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TPS7B7702-Q1: Load Regulation and Line Regulation

Meng Liu
Intellectual 1765 points
Part Number: TPS7B7702-Q1
Other Parts Discussed in Thread: TPS7A8101, TPS7B7702

Hi Expert

For load regulation and line regulation:

test condition: VI = VO + 1.5 V to 40 V and VI ≥ 6 V, IO = 10mA, voltage variation on FB pin and result is 10mV 

                       IO = 1 mA to 200 mA, voltage variation on FB pin and result is 20mV

but in TPS7a8101:

 

test condition: VOUT(NOM) + 0.5 V ≤ VIN ≤ 6.5 V, VIN ≥ 2.2 V  IOUT = 100 mA, and result is 150 μV/V

                       100 mA ≤ IOUT ≤ 1 A and result is 2 μV/mA

Question: customer want to choose the device load regulation 1%(1mA~200mA) so I could like to calculate this value base on datasheet value. 

Could you please tell me how to calculate this value base on datasheet form.

  • 0
    TI__Genius 12365 points

    Hi Meng, 

    Line and Load regulation are measurements of how much variation there is on Vout when there is a change on the input voltage and when there is a change on the load. 

    Having said that, you are showing 2 different devices, is the customer interested in both devices? 

    Thank you beforehand. 

    Best, 

    Edgar Acosta

  • 0 in reply to Meng Liu
    TI__Intellectual 1765 points

    Hi Acosta

    Customers want to choose the LDO that load regulation <1% but our description of TPS7a8101 and TPS7B7702 doesn't direct though percentage. so I don't know how to convert this value to percentage because I'm not sure our device if satisfy customer <1% requirements.  

  • 0 in reply to Meng Liu
    TI__Genius 12365 points

    Hi Meng, 

    Thank you for the clarification. 

    Load and Line regulation are measurements of how much the output deviates under the given conditions. 

    In the case of line regulation this translates to how much does the output change when there is a change on the input once the device gets to a steady state. 

    Similarly in Load regulation, this reflects how much the output changes when there is a load on the output. 

    In the case of TPS7B77, it is showing that there is a 20mV on FB voltage deviation when the device goes from 1mA to 200mA. Therefore, this translates to ~1.6%. This is only for the load regulation. 

    In the case of TPS7A8101, when considering everything, Line, Load and accuracy, the device has a 3% overall accuracy. If we focus on the Load Regulation only, it is best to look at the plots: 

    The spec shows that Vout can variate 2 μV/mA, therefore with a load of 200mA, this translates to 0.398μV. 

    Overall we can observe that the deviation is less than 1% for the TPS7A8101 even from the plots. 

    Best, 

    Edgar Acosta

  • 0 in reply to Edgar Acosta1
    TI__Intellectual 1765 points

    Hi Acosta

    Thanks for your help.

    and I have one question:

    In the case of TPS7B77, it is showing that there is a 20mV on FB voltage deviation when the device goes from 1mA to 200mA. Therefore, this translates to ~1.6%. This is only for the load regulation.

    For TPS7B77: How to calculate ~1.6% ,20mV/12V? could you please share the detail for this?

  • +1 in reply to Meng Liu
    TI__Genius 12365 points

    Hi Meng, 

    I apologize for the delayed response. 

    When you say 20mV/12V, are do you refer that Vout is 12V? 

    Will the Load be the same? 

    As far as the 1.6% calculation, this is just how much of 1.233V the deviation is. So if it only changes 20mV, then this is just 

    ((1.253 - 1.233)/1.233)x 100%
    Best, 
    Edgar Acosta

  • 0 in reply to Edgar Acosta1
    TI__Intellectual 1765 points

    Hi Acosta

    I misunderstood. I want to know "((1.253 - 1.233)/1.233)x 100%" so I don't have any concern. thank you!

  • 0 in reply to Meng Liu
    TI__Genius 12365 points

    Hi Meng, 

    No worries. Glad we clarified. 

    Have a good one!

    Best, 

    Edgar Acosta