I want to power an op amp as 12V, but first I need to boost it to 15V. I want to power the op amp through my 5V pin Arduino pin. I eventually want to put this all on a chip.
You can switch that DC to DC converter on and off via an Arduino pin by using a mosfet. It will present a load of around 200mA. If you want a 12 volt output, there is a 12 volt version available. I guess you mean you will put all the components on a printed circuit board (not a chip)
Sounds interesting. Can you post a block diagram of what you are trying to do. You want to put this in a chip Putting what you are asking on a chip will cost a lot. If you can find somebody to do it, a foundry to make it and realize you will need to purchase a bunch of the chips as well. Search for "cost of a custom mixed signal IC" to get an idea. Mixed because it is analog, digital, and linear.