Hi all,
We have been experiencing issues with a design using SN65HVD72 RS485 transceivers. The R line is not behaving to the datasheet, so when the bus is idle it is going low instead of remaining high. This is creating phantom bytes on R when transmitting data as the chip we use toggles DE/RE between tx bytes.
Although we can work around this in software of course, it has highlighted that these might not be genuine TI parts as they are not behaving to datasheet. So we may encounter other performance/quality issues with them. Ideally although all of our suspicions from the marking and performance indicate they are not genuine, I am hoping someone will know if TI uses markings of this type.
I appreciate TI has a support team for anti-counterfeit but the page states that if I cannot provide all of the info they need, they will not look at the case. At the moment i do not have photos of device packaging or delivery slips. But I am aware our supplier may have obtained these from the grey market. I am hoping by providing photos this might be confirmable from the top markings alone.
Note this is the same issue reported here: https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1221609/sn65hvd75-r-output-issue?tisearch=e2e-sitesearch&keymatch=SN65HVD72#
We believe this to be a genuine TI chip from an older board and working to specification:
When we look at the potentially counterfeit ICs we see the markings are more deeply lasered. Also suspicious is the dimple for pin 1 as the etched markings spread into the dimple, and I would have thought if TI intended to use a pin 1 dimple they would change the etching design to avoid it.
We also found in our stock a board with another set of markings, which seems to be performing to spec this time. But suspicious as no TI logo, just TI in text. Is this something TI does?
Thank you in advance for your support, Mark
