Part Number: SN75176A
Hello, We use the device in one of our products for RS-485 communications. In our last couple builds, we are seeing a very high fallout in our final testing. about 5%.
We had simply asked our contract manufacturer to replace the chip and we would sort it out later. Today I tested a bunch of boards pulled from final test, and the SN75176A devices are failing with a very odd bug, seems to be logic related. The devices transmit data just fine. But once we finish sending a byte of data and toggle the RE and DE pins low together to enable receive, about 70 microseconds later, the R pin on the SN75176A toggles high on its own without any change on the RS-485 bus. Once the RS-485 bus goes low, it seems to "reset" the buggy logic in the device and the rest of the changes in the bus are translated properly.
Is this a known issue? Is TI making steps to correct this?
Photo of example parts:
