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SN75C189A: Information required to replace SN75189ANSR to SN75C189ANSR

Satoshi
Guru 19595 points
Part Number: SN75C189A

One customer is considering to replace SN75189ANSR (NRND) to SN75C189ANSR.

Some necessary information is not included in the data sheet of SN75C189ANSR, so please provide the following information.

・Package thermal impedance or Power rating for NS package

　(It seems that the information about the NS package is not completely reflected in the data sheet.)

・Regarding switching characteristics, it is not possible to simply compare SN75189ANSR and SN75C189ANSR because the test conditions are different.

　(Test circuit and CL)

　Is there any material that can be compared under the same conditions?

・Please let me know if there are any other points to be careful about when replacing SN75189ANSR with SN75C189ANSR.

Best regards,

Satoshi

  • 0
    TI__Guru 70312 points

    Satoshi-san,

    An engineer has been assigned to this thread and will respond by end of business 10/24/2023 CST.

    Regards,

    Eric Hackett

  • +1
    TI__Guru 59680 points
    Satoshi said:

    Package thermal impedance or Power rating for NS package

    　(It seems that the information about the NS package is not completely reflected in the data sheet.)

    For this, I can try to submit a ticket to our thermal team to see if they can give us values but from my quick observation, it looks like the NS package is a bit larger than the other packages we offer so the values will probably end up being better (lower) than the existing packages in the datasheet (probably 80C/W or less is my current guess). If you are okay with waiting about 2 weeks (time it takes for thermal team to run the thermal simulations, then I will submit the ticket for this). Please let me know if it's required.

    Satoshi said:
    Regarding switching characteristics, it is not possible to simply compare SN75189ANSR and SN75C189ANSR because the test conditions are different.

    This device is quite old, we don't have the design files for the device anymore. This makes it difficult for us to collect meaningful data quickly to recharacterize the part for different loading conditions. It looks like the datasheet itself calls out the prior device in the bullet points in the front page to be backwards compatible though.

    Satoshi said:
    　Is there any material that can be compared under the same conditions?

    I can try to work with our subject matter expert on this to see if there are any other potential devices we can use instead. Those may potentially have different loading conditions we can compare to. I'll try to get back on this by the end of the week. Sorry for the delay on this.

    -Bobby

  • 0 in reply to BOBBY
    Guru 19595 points

    Hi Bobby

    Thank you very much for kind support,

    I understood that your situation, I looking forward to your update.

    Best regards,

    Satoshi

  • 0 in reply to Satoshi
    TI__Guru 59680 points

    Hi Satoshi,

    I've put in a request for the thermal model. 

    Taking a look at the RS232 portfolio, it doesn't seem like we have many options for 4x receivers and only the SN75C189A comes in the NS package which is not up for life time buy. This means we don't have any other devices we can share with the same test conditions and same package.

    -Bobby

  • +1 in reply to BOBBY
    TI__Guru 59680 points

    Satoshi,

    The thermal team was able to complete the request early. 

    -Bobby

  • 0 in reply to BOBBY
    Guru 19595 points

    Hi Bobby

    Thank you very much for your kind support.

    I understood thermal information.

    Best regards,

    Satoshi