Error in readings of TMP05


I am using 4 TMP05 sensors with ADT7470 in daisy chain mode. We are currently testing it on our proto boards, where we found that in two boards, they are giving erraneous readings. In one board the values show large fluctuations in the reading and at times going to negative values. On debugging, we found that the first and last IC of the chain had gone bad. Because the O/P pin is giving a strobe signal without any output pulse. But even after replacing we found that the ICs are going bad repeatedly.

Can you please explain on what could be the issue?

On the second board, it is showing negative readings continuously. Here too, we found that the ICs have gone bad. These are newly mounted ICs.

I have attached the waveform of the O/P pin of the first device in the chain of both the cases. And the schematics too.