ADG5434 Power Supply

Hi,

I have following doubts regarding ADG5434. Could you clarify on those?.

1. Could you share the Maximum Pulse current which can be injected into the Dx/Sx pin over period of 100us? The datasheet provides value for the same over period of 1ms.

2. What is the Maximum pulse current that can be injected into the VDD pin? Our Sx/Dx pins can be subjected to Indirect Lightning transients, we have TVS diode (Clamps to 100V) and  1kohm current limiting resistances connected to each of the Sx pin. The current through each Sx pin would be 66mA (period - 100us) which would be drained into VDD pin via Internal clamping diodes. Since the same current is expected in all four Sx pins, the VDD pin would sink upto 264mA current over period of 100us. Can the IC survive this current? Also could the Internal Clamping diode survive 66mA current over 100us period? If the IC doesnt survive, what would be the max current via VDD pin and Internal clamping diodes over period of 100us?

3. In the "Absolute Maximum Rating" table, it is mentioned that the Analog Input pin can survive upto "VSS − 0.3 V to VDD + 0.3 V or 30 mA, whichever occurs first". Could you clarify this statement? Does it mean the Analog pin can exceed VDD+0.3V if the current is less than 30mA? Is this the clamping current through Internal Diodes?

Much appreciate your help.

Thanks & Regards,

Veerasamy

  • 0
    •  Analog Employees 
    on Jun 29, 2020 4:46 PM 9 months ago

    Hi Veerasamy,

    If lightning transients are a concern in your system I would suggest having a look at the below app note.

    https://www.analog.com/media/en/technical-documentation/application-notes/AN-1436.pdf

    This app note describes system IEC ESD testing did on the ADG5412F over voltage protection device. This involved using a current limiting resistor and TVS diode along side the ADG5412F and it shows what IEC ESD levels can be achieved using that solution. This would be a better solution that using the ADG5434 for protection against lightning transients.

    The ADG5434 has 8kV HBM ESD levels on all pins. There are internal diodes on the device so the current needs to be limited to 30mA to avoid damage to the diodes in an over voltage condition.

    Regards,

    Stephen