Are there 5V battery packs available without a boost converter?
Looking for a 5V portable power source without switching or conversion noise.


Use anything, for example a 7.2 V Lithum-Ion pack, and a linear (non-switchmode) voltage regulator, which drops the 2.2 V "overvoltage", and converts them to heat.

That's a waste of energy (and hence, battery life), but it doesn't incur switching noise. If you're drawing significant currents, you might need to cool your linear regulator.

However, the way you ask this question suggests you don't actually want that, but more something that is a low-noise switching power supply. Just because the supply you've been using so far has terribly switching noise doesn't mean you can't build a good switch-mode-based supply!

In fact, in many, if not most, applications, a switch-mode power supply with good output filtering is sufficient. If really necessary (e.g. sensitive analog high-bandwidth measurement electronics), design the SMPS to generate a voltage slightly above the target voltage, and regulate with a good, noise-rejecting low-dropout regulator ("LDO") to the target voltage. That's how professional radio equipment does it.