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Michael Karas
04/04/12 05:34
Modified:
  04/04/12 05:42

Read: 811 times
Beaverton Or
USA


 
#187004 - Totally 100% Agreed
Responding to: Oliver Sedlacek's previous message
You have already demonstrated that you can hook things up in one layer from a connectivity standpoint. This means that you can flood in a FULL Ground Plane on a two layer board and then be able to significantly improve the Power connections on this board and get the bypass closer to the chip pins that need it. Extending Oliver's advice I would suggest that you consider SMT caps for the RS232 level translator chip as well.

I think that this total circuit needs GND plane under it. Not just the USB/FTDI chip parts.

I have used this FTDI chip in several designs with 4 layer boards and had zero problems with them. In one case there were two of the chips used on a board behind a 1->4 USB hub chip inside a piece of lab test equipment that has two 20A SSRs in it perform power switching to server computers under test. We did not experience any USB upset other than the constant issues suffered by USB Comm type devices due to sudden removal of the USB cable while the port is open. The host system software guy for this test setup has made the software smart enough to detect when the sudden removal happens and then invoke system functions that mimic what you can do in Device Manager to forcibly remove hung USB connection so that on next insertion the system can reliably reconnect the same Comm port back up to the running application. Nearly a thousand of these test systems are in use and there has not been any problems with hung FTDI chips.

Michael Karas



List of 36 messages in thread
TopicAuthorDate
FTDI F232RL Noise issues      Raj Nambiar      03/31/12 08:42      
   GND,cables      Stefan KAnev      03/31/12 11:51      
      of this is it, then      Erik Malund      03/31/12 14:19      
   leakage effects..      Jim Granville      03/31/12 16:46      
      Thanks for the comments..      Raj Nambiar      04/01/12 02:02      
         changing the serial port data....      Stefan KAnev      04/01/12 05:11      
         cable, bought off the shelf      Andy Neil      04/01/12 09:00      
            Test standard solutions      Jim Granville      04/01/12 14:54      
               Options..      Raj Nambiar      04/01/12 23:44      
                  VCP /D2X      Stefan KAnev      04/02/12 03:37      
                     Problem exists with both drivers      Raj Nambiar      04/02/12 08:34      
                  Aten serial to USB cable uses a FTDI chip      Kalpak Dabir      04/02/12 04:16      
   FTDI chip ESD sensitivity        Oliver Sedlacek      04/02/12 06:13      
      Thanks Oliver...      Raj Nambiar      04/02/12 08:30      
         Zeners are slow      Erik Malund      04/02/12 08:59      
         show Your circuit      Stefan KAnev      04/02/12 11:04      
            F232 is USB powered but.. + circuit      Raj Nambiar      04/03/12 01:32      
         USB Isolator Chips      Neil Kurzman      04/02/12 21:50      
            Isolators      Raj Nambiar      04/03/12 02:00      
         Better than zeners      Oliver Sedlacek      04/03/12 07:30      
            just a thought      Erik Malund      04/03/12 07:45      
               Layout      Raj Nambiar      04/03/12 22:13      
                  VCP/Direct drivers      Raj Nambiar      04/03/12 23:49      
                  Layout attached      Raj Nambiar      04/04/12 00:51      
                     It's a high speed circuit !!!!      Oliver Sedlacek      04/04/12 05:09      
                        Totally 100% Agreed      Michael Karas      04/04/12 05:34      
                           the trouble with schematics ....      Erik Malund      04/04/12 07:36      
                              Bandwidth limitation      Per Westermark      04/04/12 09:08      
   22 ohms between serial port ground and FT232 ground helps...      Raj Nambiar      04/05/12 23:58      
      of course it does      Erik Malund      04/06/12 08:01      
         Erik,      Raj Nambiar      04/06/12 09:45      
            Links please      Bert Van Den Berg      04/13/12 13:44      
               Link...      Raj Nambiar      04/16/12 00:12      
                  Solved      Raj Nambiar      06/15/12 23:59      
                     Magnetics      Per Westermark      06/16/12 02:08      
                        Ethernet input is connected to serial port ground      Raj Nambiar      06/22/12 08:56      

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