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SN6505A-Q1: SN6505A-Q1 Hardware review

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Replies: 6

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Part Number: SN6505A-Q1

Hello TI Team,

Please review the attached SN6505A circuit.

Design Contains 3.3V to 5V Isolated circuit and Ioslated CAN Transciever.

Please review both ASAP

Konnect-4G_Outjob.PDF

Thanks & Regards,

Manjunath

Hardware Design Engineer

  • Hi Manjunath,

    Thank you for posting to E2E!

    The SN6505A circuit of the schematic looks great; we will just recommend R65 be replaced with a 4.7kΩ resistor if possible and that in the PCB layout, C88 be placed within 2mm of the transformer's primary-side center tap. As a note, the LDO used here has a 150mA recommended current capability and there is a label near the output stating "5V/0.5A." If higher current is needed at the output, this LDO should be replaced.

    The ISO1042 sub-circuit also looks good as well. Termination values and decoupling are okay.


    Please let us know if you ave additional questions or follow-up comments.


    Have a great weekend!
    Manuel Chavez

  • In reply to Manuel Chavez:

    Hi Manuel,

    Thanks for the quick response and for the review comments.

    For the current Power isolated circuit, I used "750316032", AS per the spec of this transformer Which can take 3.3V and gives 5V at his secondary Side.

    Then same 5V is given to "TPS76350QDBVRQ1" LDO which is used for voltage stabilization which again takes 5V and gives right? The LDO has a 300mV dropout voltage here.

    So can you please explain on LDO is used here.

    Thanks

    Thanks & Regards,

    Manjunath

    Hardware Design Engineer

  • In reply to Manjunath G14:

    and also If you can suggest low cost LDO which gives 500mA it is greatful.

    Thanks & Regards,

    Manjunath

    Hardware Design Engineer

  • In reply to Manjunath G14:

    Hi Manjunath,

    You're welcome! 750316032 has a turns ratio of N = 1:2, which is high enough to transfer 3.3V across the isolation above 5V (~6.3V at 500mA,) specifically for use with LDOs on the output power supply. Without an LDO, the output power supply could vary widely as load current changes.

    The LDO in this schematic, TPS76350-Q1, is an acceptable LDO, and although we do not provide quotes for customers on E2E, our 1ku price on TI.com for uA78M05-Q1 is among the lowest for LDO's that meet operating specs in this schematic.

    Please let me know your thoughts and comments.


    Thank you,
    Manuel Chavez

  • In reply to Manuel Chavez:

    Hi Manuel,

    Understand.

    Please find attached updated schematic and review the same ASAP. 

    6116.Konnect-4G_Outjob.PDF

    Thanks & Regards,

    Manjunath

    Hardware Design Engineer

  • In reply to Manjunath G14:

    HI Manjunath,

    This schematic looks great! If the application is for automotive use cases, UA78M05QDCY (-Q1 automotive version) is available.

    Other than that, no changes are necessary.


    Respectfully,
    Manuel Chavez