5 Boards with Assembly are on order at JLC

A project log for Brushless Actuator (Arduino-Compatible)

Ardunio-Compatible M0/Zero/SAMD21 with FET Driver, MOSFETs, Absolute Magnetic Encoder, USB and RS485 comms. ~$US50

Paul GouldPaul Gould 06/14/2020 at 16:195 Comments

Size 50mm square and 58mm round

On board absolute magnetic encoder is either MA730, MA702, AS5147 or AS5047 There are others in this range.

Connectors clockwise from the top

The connectors are multi footprint JST. Through hole straight / right angle, SMT straight / right angle

Pitch can be either 1, 1.27, 1.5, 2 or 2.54mm

Connectors on the back (from the bottom)


Calum wrote 08/06/2020 at 14:37 point

Insane density and diligently laid out, smashing job!

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Paul Gould wrote 08/06/2020 at 15:20 point

Thanks. I have to do a new run of these boards soon with some minor fixes. I might try some 0402 caps and resistors.

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Calum wrote 08/06/2020 at 16:30 point

Sounds like that would save you a reasonable amount of room - are there any large drawbacks apart from making self-repair more difficult?

I'm in the process of designing a 4-layer NEMA-17 mounted board for 3D printing too, and also hope to get them made by JLC PCB. It's great to see this design go from schematic to real PCB - puts faith in the process.

How are those NVTF MOSFETs and ground pads performing wrt heat dissipation? I've been eyeing them up in comparison to the Infineon BSC022

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Calum wrote 08/06/2020 at 16:38 point

Also - did you happen to have any issues with PCB flex and the proximity of your MOSFETs to the mounting holes? Looks like you're pressing right up to the courtyard of the components there (which is what I'd be tempted to do).

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Paul Gould wrote 08/07/2020 at 10:34 point

The assembly failure rate can be higher with 0402 and they are can be a bit fragile. JLC pcb and assembly went very well and so fast. I just have to check their design notes more carefully with the diode orientation.

I haven't put too much current though the FETs (about 5A max). Most FETs with a low R-on and low gate charge are suitable. Just make sure the gate current is enough so the switching losses don't get too high.

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