AD8436 CAVG Capacitance Selection

Hi,

1) We would like to use Murata ceramic capacitor "GRM31CB31E106KA75L"

   (5V supply Leakage Current at 25℃ : 1uA) for the CAVG capacitance

   of AD8436 in the following condition.

   Is there any problem?

   Operating Temperature : -20~55℃

   Operating Voltage     : 4.75~5.25V

2) We understand to use low DC leakage current capacitance for the accuracy.

   Is there the recommended DC leakage current value?

Best regards,

Nikkee

  • Hi,

    There are an awful lot of capacitors out there and I have not tested all of the values and manufacturers .

    However I have tested a couple of the new hi-temperature types due to the unique characteristics of no piezo-electric properties. The majority of ceramic capacitors have adequate leakage characteristics for rms-dc converters, especially if their rated voltage is much higher than the actual operating voltage (i.e. the actual dc voltage across the capacitor, or about 1.2VDC). I looked up the GRM31CB31E106KA75L on the Murata website but I couldn't tell what type of material the capacitor uses.

    I have tried the Kemet X8L series and found it to be quite satisfactory. It comes in 10uF size as well. The Murata may be OK, but you could try the X8L parts and compare to the Murata. If the results are the same for the for your application parameters then use the Murata. For critical applications use the X8L, especially if you expect high temperatures.

    Is this for a commercial application or is it a research project?

    I hope this helps,

    js

  • Hi jstaley,

    Thank you very much for your reply.
    It is helpful for us.
    For reference, the datasheet of Murata "GRM31CB31E106KA75L" is attached.
    It is a commercial application for our customer.

    Best regards,

    nikkee

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