I’m working on a portable system that uses a microcontroller and an analog/digital converter. I want use this ADC in dual power supply mode so I need a ±2.5V .
In my previous project, the system was wire-powered by USB and made use of an isolated dual output DC/DC converter which provides a ±3.3V, so with two LDO positive and negative regulator I obtained the ±2.5V.
Now I want to transfer the project in a portable contest and I need to make some changes to reduce the system size. For this reason, I can’t use the previous DC/DC converter type yet cause they are too big for my intent.
I tried to find on the web distributors some IC that provide a dual ±2.5V power supply from a single positive source, but I found one or two solutions that don’t satisfy me at all. Furthermore, these IC use a charge pump that create on the output a very high ripple, but I think that if I use two LDO regulator with high PSRR the problem is in part solved.
So, my questions for you are:
Do you have any suggestion to obtain a dual power supply ±2.5V from a battery, with the noise as low as possible?
Do you know some good IC that made this?
Thanks in advance.