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SN65HVD96EVM: RS485 SN65HVD96 TINA SPICE model for simulation

Prodigy 30 points

Replies: 5

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Part Number: SN65HVD96EVM

Hello everyone, 

I am working on SN68HVD96 EVM in order to send power over Data Through RS485.

I have a question about the bellow figure mentioned in the datasheet (http://www.ti.com/lit/an/slla336/slla336.pdf). After the AC coupling why the "Aout" signal goes up? How did we get 0 decoding?    

Figure 1

Another question, about the Schematic of figure , Where could i find the schematic files? I need the SN65HVD96 PSPICE model to do the simulation mentioned bellow?

 Figure 2 

Thank you in advance

Regards,

Oussayran

  • Genius 14265 points

    Oussayran,

    First of all, SN65HVD96 doesn't function like a normal RS-485 transceiver. The device detects transition vs. non-transition, no matter with the polarity of A/B. In some sense, the signaling is somehow similar to the CAN. In the TI design, after the AC coupling cap, the signal lost it's DC voltage information, therefore the receiver cannot correctly decode the data. TI generally provides IBIS model for the transceivers. Unfortunately this device doesn't come with any models.

    Regards,

    Hao

  • In reply to Hao L:

    Hao,

    Thank you for your response.

    So, to solve the decoding problem, we need to implement the Trilevel Transmitter ? 

    What is the recommended chip used to send the Power over Data? I already have 2 EVM of SN65HVD96. if we need to buy other EVM with different chip, we are open!

    Thank you in advance

    Regards,

    Oussayran

  • Genius 14265 points

    In reply to Mohamad OUSSAYRAN:

    Oussayran,

    Yes, you may need to generate the trilevel. In this design, the transmitter is made of two SN65HVD96. Actually there are some other options to implement the power over bus function. 

    One is TIDA-01171, which also uses SN65HVD96. But the scheme is to check the edges for recovering the data.

    http://www.ti.com/tool/tida-01171

    The other one uses the regular RS-485 transceivers. In this design, the signal needs to be DC balanced, like Manchester encoding.  

    http://www.ti.com/tool/tida-00527

    If you don't mind, you can share some details about your application, such as data rate, distance, etc.

    Regards,

    Hao 

  • In reply to Hao L:

    Hao,

    Thank you for these useful information.

    In fact, i want to combine the data and the power over 2 cables like as mentioned in the above figures.

    The intended application is to create a communication between 2 transceivers at 115Kbps over a long distance up to 1500m.

    Would you please recommand a chip (RS485 or similar ) which is suitable with this application?

    I am still investigating and looking more deeply of the links you sent it before.

    Thank you in advance,

    Mohamad  

  • Genius 14265 points

    In reply to Mohamad OUSSAYRAN:

    Mohamad,

    Can you send me an email hliu@ti.com offline? I'll share you some information.

    Regards,

    Hao