Other Parts Discussed in Thread: ADS124S08
I am using TI ADC part# ADS131M04. Here is the ADC configuration used.
Clock Frequency= 2.048 MHz
Mode = VLP
Data rate = 1Ksps
OSR = 1024
Channel gain = 8 to 64 (depending on customer configuration)
Channel used = AIN1, AIN2, AIN3
DC block filter enabled : 0101b = 1/64
Data rate = 1Ksps
OSR = 1024
Channel gain = 1
Channel used = AIN0
DC block filter Disabled:
Channels AIN1, AIN2, AIN3 i'm using antialiasing filter with cutoff of ~820Hz (3rd order sallen key filter low pass filter)
Channel AN0 I'm using antialiasing filter with cutoff ~1.7KHz(passive RC 1st order low pass filter).
Now, the issue i'm facing is during ESD(Contact 6KV on enclosure), EFT(5Khz, 15ms burst) & FDOW(3MHz 50ms burst, 10MHz 15ms burst , 30MHZ 5ms burst).
EFT & FDOW is common mode noise , applied on external connector cables which has current transformer internal to PCB on AIN0 lines.
EFT, FDOW immunity test signal when applied on this ANI0 line is impacting normal signal measurement on AIN1, AIN2 & AIN3 during immunity tests.
similar observation is made while ESD contact discharge test.
Do i have to look into more insights of ADC IC to debug this issue ?
PS: I have isolated pre processing circuit (attenuation + filter) & shorted AIN1, AIN2, AIN3 during immunity test & ideally i'm reading 0V but when immunity test on AIN0 related channel is applied or ESD is applied i'm seeing 0V AIN1, AIN2, AIN3 is getting disturbed. This test was done just to make sure if pre processing circuit is causing trouble here but looks like pre processing circuit is stable & ADC IC is suspect ?
