I have developed a board on which a LTM4677 switching regulator generates the supply voltage for an FPGA. With a header I can use the USB to PMBus adapter DC1613A to communicate with this IC.
The power-up sequence works and the FPGA works normally at first sight.
The problem is that you can't read correct data for output current and temperature on some of the manufactured boards. Either much too high or much too low temperatures are displayed in the LTPowerPlay, as well as negative currents. But not all boards have this problem.
Does anyone know what can cause this problem? The I2C seems to work normally and the IC is enumerated correctly.