ADS1110: ESD contact 6kV error

Hi Jin Hu,

Welcome to our e2e forum!  Can you provide a little more detail?  Perhaps a schematic of the area around the ADS1110?  Is the SDA of the ADS1110 stuck at this level after cycling power?

TEMP_SDA and TEMP_SCL connect to the MCU. MCU configure the two pins as open drain.

ESD:6kV shot on the metal part of the quipment enclosure，the metal connect directly to the GND using 18 AWG wire.

During and After the 6kV shot, the high level voltage of SDA is below than 1V. and the ADS1110 can not work properly.

when I reboot the equipment, ADS1110 can work properly again.

So what can I do to pass the ESD test.

Hi Jin,

What else shares the I2C bus?  From the scope capture showing SCL and SDA, it looks like the ADS1110 is actually working.  Obviously I don't know what VIN+ level you have, so I can't be sure if the conversion result is correct or not, but there are no signs of the part being in a latched state.  It looks like bus contention on SDA, so I suspect there is something else on the I2C bus trying to hold it low.  What side of R148 was the scope probe on in the first screen shot? 

Hi Tom:

I2C bus does not share with other devices. I found something new, just forget the high level of SDA. Now I find that if the high level of the SDA is correct(3.3V), the ads1110 conversion is also wrong. Here is some pictures:

First, I write 0x9C, after about 50ms，I read the data. the ADC conversion data is 0, but the configure register is 0x1C, which is correct.

I reset MCU, but it does not make any change. During the reseting, the power of ADS1110 is on.

Hi Tom:

Today I replace FB10 by 0R resistor, and ADS1110 works well. I don't have electrostatic discharge gun, So I use gas-fired igniter replace.

Later I will go to the Lab to do the ESD test.

Great!  Do let us know how you make out.

OK, No problem