Part Number: AFE4490
Dear TI's Experts，
During the use of AFE4490, we considered a single fault, such as the short circuit of INN and INP on the external lead wire, when the module needed to detect the fault according to the regulatory requirements.The chip has fault detection enablement, but each enablement interrupts the normal data acquisition.Therefore, we analyze the original data first. If there is any abnormality in the original data, we can conduct a fault detection within the chip.Now we have analyzed the original AD values of the six modules when INN and INP are shorted, which are respectively 0.4v, 0.4v, 0.4v,0V, -0.3v and -0.3v. The performance of the six modules is different (fixed 100K resistance, unbiased DAC, no gain.).Theoretically, INN and INP are short-circuited, so the value of differential ADC should be about 0V.Moreover, we also tested the AD values of the six modules without probe connection, which were all around 0v.
Now I would like to ask whether the above deviation is normal in the case of short circuit between INN and INP of the six modules.In addition, we also tested the demo board card, which is -0.8v under 100k configuration.