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Initial accuracy in Load condition of REF3033

Saemyi Jeon
Intellectual 1110 points
Other Parts Discussed in Thread: REF3033, REF3030

Hi all,

I would like to know initial accuracy in Load condition and drop voltage when load current flow more than 25mA. 

Please refer to the following specification.

Input voltage: 3.1~3.2V  

load current: several mA

 Could you answer the question as soon as possible?

 

Thank you for warm support in advance.

  • 0
    TI__Genius 13935 points

    Hello Saemyi,

    I am moving this thread to the other linear forum.  That part is not a high speed amplifier.

    Regards,
    Loren

  • 0
    TI__Guru 60610 points

    Saemyi,

     Below please see my answers:

     Samsung SDC is considering REF3033 that will be used for reference voltage of MCU ADC block in OLED TV.

    They would like to know initial accuracy in Load condition and drop voltage when load current flow more than 25mA.

     

    The max/min initial accuracy for Iload=0 and VIN=5V is specified to be +/-0.2%, max line regulation is 375uV/V, and the maximum load regulation is 100uV/mA (up to 25mA) so one may use those specs to calculate the worst case Vref for Iload=25mA; the maximum dropout voltage for REF3030 (Vref=3.3V) under 25mA load is specified to be 500mV (see below condition column for load regulation) and thus the minimum input voltage, Vin=Vref+500mV=3.8V, resulting in the input voltage range of  3.8V<Vin<5.5V

    If the customer operates REF3033 using minimum Vin=3.8V, the line regulation effects may contribute to the maximum Vref error of (5V-3.8V)*375uV/V = 450uV while load regulation may result in Vref error of 25mA*100uV/mA=2500uV.  Since the min initial Vref for REF3033 is specified to be 3.294V, subtracting line and load regulation related errors will result in the minimum Vref=3.294-(450uV+2500uV)=~3.291V at 25C.

     

    The above Vref calculation is the worst case number based on the min/max line and load regulation specs (typical numbers are much better) but assuming a zero contact resistance between the Vref, GND pins and load – therefore, Kelvin contactors must be used to avoid creating additional load regulation related errors.