Orel ESC reference design BOM in 2023

Support Sapog motor control
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I have printed the Orel ESC pcb’s based on the reference design board files on github. One thing to note is that the BOM looks like it was compiled several years ago (before the pandemic supply constraints + chip shortage).

All of the components can now be found, albeit with some substitutions that I am not 100% sure about

  1. I was thinking of substituting the Infineon FETS with these: https://www.ti.com/lit/gpn/CSD18512Q5B

The TI FETS have the same dimensions as the Infineon ones and the footprint looks close if not identical.

  1. I could not find in the original BOM JST-GH 4 pin female surface mount. I did find an alternative that looks very close to the original footprint here: https://www.jst-mfg.com/product/pdf/eng/eGH.pdf

Notice the PCB design has the oval shaped pads on either side but the datasheet shows them as rectangular. Is this going to be problematic even if the pin spacing on the signal pads are the same?

  1. The original crystal oscillator used is the schematic is generic, but I assume one like this could work given the dimensions, but would it need to be 3.3v tolerant? https://www.digikey.com/en/products/detail/txc-corporation/7M-24-000MAHV-T/5126384

  2. I found this 5mOhms current shunt resistor but not sure if the footprint is correct, the listed one in the BOM is generic: https://www.digikey.com/en/products/detail/stackpole-electronics-inc/CSNL2010FT5L00/1788098

Last but not least the STM32F105RCT7. Is the 256KB of flash going to be adequate for the Sapog firmware? I plan to use these ESC’s in a Cyphal application on a multirotor: https://www.digikey.com/en/products/detail/stmicroelectronics/STM32F105RCT7/2214610

Also here are pics of the PCB’s (I printed 20 of them) 1oz inner and 1oz finish copper

IMG_E3205
IMG_E3205828×482 106 KB

IMG_E3206
IMG_E3206828×471 102 KB

pcbspecs
pcbspecs928×364 11.6 KB

1 Like
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The alternatives look okay but YMMV. The shape of the connector pads is hardly significant. 256 KiB of ROM is sufficient.

Might we interest you in Mitochondrik instead?

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I have looked at the Bloxa design and it looks like it would be suitable for the platforms I want to use, however since this is for a personal project I need to keep costs down.

I calculated the cost to make 20 of Orel esc’s immediately (with extra parts to build more in the future) to be around $30-40 a piece including the PCB’s. Roughly $7 for the PCB and $20 budgeted for parts (including passives).

The mitochondrik module is around $70 USD and that does not include a carrier board for the module so it is priced well above what I am aiming for. Perhaps something I would explore if a client wanted a more advanced custom ESC built in lieu of the cheap off the shelf stuff.