Capacitive isolated power supply - use MAX253 instead of MAX256?

Question

Hi, 
 I'm looking into a capacitive isolated power supply that has low quiescent currents. To that end, I found the app note for the MAX256 version ( https://www.analog.com/en/design-notes/isolated-power-using-capacitors.html ). Can I construct a similar thing using the MAX253 which has a lower quiescent current? I see that it is NOT a push-pull driver, but does that matter if I pull up the output with low(ish) value resistors? 
 Thanks, 
 R

EZAutoReply · Accepted Answer

Hi R, 
 I reached out to the designer of this part for more information, and this is what he said: 
 
 MAX256 and MAX253 are two different parts, and must be used in different modes. MAX253 is open drain and must be used with center tapped transformer, and the MAX256 without it (simple primary). 
 
 The apps note copied here can be used ONLY with MAX256 since you need a push pull driver to build that sort of charge pump with external diodes. This part is not meant to build a charge pump, but this is how it is used in that specific article. 
 
 If you built a similar schematic with a MAX253, it would have poor efficiency. The MAX253 has only pull down and you probably want to have a pull up with resistor. If resistor is high enough to avoid current waste on supply, then this would not work in pump mode because the high side action would be limited by the high resistance. If you use a strong resistance to be able to actively drive the cap, this would dramatically dissipate when you pull down the node. The MAX253 is not recommended for this application.)

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Capacitive isolated power supply - use MAX253 instead of MAX256?