• Resolved

ISO1540: ISO1540 Rise Time range

Part Number: ISO1540

Hi Sir,

Our customer want to use TI IOS1540 on product,

But we can't found out the I2C Rise time spec in the datashet,

Could you please share the Rise time range for me?


  • Hi Hugo,

    Glad to know that your customer is interested in ISO1540. Please note that ISO1540 has open collector/drain outputs because of which the output rise time will depend on the external components (pull-up resistor and any capacitance at output pin) and power supply voltage. For this reason output rise time specifications is not provided in ISO1540 datasheet.

    If VCC2 = 5V & Rpu = 1kΩ, assuming there are no external capacitance at output pin and since we know the input capacitance of the same pin is 7pF (CI) we can calculate the rise time to be as,

    tRise = 5 * Rtotal * Ctotal = 5 * Rpu * CI = ~35ns.

    Similarly, you can also calculate the rise time for different supply voltages, pull-up resistor & I/O capacitance values and also for VCC1 as well. Thanks.

    Koteshwar Rao
  • In reply to Koteshwar Rao:

    Hi Koteshwar ,

    Thanks for your response.