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ISOW1432: ISOW1432

or nsl
Intellectual 280 points
Part Number: ISOW1432
Other Parts Discussed in Thread: SN74LVC1G17, , ISOW7721

Hello,

I would like to pass a PWM signal from an mcu that runs on 5v on one side to the other side that controls a driver (motor/led) ic pin (also 0v-5v-max via pwm signal). main issue is isolation between both sides.

Attached is the schematic as a suggestion option that uses 4n25 Phototransistor with SN74LVC1G17 buffer as i am not sure they fit together? (The question reffers to the Phototransistor left side circled in order to complete the isolation).

After looking on TI's ISOW1432 (that uses the same idea for other application) Can you please advice if TI has an 1 channel opto ic or any other solution ic to combine with the SN74LVC1G17 in order to pass this pwm signal smoothly?

Thank you in advance,


  • 0
    TI__Mastermind 49535 points

    Hi,

    Thank you for reaching out.

    TI isolation technology doesn't use optical method instead we use SiO2 based isolation that offers much higher performance. Most TI digital isolators have either TTL or CMOS logic input / outputs which are compatible with SN74LVC1G17 and can be interfaced without any issues. If you would like to use a digital isolator with integrated DC/DC converter then ISOW7721 would be the most suitable device.

    ISOW7721 is a integrated power digital isolator with 2 channels, you can use only one channel from the device for your application. ISOW1432 is an isolated RS-485 transceiver with integrated power and is suitable for RS-485 applications and won't be compatible with SN74LVC1G17.

    As suggested, you can go ahead and use ISOW7721 for your application. Let me know if you have any questions, thanks.


    Regards,
    Koteshwar Rao

  • 0 in reply to Koteshwar Rao
    Intellectual 280 points

    Hi Koteshwar,

    Thank you for your reply.

    Please advice where these ISOW7721 ic's can be purchased from? (its out of stock where i looked for includding ti). can i get samples from ti?

    In Addition, Just to make sure, is GND2 must shared both outputs A&B for the same common Grounds without gnd seperation(A/B)? if so, GND1&gndio the same?

    Can you offer similar functions ics as ISOW7721 (isolated -data & 5vpower) with seperated output GNDS for each output channel?

  • 0 in reply to or nsl
    TI__Mastermind 49535 points

    Hi,

    The samples can be purchased from TI website, TI authorized distributors and other online selling platforms like Digikey, Mouser and others. Due to high demand for semiconductor devices, many isolators are currently out of stock and they get sold very quickly even after replenishing the stock. This is also the case for ISOW7721.

    You can probably click on "notify me when available" option in the ordering section so that you get notified when they become available. Regarding free samples, I believe there is an option for request samples on the same ordering section. i.e., there are two options, one for requesting free samples (usually limited quantity) and the other for purchasing samples.

    ISOW7721 has two channels with one of them in forward direction and the other in reverse direction. Input of A and output of B are referenced to GNDIO while the input of B and output of A are referenced to GISOIN. GNDIO must be shorted to GND1 and GISOIN must be connected to GND2 either directly or through a ferrite bead as suggested in the datasheet.

    or nsl said:
    Can you offer similar functions ics as ISOW7721 (isolated -data & 5vpower) with seperated output GNDS for each output channel?

    We currently do not have digital isolators that are channel-to-channel isolated. Thanks.


    Regards,
    Koteshwar Rao