Part Number: LMH7220
Hello,
on some PCBs the following schematic is working. i have a high speed currten signal and converted it over a shunt resistor in to voltage domain. To transmit a logic high/low signal i use the LMH7220. Later the output is going to an optocoupler, where the output of the opto goes in to an 3.3V µC. Now i struggle why some LMH7220 are working and some not. What also was interseting: at (hand) soldering they seemed to be very senstive, the output was not rectangualar. After replacing some and carefully soldering the output was as supposed to be (rectangular). But now I replaced several of them on one PCB and no output is comming out, when measuring the in- and in+ the signals looking great. I even removed the opto, to check whether the opto is the guilty one, but no. Was it just a coinsidence that some are working, and the below schematic normally should not work? or most of the ICs are destroyed due to ESD? I hope not, (but i ordered new one) to verify it, also i ordered an socket, to evaluate them prior soldering.
Maybe some of you can give me a hint.
