Will a diode change how my IC works?
Yes, you'd have to allow for the 0.7 V drop but the voltage drop will vary with the current drawn.

Most of us would probably put the diode in the positive supply and keep battery negative as ground. This simplifies connecting up peripherals, etc., and is the normal way of doing things.







simulate this circuit &ndash; Schematic created using CircuitLab

Figure 1. (a) doesn't share ground with the battery negative as would be conventional. (b) does and has an inherent "neatness".