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henrikssn / TurboCAN

This is the official repository for the TurboCAN controller board, designed specifically for the Voron AfterBurner toolhead but can also be used on similar toolheads using NEMA17 steppers.
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Fix source and drain pins on AON7400A heater MOSFET. #3

Closed robets closed 3 years ago

robets commented 3 years ago

This PR fixes the reversed source and drain pins on the AON7400A heater MOSFET for #2.

I rotated the footprint to put the drain pins closest to the heater connector, and routed the gate around to the opposite corner. Routing could probably be improved, I'm somewhat of a novice on PCB layouts.

robets commented 3 years ago

I'm not sure if I've done this correctly for KiCad. The only way I could find to add the thermal vias and pad was to modify the footprint for the component. I copied the footprint to "DFN-8-1EP_3x3mm_P0.65mm_EP1.7x2.05mm_Thermal_Pad" to keep it optional.

Added a 4x4mm pad to the opposite side with 3x2 via grid. Moved the nearby related pads to keep good continuity with the ground pour.

image

As a side note, the power handling increase going from the AO3400A to AON7400A is probably lost due to the SS54 diode on the power input being limited to 5A. Using another AON7400A could be suitable for reverse polarity protection instead of the diode. BOM cost increase would be fairly small since the extended part cost of the AON7400A is already done by using it once.

I'll open a separate PR for that if I can figure it out.

henrikssn commented 3 years ago

Thank you, looks great! Lets follow up in #4 on improving the reverse polarity protection.