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ISO6721-Q1: Input Type & Current Consumption

Part Number: ISO6721-Q1

Hey Team,

I have a few questions regarding the ISO6721-Q1's use in a system where the measured voltage can change very slowly (millihertz range).

1. Is there any issue with holding the input between threshold states (For seconds or even minutes)? Does this result in higher current consumption of the device?

2. Is there a minimum dV/dt needed to avoid oscillations or other operating issues? From my understanding, the schmitt trigger with hysteresis will avoid any issue with minimum slew.

Best,
Dajon McGill

  • Hi Dajon,

    Thanks for reaching out. Please see below my inputs.

    1. Is there any issue with holding the input between threshold states (For seconds or even minutes)? Does this result in higher current consumption of the device?

    No, there shouldn't be any issue in holding the input pin at any voltage within recommended operating voltages. This shouldn't change the input current consumption and the input current should always stay <10µA.

    2. Is there a minimum dV/dt needed to avoid oscillations or other operating issues? From my understanding, the schmitt trigger with hysteresis will avoid any issue with minimum slew.

    Your understanding is correct, since the input is Schmitt triggered, there is no minimum dv/dt or minimum slew spec requirement for ISO6721-Q1 input pins. The device will be able to work without any issues.
    Please note that the actual value of VIT+(IN) can be anywhere upto 0.7*VCCI and VIT-(IN) can be anywhere after 0.3*VCCI and these values can differ from one device another but will always be within datasheet specs. Hence, the same slow input might yield the output with slightly different timings.
    Please also note that, a slow rising / falling input signal doesn't lead to a correspondingly slow rising / falling output. The output state change will be much faster and according to the spec provided in datasheet (tr / tf). Thanks.


    Regards,
    Koteshwar Rao