I have low power (USB 5V, up to 500mA) available on a microcontroller board I am developing. Because the voltages I am going to measure (1.2-2.3V) using the MCU are not filling the ADC's range (0-3.3V), an opAmp seems suitable to scale it appropriately.
Case is, an opAmp needs not just a positive, but also a negative supply voltage to work properly. The opAmp I am looking at currently is the AD8027. So to provide its supply voltage this IC seems quite nice (judging by all its features, such as low-dropout-regulators): LM27762. But running TIs simulation web-software (Webench Power Designer), I am not getting the expected value of +3.3 and -3.3 Volt, when supplying it with the 3.3V of the microcontroller. It's more at a stable +3.1 and -2.9 Volt with attached load.
So my question is, how much will this degrade performance and quality? Will this still work to some degree? Are there better solutions to this kind of problem? Can I even trust the simulation?
Thanks in advance!