TI devices typically have a code printed or etched on their top side that contains information about what device it is, when it was manufactured, and where it was manufactured. This code is referred to by a few names such as top marking, top side marking, package marking, part marking, or device marking. An example can be seen below:
There is a tool on ti.com called Part Marking Lookup that can be used to determine which TI device you have based on the marking or you can enter the TI part number and the tool will provide valid markings. The manufacturing information is reserved for internal use only. The device marking can also be found on the datasheet in the package option addendum. For example, the CD4051BPWRG4 shown above has a valid marking in accordance with the datasheet:
More information on the topic can be found in our TI training video: Troubleshooting Tips: TI Product Markings and Labels
Some topside markings indicate environmental information such as E4/G4. More information can be found on TI’s environmental logo product labeling page or on our FAQ: [FAQ] What does G3/G4/E4 suffix mean on TI analog switches & multiplexers
Many counterfeit devices have markings and labels that resemble those on authentic TI products, leading customers to believe that they are genuine. Counterfeit products are not manufactured, packaged, labelled, stored or shipped according to TI’s standards and pose considerable performance, safety and reliability risks. If you suspect that you have counterfeit parts, please create a new case with our Customer Support Center.