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ISO6760: Designing with ISO6760

Part Number: ISO6760
Other Parts Discussed in Thread: ISO6763

Hi Team,
I want to isolate the SPI signal from a Printed Circuit Broad while entering another Printed Circuit Broad.
So I choose the isolator ISO6760.
The SPI from the main board is a 1.8V signal and the slave is a 3.3V device.
SO I connected VCC1 to 1.8V and VCC2 to 3.3V.
1). I hope there is nothing wrong with supplying 2 different voltage rails at VCC1 and VCC2.
2). What is meant by the supply current DC signal and Supply current AC signal in the datasheet?.



3). What is the current drawn from the VCC1 rail, VCC2, and the input signal rails.

The exact part number is ISO6763FDWR.

  • Hi Shibin,

    Thanks for reaching out and for your interest in ISO6763.
    Please see my inputs below to your questions, thanks.

    1). I hope there is nothing wrong with supplying 2 different voltage rails at VCC1 and VCC2.

    Yes, this is perfectly fine. Please see below FAQ which equally applies to ISO6763.

    https://e2e.ti.com/support/isolation-group/isolation/f/isolation-forum/732656/faq-can-i-power-the-two-sides-of-a-digital-isolator-with-different-voltages

    2). What is meant by the supply current DC signal and Supply current AC signal in the datasheet?.

    DC (0Hz) signal at the input means a static LOW/HIGH at the input. The currents listed specify the current device would consume if the input were to be left LOW or HIGH.
    AC (>0Hz) signal at the input is a signal with a non-zero datarate. The table lists current consumed by device for datarate of 1Mbps, 10Mbps and 50Mbps.

    3). What is the current drawn from the VCC1 rail, VCC2, and the input signal rails.

    Current consumed by VCC1 is ICC1 and the one by VCC2 is ICC2. The table screenshot that you have provided from the datasheet lists both ICC1 and ICC2 currents for various test conditions.
    Since the inputs are standard logic CMOS inputs, the current consumed by them is going to be <±10µA and is referred as IIH and IIL as stated in Electrical Characteristics table in the datasheet. I am copying below the table for 5V. Thanks.


    Regards,
    Koteshwar Rao