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TMS320F280049C: F280049 chip level questions

Rayna Wang
Expert 3680 points
Part Number: TMS320F280049C

Hi Expert,

I'd like to confirm the below chip level questions with you. Hope could get your help. Thanks!

1. For the application, F280049 just have two type, Q is for automotive and S is for others. Is that right?

My customer is used for PV inverter, they'd like to know if using S level is OK, and what's the difference about these two types.

 

2. Just double checked, that if customer could put a capacitor between PGA1_OF and PGA1_GND pins to filter the signal?

I have searched the TRM, the content in Filtered Acquisition Window seems supporting for this function.

Thanks!

Best Regards

Rayna

  • 0
    TI__Guru* 77460 points

    Rayna,

    Customer can use S device for PV inverter; Q grade has extra qualification for automotive Q100 standard.  This is not needed outside the automobile.

    For the PGA filter you are correct on the use of a cap for filtering and why we brought out this pin on the device.  Please see section 14.9.2 in the TRM http://www.ti.com/lit/sprui33  

    Best,

    Matthew

  • 0 in reply to MatthewPate
    TI__Expert 3680 points

    Hi Matthew,

    I got it. Thanks for your clarification!

    Best Regards

    Rayna

  • 0 in reply to MatthewPate
    TI__Expert 3680 points

    Hi Matthew,

    There's another question about PGA module.

    As the gain of PGA is 3/6/12/24, however could the gain be "1" to let output voltage follow the input voltage by floating the PGA_GND?

    Or it could connect the PGA_GND & PGA_OF pins together to make the gain is 1:1, could it? 

    Thanks!

    Best Regards

    Rayna

  • 0 in reply to Rayna Wang
    TI__Guru 62975 points

    Rayna,

    No, the PGA does not support Gain=1. In order to compensate for this, the smaller packages use hard-wired signal muxing to provide an alternate path to non-PGA ADC channels.

    For example, if we look at the analog resource table from the datasheet, you can see that on the 64-pin device, pin 12 provides access to both PGA1_IN and C0. If Gain=1 is desired, use the C0 channel.

    -Tommy

  • 0 in reply to tlee
    TI__Expert 3680 points

    Hi Tommy,

    Customer requires for high impedance function, which ADC could not achieved.

    As your suggestion, PGA could not use for the application that should achieve 1:1 & high impedance, could it?

    Thanks!

    Best Regards

    Rayna

  • 0 in reply to Rayna Wang
    TI__Guru 62975 points

    Rayna,

    Correct, the PGA should not be used for Gain=1 applications.

    The ideal signal conditioning for the ADC is low-impedance and high-bandwidth. However, high-impedance is a relative term. Have you reviewed the ACQPS approximation equations from the F28004x TRM?

    We have also added a section in the F2806x TRM for ADC signal conditioning for low-bandwidth signals. The equations will apply to F28004x as well.

    -Tommy