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Galvanic Isolators

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Replies: 26

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Hi TI team,

We are designing a new product where our product will be interfacing to Industrial machines.

RS485 and CAN are the current requirements

Hence We need to use RS485 transceiver with Isolator and CAN transceiver with Isolator,

So Please let us know whether TI has these parts or not.

Awaiting for your quick response.

Thanks

Manjunath (Hardware Design Engineer)

Crevavi Technologies pvt ltd

  • In reply to Manjunath G14:

    Manjunath,

    While the TPS76350 is the example LDO from the datasheet in the SN6505, you can use an LDO with higher current capability like the TLV1117. If you could power both your transceivers from just one SN6505/transformer/LDO combination then this could save you money, complexity, and board space. Otherwise, your block diagram looks good.

    Respectfully,

    Lucas

  • In reply to Lucas Schulte9:

    Lucas,

    In my design 5V is used only for CAN and RS485 ranscivers. So meanwhile I found below schematic.

    Where it uses "760390015" transformer for converting 3.3V to 5V, Please suggest?

  • In reply to Manjunath G14:

    So I can also use the above 475uH transformer ?

  • In reply to Manjunath G14:

    I mean to say, If I can use a 1:2 transformer instead of 1:1:1, I can remove 5V power supply.

    "760390015" transformer provides a current out 350mA SO I think this is sufficient for CAN and RS485 Transceivers?

  • In reply to Manjunath G14:

    and also Isolated GND pin of RS485 and CAN can be connected together right? since single supply is used for both the transceivers?

  • In reply to Manjunath G14:

    Manjunath,

    The ISO1042 still needs 5V on Vcc2. You can power the Vcc1 of both transceivers with 3.3V.  If all you are looking to do is isolate the bus side of your system from the rest of it then yes your transceivers can share the same GND2. 

    Respectfully,

    Lucas

  • In reply to Lucas Schulte9:

    Hi Lucas,

    We can not use TLV1117 LDO because its drop out voltage is 1.4max at 0.8V output voltage, The output from the ISN6505/transformer combination will be 5V right?

    Hence the drop out voltage should be very less?

    TPS76350QDBVRQ1 LDO has 300mV dropout voltage@ 150mA.

    Manjunath

  • In reply to Manjunath G14:

    with Low drop out and current with mini 300mA and 5V output, " TPS76850QPWPRQ1" this is the only part I got. but the cost is slightly expensive.

    Please check and confirm.

  • In reply to Manjunath G14:

    Kindly reply, im waiting for your response

  • In reply to Manjunath G14:

    Manjunath,

    If you use a transformer with a turns ratio high enough to achieve >6.4V then the TLV1117 should be ok. For example, the DA2304-AL transformer is one of the recommended transformers for 3.3V to 5V application in the SN6505 datasheet. This transformer has a turns ratio of 1:2.2

    2.2 * 3.3V = 7.26V

    This outputs an unregulated 7.26V that is well above the minimum 6.4V for the LDO I recommended. 

    Respectfully,

    Lucas

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