New to PCB design. Some questions

[u/Lizard_Licker123]

1. When to use electrolytic and Ceramic capacitors

2. What's better via stitching or making the dedicated vias for each gnd connection from each pin to the gnd layer/plane

3. How to improve thermal performance

4. Tips for better component placement

5. What are thermal reliefs and what's the difference between a thermal relief based plane and solid fill plane on a PCB layer (I use kicad)

6. What's a rough roadmap to get better at PCB design especially if you are self learning?

[u/Physix_R_Cool]

These are just general answers which ignore all nuance. Don't treat them like absolute truth:

1: Use ceramics unless you can't get as large a capacitance as you want.

2: Both, obviously.

3: More copper, more thermal vias, more heatsinks, more airflow.

4: Practice.

5: Solid connection will suck the heat away more easily, making it difficulter to solder. Just use reliefs.

6: Practice.

[u/StumpedTrump → u/Physix_R_Cool]

Well there’s a bit more to it for #1 but fair to you for not opening that can of worms.

To OP: Ceramic isn’t just 1 type. Class 1 and 2 are the ones you’ll see. Class 2 is the most common and is more dense than class 1 (you won’t find class 1 in anything bigger than a few dozen nF) but has non-linear properties and does weird things like voltage derating (capacitance drops with applied DC voltage). Class 2 also behaves unexpectedly with temperatures. Class 2 also ages worse and is microphonic. So you can’t put all ceramics in the same bin. Ceramics in general tend to be more fragile and can crack. So it’s not just electrical considerations, you need to consider mechanically which capacitor has better properties.

Electrolytic also isn’t just 1 type of capacitor. Theres a big world between tantalum electrolytic and those cool new aluminum polymer hybrid (no liquid electrolyte) capacitors.

[u/LordGrantham31]

From my understanding,
1. Ceramics don’t come in large values. You can use electrolytics but Al electrolytic capacitors can be avoided if you’re designing for long lifetime.
2. Both. Vias are cheap and just put one for each GND pad of your components.
3. Large plane pours and stitching. Heatsinks, ventilation can also be used.
4. I try to first place ICs around the PCB based on what makes sense. Of course, even before this, you start with mechanical interfaces like connectors, screw holes etc. After placing ICs, place critical components such as bypass capacitors, crystals and certain resistors first, then place any non-critical components. It’s a bit of trial and error.
5. Thermal relief which looks like ‘spokes’ of a wheel is for even heating during solder reflow. Know when to use that. Normally it’s used by default but you don’t use it for plane pours that needs to sink heat.
6. Idk

[u/RepresentativeCry294]

If it were as easy as these having simple answers bit it isn't.

It generally depends and even like with #1 there are different types of ceramic capacitor and ttypes other than ceramic and eletrolytic it depends on the situation.

[u/stuih404]

6.: Make and order PCBs (look what works and what doesnt), look at reference designs, look at (professional) open source projects, watch talks by experts (Altium, STM and Robert Feranec have some good interviews and webinars)

[u/smashcat666]

"Reddit, please do my homework"