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LMP8645HV orientation marking and documentation

Other Parts Discussed in Thread: LMP8645HV


In the photo of an LMP8645HV above, I'm not able to find a marking on the device that indicates orientation (pin 1).  How is this identified on the physical device and where is that documented in the datasheet?



  • Hi Jim,

    In either one of several ways:

     1. A dot, box or triangle in the pin-1 corner

     2. A slight bevel or long mark along the edge of the Pin 1 side

     3. The package text marking orientation (most popular since it is compatible with optical inspection)

     4. A thicker or thinner pin 1 (very rare)

    For #3 - Looking at the text horizontally as you would read it...Pin 1 would be in the lower left corner. This is the standard for almost all package markings.

    In the photo above, pin 1 would be in the upper-left (same orientation as the connection diagram on the datasheet). Also note that there is a white dot to the left of the package - this is probably the pin-1 marking

    Hmmm...You are right, the datasheets and drawings do not mention markings other than the "corner" marking - which is not as common now since all the space is needed for part numbers. I'll mention this to our packaging guy. My guess is that they are working under the understood assumption that all text has the same orientation.


  • Paul,

    Thanks for the response - can you provide some documentation that confirms how the text indicates the orientation?  Our customer is requesting this.

    Thanks again,



  • Hi Jim,

    I have pinged the packaging guy again to see if he knows of any "official" documents. I did not find anything in the packaging docs.

    However, I did find this page:

    The first row just happens to be the "DDC" package, which is what the 8645 uses.

    It shows the text orientation and pin 1's of all the packages. Note that the majority of the leaded packages (DIP, SOIC, TSSOP, etc) have Pin 1 in the lower left corner (reading text right-side up, left to right).


  • Paul,

    The customer is specifically challenging why the device does not have a dot on it.  Should it?  Is this possibly an indication they have a counterfeit device?

    Thanks again for your help,


  • Hi Jim,

    The pin 1 identifiers have been squeezed off the parts to make more room for the longer topmark ID's. The drawings have not kept up with the times.

    As more parts are released in SOT/SC-70 packages, the identifier codes have gotten longer (now up to 4 digits).

    There is just not enough room for readable text and a pin 1 dot. So other ways, such as the text orientation or horizontal stripe are used.

    I have not seen a "dot" on a SOT device in a long time....usually the text orientation is the only way. I feel your pain - I have had to test hundreds of devices in these packages - and it is hard not to occasionally put them in backwards...

    So I doubt if it is a counterfeit device.