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LMV324: EMIRR IN+ (dB) versus Frequency (Hz) information

Jonathan Geronga
Expert 7930 points
Part Number: LMV324
Other Parts Discussed in Thread: TLV4170, , , TINA-TI

Hi team,

Our customer would like to know the "EMIRR IN+ (dB) versus Frequency (Hz) information" that can be found on page 15 (Figure 25) of TLV4170 datasheet below:
http://www.ti.com/lit/ds/symlink/tlv4170.pdf

Is this information possible to share?

Please let me know if you need more information.

Thanks!

Jonathan

  • 0
    TI__Expert 6625 points

    Hi Jonathan, 

    As you can see, EMI is a special feature for TLVx170 which is why EMIRR vs Frequency is featured in the datasheet. I don't believe this data was collected for LMV324. Allow me to double-check with some device experts to see if this data is available to us. I will follow-up with you sometime tomorrow. 

    Regards,

    Bala Ravi

  • 0 in reply to Bala Ravi
    TI__Expert 6625 points

    Hi Jonathan, 

    I would recommend using the improved version LMV324A. It is a better part with lower offset and better EMIRR. 

    In LMV324A's datasheet, you can also find the plot for EMIRR vs Frequency. 

    Please let us know if you've any further questions. 

    Regards,

    Bala Ravi

  • 0 in reply to Bala Ravi
    Intellectual 290 points

    We will use the LMV324A moving forward.  Thank you for the advise. 

    We have a part from the past which is using the LMV324 and it failed our testing. We want to ensure that any part we replace it with will have a better EMI response but dont have the LMV324 chart for comparison.

  • 0 in reply to Chris Willis
    Guru 140200 points

    Hi Chris,

    the best cure against EMI is the consequent use of shielding, (external) filtering, decoupling and the use of a solid ground plane. Also keep in mind that the internal EMI filtering only works for frequencies above 10...100MHz. See figure 30 of datasheet of LMV324A.

    Kai

  • 0 in reply to kai klaas69
    Intellectual 290 points

    need 

    EMIRR IN+ (dB) versus Frequency (Hz)   CHART

    for LMV324, not LMV324A

  • 0 in reply to Chris Willis
    TI__Expert 6625 points

    Hi Chris, 

    I understand. EMIRR vs Frequency wasn't collected for LMV324 during production. Hence, we won't be able to provide this information now. Would it be possible for you to use LMV324A instead of LMV324. 

    Regards,

    Bala Ravi

  • 0 in reply to Bala Ravi
    Intellectual 290 points

    it would not since we know the LMV324 doesnt work we dont have any clue if LMV324A would work or not, we only know we need to be better than the LMV324

  • 0 in reply to Chris Willis
    TI__Expert 6625 points

    Hi Chris, 

    If you can share the schematic with us, we can run some simulations and let you know if this device will work for your application. 

    You can also do this on your own, by downloading our free TINA-TI software. The model for LMV324A can be found here: http://www.ti.com/product/LMV358A/toolssoftware. 

    I've compared LMV324 and LMV324A below, to help you understand the differences better:

    As you can see LMV324A is just an improved version of LMV324. This version is EMI hardened which may be useful to you. 

    Please let us know if you need any further assistance. 

    Regards,

    Bala Ravi

  • 0 in reply to Bala Ravi
    Intellectual 290 points

    EMIRR IN+ (dB) versus Frequency (Hz)  chart for LMV324

    Can you provide, YES or NO?

    TI Customer Support from a ticket I submitted keeps telling me to ask you.

  • 0 in reply to Chris Willis
    TI__Mastermind 25775 points

    Hello Chris,

    The short answer is No.

    The LMV324 was designed 20+ years ago without EMIRR in mind.  The LMV324A, which is a much improved version of the original LMV324, was designed recently with many improvements, including EMIRR filters.  It will have better EMIRR performance than the original device, but without any information about the circuit, PCB layout, etc. we cannot begin to predict how the performance will compare to the LMV324.  As Kai mentioned, there are many variables to consider when addressing EMI issues.