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???
09/22/11 04:29
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#183844 - looks promising
Responding to: ???'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            01/01/70 00:00      
   Suggesting....again...            01/01/70 00:00      
      Alas 5V needed and ribbon cables are a bit "rough"            01/01/70 00:00      
   Another Suggestion....            01/01/70 00:00      
   level translator            01/01/70 00:00      
      Alas, "weak output drive" and no input hysterese            01/01/70 00:00      
      TI sn74gtl2010            01/01/70 00:00      
         or NXP GTL2010,GTL2000            01/01/70 00:00      
            looks promising            01/01/70 00:00      
            NXP GTL20xx -> NVT20xx            01/01/70 00:00      
         Need to read more to understand them            01/01/70 00:00      
            looks like the cat's miauw            01/01/70 00:00      
   NXP has ....            01/01/70 00:00      
      I2C or SPI just can't get even close to the huge bandwidth            01/01/70 00:00      
         nope, no I²C clocks            01/01/70 00:00      
            extender, not expander            01/01/70 00:00      
   I have been wondering this myself            01/01/70 00:00      
      Supported capacitance seems to be the snag            01/01/70 00:00      
   Differential SPI            01/01/70 00:00      
      Serial -> buffers on adapter boards is a potential solution            01/01/70 00:00      
   Have you considered programmable logic?            01/01/70 00:00      
      I had suggested this as well            01/01/70 00:00      
         Yes ... I remember that ...            01/01/70 00:00      
            Long life            01/01/70 00:00      
               They seem to live a long time ...            01/01/70 00:00      
                  Adapters            01/01/70 00:00      
                     These aren't necessarily so "huge"            01/01/70 00:00      
                        Not huge in size            01/01/70 00:00      
                           Some of them can handle that.            01/01/70 00:00      
                              Yes and no            01/01/70 00:00      
                                 There are ways ...            01/01/70 00:00      
                                    Body diodes            01/01/70 00:00      
                                       serial termination ...            01/01/70 00:00      
                                          Yes, current- and bandwidth-limiting components used            01/01/70 00:00      
                                             you youing whippersnappers, pay attention            01/01/70 00:00      
            pedantry, again            01/01/70 00:00      
               What would YOU suggest?            01/01/70 00:00      
   Here's a thought ...            01/01/70 00:00      
      Probably            01/01/70 00:00      
         I'd sugest you consider older CPLD's            01/01/70 00:00      

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