Why can't MMA8451Q work? What's different between this two package?

[cheng-hanwu]

hi,

We have used MMA8451Q in our product for a long time.
But we met a problem in reading data from MMA8451Q which bought from digikey at 2017/12/15

It seems that the I2C address changed.

Then, we found out the package between new and old ic were different. 

What's the different between this two package?

Or was there any revision recently?

And what information can I get on this two package?

Thank for help !!!

[cheng-hanwu]

hi Jose,

Left side ICs caused the problem.

Our SA0 is set to low-logic, so the address uses 0x1C

So, there are no those ICs with part marking like that?

Thanks for help!!!

Regards,

CH

[reyes]

Hi CH,

I did a search in our system and I cannot find any ICs with the part marking like that.

I suggest you to check with your distributor for this devices, they should know what to do if the device they received (and sent you) are not the correct ones and should be able to replace them if needed.

Have a great day,
Jose

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[cheng-hanwu]

hi Jose,

Thanks a lot!!!

I will contact my distributor to solve this issue.

Regards,

CH

[reyes · Accepted solution]

Hi,

First, I would like to comment about the I2C Slave Address of the MMA8451. The MMA8451Q's standard slave address is a choice between the two sequential addresses 0011100 (0x1C) and 0011101 (0x1D).

The selection is made by the high- and low-logic level of the SA0 (pin 7) input respectively.

Now, one of the accelerometers shown in your picture does not seems to be correct, the correct part marking for this device should be as follows:

LINE1: 263

LINE2: 8451

LINE3: XXX

LINE4: *(Pin 1 indicator)

Can I ask which one is the one that is causing the problem and which is the I2C Slave address you are using?

Have a great day,
Jose

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