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Andy Waller

Andy is an Applications Engineer with Maxim Integrated Products.  He specializes in technical support for Maxim's product range for the entire life cycle of a product - from design to field..

 

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  • Hi Andy

    I have decided to use max1759 in my design. Now I'm looking for proper capacitors for it. In datasheet there is suggestion to use 10uF ceramic capacitors with ESR < 20mOhm. I have checked several capacitors I have got i office, with Frequency Response Analyser FRA1260 Solartron and the best capacitor I have found it was one with ~100 mOhm @1.5MHz. I have read a lot of Maxim documents, and I have found no sugestion what cap could be used. Could you help me with suggestion what manufacturer and what capacitor could I use in my design? or should I buy several different capacitors and check for their ESR?

     

    Regards

    Kamil

  • in reply to Former Member

    Hi Kamil,

     

    What output current and volatge ripple do you require? Indeed the lowest ESR caps possible are prefered due to improved effieciency, output impedance and low output ripple. In my opinion with the information I currently have on your requirements I'd go for the Oxicap NOJA106M006RWJNOJA106M006RWJ by AVX, Farnell order code 7565127RL. It has a capacitance of 10uF, ESR of 2mOhm max @ 100kHz and 6.3V rated volatge.

     

    Thanks

     

    Andy

  • in reply to Former Member

    Hi Andy

     

    Oxicap are very good caps, but there should be <20 mOhm ESR, while in NOJA106M006RWJNOJA106M006RWJ there is 2.2 Ohm ESR (not mili). Additionally @100kHz not @1.5 MHz. With frequency capacitor parameters much differ @1.5MHz than in 100kHz.

    Maybe my problem is that I have access to FRA. 

     

    Best regards

    Kamil

Reply Children
  • in reply to Former Member

    Hi Kamil,

     

    Correct, also the huge fluctuation with temperture and the fact specmanship comes into the equation it does make capacitor selection difficult, as I;ve never seen a 10uF 20mOhm@1.5MHz capacitor on the market. I have used Oxicaps before in SMPS with good performance. It looks like you 100mOhm cap maybe your best bet, what sort of output ripple can you tollerate?

     

    Thanks

     

    Andy