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ISOW7821: high power consumption on Vcc without load

Olrik Maier
Expert 4630 points
Part Number: ISOW7821

Hi,

my customer has build first prototypes with ISOW7821.

He connect Vcc to 5V and is using ceramic cap of 1uF very close (<2mm) to the ISOW7821 for decoupling.

Without load at the input the part consumes a current of 100 to 200mA. When disassembling the cap the input current becomes 0 but also no current then is available at the output.

What could be the problem ?

Many Thanks

Best wishes,

Olrik

  • 0
    TI__Mastermind 49495 points
    Hi Olrik,

    Could you please ask customer to add another 10µF capacitor at the input (VCC) and make sure there is at least 10µF of capacitor at the output (VISO)? The device is not expected to function normal with only 0.1µF of capacitance at input (VCC).
    Please note that it is also important to place these capacitors on the same layer as ISOW and within 2mm distance from supply pins. Thanks.


    Regards,
    Koteshwar Rao