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Richard Erlacher
09/21/11 22:29
Read: 182 times
Denver, Co
USA


 
#183844 - looks promising
Responding to: Stefan Kanev's previous message
Description
the datasheet said:
"

The GTL2010 provides ten NMOS pass transistors (Sn and Dn) with a common gate (GREF) and a reference transistor (SREF and DREF). The low ON-state resistance of the switch allows connections to be made with minimal propagation delay. With no direction control pin required, the device allows bidirectional voltage translations any voltage (1 V to 5 V) to any voltage (1 V to 5 V).

When the Sn or Dn port is LOW, the clamp is in the ON state and a low-resistance connection exists between the Sn and Dn ports. Assuming the higher voltage is on the Dn port, when the Dn port is HIGH, the voltage on the Sn port is limited to the voltage set by the reference transistor (SREF). When the Sn port is HIGH, the Dn port is pulled to VCC by the pullup resistors.

All transistors in the GTL2010 have the same electrical characteristics, and there is minimal deviation from one output to another in voltage or propagation delay. This offers superior matching over discrete transistor
voltage-translation solutions where the fabrication of the transistors is not symmetrical. With all transistors being identical, the reference transistor (SREF/DREF) can be located on any of the other ten matched Sn/Dn transistors, allowing for easier board layout. The translator transistors with integrated ESD circuitry provides excellent ESD protection.

"


This might be exactly what's called-for. I am concerned about the end-effect that causes the MCU to provide the current source/sink with which to drive a cable, though. There's always a "gotcha" isn't there? An individually direction-configurable I/O buffer consisting of a typical CPLD would generally have more drive current than would a typical MCU. Maybe by picking the correct MCU, this problem goes away.

RE


List of 40 messages in thread
TopicAuthorDate
Bit-configurable transceiver chips        Per Westermark      09/12/11 02:28      
   Suggesting....again...      Michael Karas      09/12/11 05:35      
      Alas 5V needed and ribbon cables are a bit "rough"      Per Westermark      09/12/11 06:54      
   Another Suggestion....      Michael Karas      09/12/11 05:59      
   level translator      Jan Waclawek      09/12/11 06:21      
      Alas, "weak output drive" and no input hysterese      Per Westermark      09/12/11 07:30      
      TI sn74gtl2010      Stefan KAnev      09/17/11 02:18      
         or NXP GTL2010,GTL2000      Stefan KAnev      09/19/11 01:24      
            looks promising      Richard Erlacher      09/21/11 22:29      
            NXP GTL20xx -> NVT20xx      Jan Waclawek      10/04/11 00:57      
         Need to read more to understand them      Per Westermark      09/20/11 02:04      
            looks like the cat's miauw      Erik Malund      09/21/11 07:45      
   NXP has ....      Erik Malund      09/12/11 13:28      
      I2C or SPI just can't get even close to the huge bandwidth      Per Westermark      09/12/11 14:01      
         nope, no I²C clocks      Erik Malund      09/12/11 14:21      
            extender, not expander      Per Westermark      09/12/11 14:37      
   I have been wondering this myself      Justin Fontes      09/12/11 16:18      
      Supported capacitance seems to be the snag      Per Westermark      09/12/11 17:23      
   Differential SPI      Jez Smith      09/16/11 09:39      
      Serial -> buffers on adapter boards is a potential solution      Per Westermark      09/16/11 14:41      
   Have you considered programmable logic?      Richard Erlacher      09/19/11 14:08      
      I had suggested this as well      Michael Karas      09/19/11 14:33      
         Yes ... I remember that ...      Richard Erlacher      09/19/11 23:43      
            Long life      Per Westermark      09/20/11 01:59      
               They seem to live a long time ...      Richard Erlacher      09/20/11 09:22      
                  Adapters      Per Westermark      09/20/11 10:16      
                     These aren't necessarily so "huge"      Richard Erlacher      09/20/11 19:52      
                        Not huge in size      Per Westermark      09/21/11 01:49      
                           Some of them can handle that.      Richard Erlacher      09/21/11 22:34      
                              Yes and no      Per Westermark      09/22/11 04:53      
                                 There are ways ...      Richard Erlacher      09/22/11 10:55      
                                    Body diodes      Per Westermark      09/22/11 16:39      
                                       serial termination ...      Erik Malund      09/23/11 07:36      
                                          Yes, current- and bandwidth-limiting components used      Per Westermark      09/23/11 08:25      
                                             you youing whippersnappers, pay attention      Erik Malund      09/23/11 11:45      
            pedantry, again      Andy Peters      09/20/11 11:13      
               What would YOU suggest?      Richard Erlacher      09/20/11 19:45      
   Here's a thought ...      Richard Erlacher      10/17/11 03:03      
      Probably      Per Westermark      10/17/11 15:51      
         I'd sugest you consider older CPLD's      Richard Erlacher      10/17/11 19:14      

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