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Fake SIPEX SP3232E (RS232 Tx/Rx) [message #6395] Mon, 17 June 2019 10:46 Go to next message
just4fun is currently offline  just4fun
Messages: 215
Registered: May 2017
Location: Dark side of the Moon
Senior Member
I was testing a 2-channels RS232 adapter for my FPGA board, when I saw this "miracle":

/forum/index.php?t=getfile&id=1430&private=0

If any signal from the RS232 is at a positive voltage and the board is not powered, there is a leakage current to VCC that turns on the led (power indicator).

More, if a VCC = 3.3V is applied the board doesn't work for speed greater than about 300 bps.
Applying a VCC = 5V the board works as expected.

I've used a couple of SP3232E (marked SIPEX that should work @ 3.3V and 5V according to the spec, ah ah...) that I bought from Aliexpress more that one year ago and not used until now:

/forum/index.php?t=getfile&id=1431&private=0

I really think that is another fake RS232 IC...

I've just removed both the ICs and cleaned the pads...

/forum/index.php?t=getfile&id=1429&private=0

...so probably tomorrow I'll try with a new lot of SP3232 from EXAR bought from TME (www.tme.eu).

We'll see...

[Updated on: Tue, 18 June 2019 05:29]

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Re: Fake SIPEX SP3232E (RS232 Tx/Rx) [message #6398 is a reply to message #6395] Tue, 18 June 2019 10:39 Go to previous message
just4fun is currently offline  just4fun
Messages: 215
Registered: May 2017
Location: Dark side of the Moon
Senior Member
The new SP3232E arrived today at my office from TME using DHL Express, so I've re-soldered these on the previous board...

/forum/index.php?t=getfile&id=1434&private=0

...and now the board works at 3.3V and 5V @ 115200 baud and without any "strange" current leakage when not powered... Very Happy

Here the good SP3232E from TME (in the bottom) compared with the fake one from Aliexpress (upper in the photo and not soldered):

/forum/index.php?t=getfile&id=1433&private=0

They look very similar but some differences are anyway visible.

Things happen... Rolling Eyes
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