• TI Thinks Resolved

ISO7842: if short mode failure happens between 1st and 2nd side

Part Number: ISO7842


We would like to know if 1st and 2nd side short failure happens in ISO7842 internally.

In my understanding, ISO7842 has two cascade capacitor barrier has and they are connecting by bonding wire between them.

If a capacitor barrier broken, another barrier has basic isolation so rarely happen short mode failure between 1st and 2nd side.

Is my understanding correct?

Best regards,

Toshihiro Watanabe

  • Hi Toshihiro,

    Your understanding is correct.

    The device ISO7842 has two physically separate die inside device with one isolation capacitor on each die. These two capacitors are connected to each other by bond-wires. If VCC or I/O pin gets damaged due to some external over voltage then it is possible that the associated circuit in the die gets damage. Since one isolation cap is in the vicinity and in the same die, it is possible that the isolation cap also gets damaged.

    Since the second isolation cap is physically on a separate die, the damage on one die doesn't extend to the other isolation cap. Hence the undamaged isolation cap remains intact and still maintains basic isolation spec between Side1 and Side2. Thanks.

    Koteshwar Rao