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FDC2212: analog part defect, i2c works

Part Number: FDC2212
Other Parts Discussed in Thread: LDC1612

Unfortunately the FDC2212 broke during our 6kV ESD-pistol tests, but only the analog part is defect, the chip is still addressable via I2C and all registers are readable.

At the moment I just see that the values in register 0x00 and 0x01 are fixed values (with or without WD/AW error), which could be a possible state (once) in our application at a specific time.

 

But my question is about register of address 0x19 (ERROR_CONFIG). There I see bit 9 and 8 are set, which leads me to ask you for the meaning of those two bits. In the datasheet I just see “reserved, should be 0x00”. Can you tell me the meaning of those reserved bits? I’m asking because due to your support site I see that the LDC1612 has the same(or similar?) interface and a datasheet with less mistakes than the FDC2212’s datasheet, but in it’s description is no information as well. What are these bits 8 and 9 for ? Could it lead us to this "Analog circuit defect" detection ?

 

The second question: is there another way to detect if the analog part of the FDC2212 is broken ?

  • Hello,

    The FDC2212 ESD is rated to operated only up to 2KV as mentioned in the datasheet as per section 8.2 in the electrical table. The 6KV is beyond the operating range of the part and likely has caused damaged. 

    As far as reserved bits go please follow the guidelines as per datasheet section 9.6.1

    Fields indicated with Reserved must be written only with indicated values. Improper device operation may occur otherwise. The R/W column indicates the Read-Write status of the corresponding field. A ‘R/W’ entry indicates read and write capability, a ‘R’ indicates read-only, and a ‘W’ indicates write-only.

  • Thanks for your reply.
    But the questions are still the same:
    1. Is it possible to detect a defect of the analog measurement part of the circuit when the communication and the i2c still is working ?
    2. These Reserved Bits are sometime 1 (even i need to write 0), could it be a hint for defect

  • Hello User,

    Apologize for the delayed response. If the part is subjected beyond datasheet we don't know the behavior and its effects. The part may have damaged but we just dont have information to provide you details on the part. My suggestion would be to get another part and perform the normal operation. 

    The reserved bits are typically not intended for application use case. I am unable to provide you answers on the operation and functionality of the reserved bits. 

  • it's not really satisfying, but i have to accept that there is no solution (or will / or knowledge) to solve the problem of detecting a defect part in the field.