DRV8301 chips of lot number 88ASYCTG4 suspected of high failure rate
Several users and participants of the CFOC2 v0.9 has experienced failure from DRV8301 devices of lot number 88ASYCTG4 from JLCPCB’s SMT assembly service. This was originally thought to be inadequate soldering but has since proven to be something more complicated. This particular lot has shown to have a high failure rate though not necessarily always failing. Symptoms exhibited are audible ringing from the inductor close to the DRV (L1), deregulation of the 5V output from the DRV’s buck converter, and subsequent catastrophic failure of anything connected to the 5V rail (CAN transceiver, ESD diode, 3.3V LDO, ect)
@doomy has discovered a test to recognize bad units before powering on. On an unpowered CFOC2, perform a diode test with a multi-meter that has this feature from supply positive to supply ground and then reverse. Results should be close to the chart below
Good
NEG - POS + 2.615
NEG + POS - 0.555
BAD
NEG - POS + >3V
NEG + POS - 0.576
I am attempting to track down this particular lot number all the way to the manufacturer to see if this was a known bad lot that somehow ended up in JLCPCB’s stock. If you have been affected by this occurrence, I encourage you to contact JLCPCB’s customer support and seek a refund for the failed DRV units.
UPDATED SUMMARY
v0.9 released on GitHub. Beta testing ongoing with success so far.
I’m happy to finally announce the v0.9 release of the Cheap FOCer 2! Special thanks to @bj97301, @NuRxG, and @Davewesh for formatting the repo into something truly outstanding, much better organized, and readable by humans.
Remember that this is still being beta tested (although successful so far). Myself and the other contributors to this project will be making tweaks as we go and as we receive feedback from the community. I hope this community enjoys having this open source hardware available to build, use, sell, modify, and improve.
Capabilities
- 35A continuous and 70A peak with good heat sinking. These are real values. Not marketing numbers
- Up to 50.4V(12s) safe operating voltage. For 20s version take a look at these FOCers.
- Compatible with the VESC Tool for configuration
- Open source enclosure design to come
- “Living” LCSC BOM to come. BOM document to be continuously updated with compatible and stocked components from LCSC
Advantages over VESC 6
- Significantly lower build and BOM cost
- TO-220 FETs allow for big heat sink attachment for better thermal performance
- 2-layer PCB that enables low-cost manufacturing from JLCPCB
- Designed with JLCPCB’s SMT assembly service in mind
- Added optional ON/OFF connector to turn off control circuitry when controller is not in use
- CAN connector changed to 2-pin to avoid improper connections that can cause damage
- ESD protected I/O
- Hardware open sourced
- Designed with direct meme integration
Advantages over Cheap FOCer 1
- VESC 6 based instead of VESC 4.12
- Significantly improved layout to reduce current loops and facilitate low-noise operation of both the power stage and control circuitry for more stable operation
- Has IMU for balancing applications
- Lower profile
- Handles lower inductance motors much better
- All components on the top side except MOSFETs
- Addition of JST connectors to replace pin headers for Servo, CAN, COMM, ect.
- Addition of header for unused GPIO pins
- Micro USB
Disadvantages (that I know of)
- Larger than original VESC 6. Cheap FOCer 2 is about 60mm x 120mm x 14mm without enclosure/heat sink
- Uses custom firmware that’s not currently supported in the VESC project. Will make firmware available on GitHub until Cheap FOCer 2 is added to and supported by the official VESC project.
All this wouldn’t be possible without Benjamin Vedder’s hard work to build on. Please consider supporting him for his efforts through the link below.
https://vesc-project.com/donations
** Funding for essential materials has been achieved but I’m not stopping anyone from helping out. Anything you toss my way helps with unexpected costs and/or helps get this project to completion**
Keep up the work, happy testing!
