC68S1 by Intersil). Is there a chance that the pin #10 is for the PIC MCU and #4 is for the Intersil’s chip (i.e. flipped)? Anyway, I wonder, could you try to find where the tracks from pins #1, #2 and #4 from the missing 5-pin chip go?
Cheers, heke

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