m4a1x/tps5430

TPS5430 based DC-DC Buck Converter Module with parts from JLCPCB

tps5430's Issues

Capacitor voltage rating is not considered for 12V output

TAJB107K006RNJ
C16133
1.7Ω 100kHz 6.3V -55℃~+125℃ 100uF ±10% CASE-B_3528 Tantalum Capacitors ROHS

Your schematic considered to use 12V for output. But output capacitor does not consider to use it. Because It's 6.3V rating.
Also can you check maximum ESR for capcitor?

Fix 5V output level

After some testing it looks like the output level of the 5V rail is quite a bit too high (almost 7V sometimes). Recheck resistors in the feedback loop!

Add Testpads/points

Since this is the first run, it would be nice to be able to look at all/most of the intermediate voltages to see if something is off or oscillating at an unwanted frequency. Thus a few test points would be nice, maybe even test pins

Add input voltage range on silkscreen

Makes usage easier. Maybe also label the solder jumpers as output.

Change status LED

Current status LED has a forward drop voltage of ~2.8V, thus it won't turn on with V_out of 1.8V. A lower voltage drop would make it possible to work with lower input voltages.

Verify that the transistor circuit still works

Maybe remove the transistor circuit altogether and just use a resistor that results in an acceptable forward current through the diode for all output voltages, i.e. max. ~25mA, min ~1mA, for V_out of 1.8V to 12V

Review Reverse Polarity Protection

A user on reddit (/u/mechbuy) asked what the purpose of the 100nF capacitor is on the reverse polarity protection is. I saw that in the CM4IO Module and used it as well, assuming it's either slow start or inrush control. After simulating it (see docs folder), I figured that it should probably be a 4.7nF-10nF Capacitor between gate and ground instead, to switch off the mosfet fast enough if there's a sudden voltage change at the input. As seen here: https://electronics.stackexchange.com/questions/461898/reverse-polarity-protection-p-channel-mosfet

Slow start is not needed because of the slow start control of the TPS5430 and the capacitors in front of it.

The value of the resistor can probably be increased to ~100k as seen a lot on the internet to reduce power consumption (again, the old one was inspired by the CM4IO board).

Add V_out status LED

It would be nice to have a status LED at the output with a low current (thinking of ~2mA) that shows if the output is working. Since the regulator maintains a constant 1.221V in stead-state operation, this could be used to control the current through an LED as described here:
https://electronics.stackexchange.com/questions/87713/driving-a-led-from-a-wide-ranging-input-voltage
and
https://electronics.stackexchange.com/questions/293062/how-to-achieve-constant-current-for-led-when-voltage-is-variable-in-mcu

Add USB-C?

Usually, I have either my Laptop/Desktop around or one of those cheap barrel jack power supplies. To make this board even more versatile I could add a USB-C plug with a USB-PD chip that negotiates a voltage as high as possible. Unfortunately, this would probably mean I'd have to use an extended part.

Change Reverse Polarity MOSFET

Ordering at JLCPCB I noticed that there's a minimum quantity of 15 for the AO3401A. Incidentially I found an even "better" pMOSFET that's also a basic part: APM4953KC-TRG, that also switches as 4.5V (80mOhm R_gs) and has a even higher V_gs of +-25V

I believe simple switching them out would be sufficient to save a bit of money :)

Move connectors to other side

As the connectors are often soldered by hand at JLCPCB (check!), there'd probably be no difference in pricing if they were to be placed on the back side to make the PCB even smaller.

Rotation of screw terminal

JLCPCB (Susie) reached out, because of the rotation of the screw terminal. There might be a rotation issue in the position file that I should verify.

Replace through-hole screw terminal with an SMD variant

Brings down cost (as it doesn't need to be hand soldered)

Move solder jumpers to backside

Since it doesn't require any parts, I think moving just the solder jumpers (and any test points) to the back side would be a good idea to save some space and make the board even smaller.

Add +12V output option

Check if a smaller inductance would bring the price down

If so, redo the calculations for all voltages

Add bottom silkscreen

It looks like a bottom silkscreen is doable, which I could've thought of before.. It might help to add some additional comments/descriptions on the bottom, e.g. for connectors or the OSS logo/link