I am working on an Electronics design which incorporates DC-DC buck converter voltage regulators. This is the first time I've been working with buck converters, so I have no experience and only limited knowledge on their operation. I've already found a design using the SY8113 for the same purpose as what I'm designing (power for a RPi CM3), but when I use the formulas in the Datasheet, the Inductor value I get does not match the "reference" design I've used.
To explain a little bit further; The RPi CM3 pulls a max load of 250mA on the 3.3V (and 1.8V) supplies, which in turn are supplied by the SY8113 circuits. These supplies also power some peripherals, but the total current should not go beyond 500mA. However, using the Inductor value from the reference design (2.2uH), it seems the power supply circuit is designed for a 3A power draw.
So my first question is: What is the consequence of designing such a power supply circuit for 3A, and then only pulling 250 - 500 mA from it?
Secondly, if I calculate the Inductor value from the datasheet formula, I get a minimum inductor value of 11.22 uH (so 15 uH should be a usable value). However, finding a 15 uH inductor with a DCR below 50 mOhm (which is recommended in the datasheet) seems quite hard. So what is the consequence of picking a 15 uH inductor with a DCR of 98-115 mOhm for instance?
I would simply like to know if I should use the 2.2 uH inductor from the reference design, or if I should use the value I get from the datasheet formula. Also, I would like to know about any problems which could occurr from choosing an inductor with a slightly higer DCR than recommended.