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Forum Index : Microcontroller and PC projects : CH334F in USB reference design - major issues - don't order
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| matherp Guru  Joined: 11/12/2012 Location: United KingdomPosts: 10062 |
I've just received my batch of the updated reference design with the RP2350B onboard. As in the original this board includes a CH334F 4-port USB hub. More than 5 orders have been placed using this chip all of which work perfectly. However, the hub in the boards from birefringence's recent order didn't work. My hub also doesn't work. I have moved a known good CH334F from a working board and soldered it to a board from the current order (not easy).  This now works. I then soldered the suspect CH334F to the known good board and that no longer works. Taken together with the evidence from birefringence's order, it appears that there is definitely a bad batch of CH334F. I've filed a complaint with JLC who will contact LCSC and will wait to see what happens. I'll report progress here. In the meantime I would recommend not ordering and boards using this chip from JLC. |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3996 |
Good grief! Definitely not easy. John |
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| Amnesie Guru Joined: 30/06/2020 Location: GermanyPosts: 528 |
Hello, though it is possible that this could be also happen with a none-chinese IC, but again; I would not trust any of those chips at all. I rather pay the extra money for proper chip brands. I really feel the hard work of desoldering those...  Greetings Daniel |
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bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2945 |
Hi Peter, All, One of the reasons I use the FT231 chip. It is quite a lot cheaper than the often cloned FT232RL (but not as cheap as the CHxxx) and to my knowledge has not, yet, been cloned by our friends in China etc. I have had quite a few problems with several of the CHxxxx type Chinesium serial to TLL in the past and hate them with a passion. The chip in my CNC mill(s) work but often change their USB port numbers from one boot to another.. a right royal PiTa. Take care All, Regards, Mick (the big one) . Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10062 |
All: If you have had boards made to my USB reference design with the 4-port hub please PM me the JLC order number for the smd assembly (starts SMT). You can get this from the order history on your JLC account. Please include the order date and whether the hub works properly - thanks |
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| davematt Regular Member  Joined: 27/09/2011 Location: AustraliaPosts: 55 |
It seems Silicon Chip have bought a bunch of these boards too. No word of a solution yet… Glad we are not hanging by the unmentionables…:) D |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9482 |
I thought that LCSC only stocked genuine parts? You'd kinda want to do that, if you are in the business of building prototypes.... Smoke makes things work. When the smoke gets out, it stops! |
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| va7ehf Newbie  Joined: 23/07/2020 Location: CanadaPosts: 6 |
Ouch, I did not see this thread before I ordered 5x assembled HDMIUSB boards through JLCPCB. The USB hub on my board is not working. I can get USB functionality by using an OTG adapter in the PROG port, though. Is there any suggested rework that can fix my boards? |
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| birefringence Newbie Joined: 25/02/2025 Location: GermanyPosts: 23 |
You can try to remove R54 and R55. This worked for me. It will disable the over current detection of the USB controller but should have no other side effects. |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10062 |
Silicon chip have been appraised of the issue and will be removing R54 and R55 before shipping. As birefringence says this just disables the overcurrent detection but as the supply is also fused (resetable) is completely benign. There are variants of the CH334 without this protection so this feature is just a "nice-to-have". My design for the RP2350B, just released, continues to use the CH334F but with the overcurrent protection circuitry removed from the design (no R54/R55) It appears the parts are completely genuine, just a batch with different (wrong) characteristics. |
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| va7ehf Newbie Joined: 23/07/2020 Location: CanadaPosts: 6 |
birefringence, thanks for the suggestion! it's working for me.  |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 10062 |
For info, I've designed a 4 port hub based on the FE1.1S and ordered some from JLC. Assuming this plays nicely with the PicoMite I'll update the designs using this chip. Schematic a7431364-ab62-47da-9336-dd0b182ab3b9.pdf  |
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