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TMS570LS3137: TMS570 GPIO optocoupler considerations

user5311130
Intellectual 400 points
Part Number: TMS570LS3137


Hello everyone,

I have several analog/digital inputs/outputs those must be isolated by opto-couplers(3.3V/12V other side). What could be the design considerations for gpio connections. Using series resistor is ok? What should be the series resistor value for interfacing 3.3V side of the optocoupler?

Thanks. 

  • 0
    TI__Guru**** 198766 points

    Hello,

    There is no special consideration for MCU side. If you use a MCU GPIO pin to control the optocoupler, when GIO outputs HIGH, the IRED turns on, and the light that the IRED emits then falls on the receiving phototransistor, resulting in current flow through the phototransistor’s collector and emitter.

    Please check the optocoupler's requirement from its datasheet, for example the LED forward voltage.