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No-load quiescent current of ADP5304

Hello,

I have a question about the quiescent current of ADP5304.

The output is set to 1.8 volts and the input is 3.6 volts.

For the sake of meeting the spec about 180 nA with occasional switching, there were some common mistakes that I try to avoid.

1. There is no probe connected with input & output node 

2. Use DMM ( 34465A ) 's smooth filter function 

However the lowest quiescent current from my measure result is about 280 nA. ( The attachment shows my average result )

Is there something I should do to meet the spec ?

Thanks for sharing the information.

Ian.

  • Hi Ian,

    The typical quiescent current is 260nA rather 180nA. You can check the ADP5304 datasheet.

    BRs,

    Kevin

  • Hello Kevin,

    Thank you for sharing the information and hard work.

    But the Figure.13 shows the measure result is 180 nA from ADP5304 datasheet. 

    Which measure result I can follow ?  ( 260 nA or 180 nA )

    Thank you.

    BRs

    Ian

  • Hi Ian,

    Please use 260nA as this spec. the figure should be wrong. Sorry for the confusion.

    BRs,

    Kevin

  • Hello Kevin, 

    Thank you for clarifying this question.

    Could you provide the correct information for ADP5304-IQ at different VIN?

     

    Than how about the efficiency of ADP5304 ( Fig.5 ) ?

     

    It seems very similar to ADP5301’s results.

     

    BRs

    Ian Yang

  • Hi Ian,

    The Iq with VIN is as below. The efficiency would be only impacted a little under 1uA load current. Not sure what range of load current you care about.

    Vin Iq (nA)
    2.3
    246
    3.6 251
    4.2 258
    5 268
    6.5

    315

    BRs,

    Kevin

  • Hello Kevin,

    Thank you so much for your reply.

    Another question about the ADP5304 datasheet

        1. Input capacitor can be increased without any limit for better input voltage filtering. ( page 14/17 )

            Whether I could use a lot of 100 μF and stake them as a big capacitor ( such as 1000 μF ) to measure quiescent current?

            If the suggest is yes, then how to avoid the leakage current from big capacitor ?

        2. The range of load current I concerned were 1 μA to 500 μA, since our loading will be an ultra low power receiver.

            So far I have known were such voltage meter which used to measure VIN may cause extra current consumption

            ( VIN = 3.6 V,  ~360 nA flow into voltage meter )

            Could you suggest me some tips about how to accurately measure sub mA ‘s efficiency ?

    Thank you in advance.

  • Hi Ian,

    May I know what the real supply is in your real application? I can help confirm if ADP5304 is the best choice.

    You can use 100uF capacitor but you have to wait long time for a stable input current measurement. The ceramic capacitor should be very small that would not impact quiescent.

    You need set the meter to high impedance or else there is around 100nA current for Agilent 34410.

    BRs,

    Kevin

  • Hello Kevin,

    Thank you so much for your reply.

    In my application,

    I use VIN = 3.6V, VOUT = 1.8V and loading = 2uA, but the efficiency from my measure result were always about 68 %, which is not the same as datasheet shows, 78.5 % ( this were estimated value ).

    And my setup is

    1. VIN = 3.6 V from N6782A as a power supply
    2. IOUT = 2.0 uA from N6784A as a constant current load
    3. Measure VIN, IIN, IOUT & VOUT by using 34465A ( set the impedance as High – Z as your suggestion )
    4. IIN were averaged by 1000 samples 

    Do you have any suggestion?

    Thank you in advance.

    BRs

    Ian Yang

  • Hi Ian,

    If you use the ADP5304-EVALZ, there is a regulator diode D3 at PVIN so that may increase the input current. If you don't use the VINOK function, you can try ADP5300. The quiescent would be around 180nA.

    BRs,

    Kevin

  • Hello Kevin,

    Thank you so much for your reply.

    It was so sorry to bother you on your Saturday...

    Yes, I use the ADP5304-EVALZ to measure quiescent current and I setup my environment as below.

    1. Take off the regulator diode D3 but leave D1, D2, D4 & D5 

    2. set VIN = 3.6V without 4-wire sensing 

    3. wait for a long time ( about 25 min  )

    4. Average 40000 samples to calculate Iq  

    but the calculated Iq seems  have no obvious improved...

    Is there some set up issue lead to this result ? 

    Thank you in advance.  

    BRs 

    Ian