#2100

[@Manf-ft6zk]

Very interesting, the fun part will be the mounting of the chips. In the title the filter is named digital capacitor filter while the name switched capacitor filter like on the board is normally used for a different principle where capacitors are switched between to points for charge transport faster than the signal frequency to adjust the current that is passed. You can name the filter of course any way you like.

[@slagmaker6780]

I add a little extra pad length on such small parts when doing hand solder work. maybe 2x pad length. Sometimes use an oven but often do it with just small solder tip.

[@Mr.Leeroy]

stick to QFPs then. This is a 2/3 job for a hot air gun, the rest is pre-tinning and maybe solder drag touch up.

[@SirEngelmann]

Awesome project, and thank you for introducing us to those tunable capacitor IC's! However, I am not sure about your microstrip path layout. The forks and bends are local discontinuities and (depending on the operating frequency) could in theory lead to significant reflection through impedance mismatch. Maybe you could place the shunt L's and C's right onto the main microstrip so that they act more as lumped elements, also the ICs could be rotated by 45 degrees such that the corner pins can be connected with shorter distance. Greetings!

[@IMSAIGuy]

it's only 150 MHz, no worries

[@EclipseMusic94]

Missing pullup resistors on the i2c bus?

[@CrazyLabs]

When the pins i2c of the microcontroller is configured as i2c, the pull up resistors are automatically set up internally

[@ralphj4012]

External pullup requirement mentioned in the datasheet, but seemingly not present (or hiding) on the prototype.

[@andrsam3682]

​@@ralphj4012 they could be installed on dispay

[@IMSAIGuy]

yes, the display board has them. watch my prototype last video, no resistors.

[@bobdoritique7347]

Cool project, very nice. Solder paste for your tiny circuit?

[@dilbertnewton6864]

What board finish did you go with? Hasl, enig.

[@IMSAIGuy]

standard hasl. maybe enig would have been better

[@d.jeffdionne]

@@IMSAIGuy I find ENIG can be helpful for SMD hand assembly... but only a little for QFN. The reason is my technique is to specify the paddle via unplugged and fairly large, and then I just tin all the QFN pads. Hot air the thing with lots of flux, and if I've gotten the tinning even, the QFN will self align due to surface tension (as it's supposed to, just give it a tweak) without the paddle solder puddle floating it too high for the pads or becoming disconnected itself. Any excess solder on the paddle pad goes down the via.

[@tonttu303]

So what are the secret chips

[@georgealdredge2806]

Did you watch parts one and two of this series?

[@IMSAIGuy]

kzbin.info/www/bejne/nnXNq3eIn76irNk

[@TriciaLindstrom123]

Are you purposefully hiding what software you are using? Why?

[@gustavomariz7769]

to make the pcb he used kicad, he has talked about it other times before. I dont think he's hiding it

[@IMSAIGuy]

you must be new to the channel. I use KiCAD all the time.

[@IMSAIGuy]

here are boards I've designed: www.pcbway.com/project/member/?bmbno=32645027-AC83-49 learn KiCAD: kzbin.info/www/bejne/e3iQkJKqfsecadEsi=BOVxW3PvDfMfVTSp

[@IMSAIGuy]

if you are interested in watching me do a complete design in KiCAD, watch this series of 10 videos: kzbin.info/www/bejne/eH_Cdp-EgN17p8Usi=5WCAMxYBXwPYhzef

[@minime9400]

@@IMSAIGuy Now I know why, because you cropped the video and the Menu bar was left out. But a more humble approach to that would be a simple "what program are you using".

[@MaxPivovarov]

This will not work perfectly, because he has a poor printed circuit board design