Related to my last question, I decided to go with a step-down charge pump to convert 5V to 35V down to 3.3V at 10mA, due to the smaller required component size. However, I can't find a single charge pump IC rated to go up to 35V. Does anyone have any suggestions? If there are no ICs to do this, woudl there be any way of dropping 35V down to 18V with minimal loss and a small surface area?
I'd also be open to using a buck regulator, but it seems like a waste for only 10mA.