Battery-powered ATmega328 with 5V voltage regulator - 7805 alternative?

Using Arduino Microcontrollers
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I've prototyped a design using an Arduino. The next step is to convert it to run off an ATmega328, make it portable (i.e. battery powered), and eventually onto a PCB.

Some components (e.g. HC-SR04) require 5V (i.e. not 3.3V). I've done some quick calculations and I believe the minimum current is ~5mA (328 + LCD + some large resistors) and maximum is ~70mA (+ 2x HC-SR04 + LED).

Most "battery-powered ATmega328" threads and guides I've read mention the 7805, but I'm aware it's an old chip and requires at least 7V input for 5V output. This could work if using a 9V battery, but if I was to use AAs I'd need five of them - but I'd prefer AAs.

If I want to use AA batteries (ideally 2 or 3, so peaking at 3 or 4.5V), which (step-up) voltage regulators are recommended?

The ones I've come across so far are LTC3525, MT3608, and U1V10F5, but even looking at the datasheets, I can't understand why I'd pick one over the other, or even if they'd all work for my solution.

Any advice appreciated :slight_smile:

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There are some LDO voltage regulator available such as this that will operate down to 5.2V and provide 5V from a 6V (4xAA) source

https://www.mouser.com/datasheet/2/268/21373C-2581432.pdf

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For making the 5V use a switching regulator. With battery operation a switching regulator would transform less volts to heat. Take the 5V and feed into a LDO3.3V regulator

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Use an off the shelf module like Adafruit MiniBoost 5V @ 1A - TPS61023 : ID 4654 : $3.95 : Adafruit Industries, Unique & fun DIY electronics and kits or https://www.pololu.com/product/2564 or (if you have time and trust China) https://www.aliexpress.com/item/4000956360100.html, unless your design is REALLY cost-sensitive, or you especially enjoy working with SMT components and critical layout of switch mode power supplies.

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