Need help identifying a case code part: BYO 531 6V

[smoothVTer]

Greetings all chip sleuths!

I have exhausted my google-fu and every SMD code book I could find online with no luck.    I'm having a lot of trouble finding what part number I am dealing with here:



Appears to be a 2mm x 3mm DFN-8 package.
Case marking code   is  BY0  531   6V     ( can't tell if the "0"  in BY0  is a zero or a capital "O" character )
Pin 1 = +5.0V
Pin 8 = GND
Pin 7 -->  Pushbutton switch

Any hints/advice?   Anybody recognize the "BYO" portion of this case code?

[amyk]

PIC12F519. First Google result for 'package marking "BY0"'. Someone selling them on Taobao agrees. (Picture attached for future reference.)