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ISO7731: is power consumption relevant with VCC1 and VCC2 power supply?

Intellectual 910 points

Replies: 1

Views: 51

Part Number: ISO7731


Customer found there is power consumption difference among:

A, VCC1=3.3V and VCC2=3.3V

B, VCC1=3.3V and VCC2=5V

485 Baud rate=9600.

they found the power consumption of supply solution A is lower than solution B.  did you see that and can you explain to me?

thank you!


  • Hi Yuan,

    The current consumption of device is expected to be higher for higher voltage and lower for voltage, though the difference is very minimal. I see that customer is observing the same and hence is not a problem. The primary reason for this difference is that higher voltage will enable marginally faster operation of device especially related to switching performance (like rise and fall times). The device achieves this by drawing marginally higher current and hence the difference.

    The above explanation is true considering all test conditions (like load capacitance CL) other than supply voltage to be the same. Any difference in any of the test conditions can also lead to higher differences in current consumption.

    I am assuming customer is seeing small difference in current and not an unusually big difference. Let me know if the current difference is large, thanks.

    Koteshwar Rao