• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Subscribers 33 subscribers
  • Views 659 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

maximum bit rate for 75lbc173

Avi Shefi
Prodigy 40 points
Other Parts Discussed in Thread: SN75LBC173A, SN75LBC173

Hi,

What is the maximum bit rate that I can work with 75lbc173?

Thanks

Avi

 

  • 0
    TI__Mastermind 21801 points

    Hi Avi

    We can characterized the SN75LBC173A devices at 50MBPS. This means the device was characterized across process, voltage and temperature. If your specific application has tighter temperature range, tighter voltage range, it is possible to operate the device at faster speeds. This will all obviously be very dependent on the network you have set up and how much parasitic capacitance is on the network due to cabling and other devices.

    If you take a look at Figure 10 we show the device operating at 50MBPS with plenty of time for the Y line to settle. Also Figure 8 shows the supply current verses signaling rate for different VCC levels all the way up to 100MBPS.

    Hope this helps!

    John

  • 0 in reply to John Griffith
    Prodigy 40 points

    Hi John,

    I have a circuit with 75LBC173 Not 75LBC173A on it.

    The question is what is the maximum bit rate of 75lbc173.(I see 10Mbps).

    And another question, Can I replace the 75lbc173 with the 75lbc173a?

    Thanks

    Avi

     

  • 0 in reply to Avi Shefi
    TI__Mastermind 21801 points

    Hi Avi,

    You are correct, the max speed we guarantee and characterize the device at is 10MBPS. But just as I said before, depending on your system the device can be used at higher speeds.

    You can drop in the SN75LBC173A for the SN75LBC173 device. They are functionally and pin to pin equivalent. There are only small differences in the absolute maximum ratings and recommended operating ratings.

    Thanks,

    John

  • 0 in reply to John Griffith
    Prodigy 40 points

    Hi John,

    Thanks for the fast responce, and to be more specific.

    I have an old design (Not mine), whith 75lbc173, that is running at 23Mbps.(Clock of 11.5Mhz).

    Does the device can withstand such frequency? or should if will be better to replace it with 75lbc173a?

    Looking at few samples with Oscilloscope seems no problem, Did i receive a good batch of components?

    How and If can I guarantee the work of the 75lbc173 at 23Mbps?

    Thanks

    Avi

     

  • 0 in reply to Avi Shefi
    TI__Mastermind 21801 points

    Hey Avi,

    If the network is short and clean, there is no reason the original SN75LBC173 will not be able to go faster than 10MBPS. As you can see on page 7 of the datasheet a current vs. frequency plot was made that went up to 30MHz (or 60 MBPS). Is your network a point to point, short network, supplying a clock? Is your 5V Vcc line well regulated and doesn’t vary much? These system level characteristics will make it more likely the device will not have issues at higher speeds.

    I understand your concern and I think the issue is, we are not guaranteeing the SN75LBC173 device to work across all temps, voltages and process corners at 23MBPS, and I will not be able to do so. If what you are looking for is a guarantee, I would suggest moving to the SN75LBC173A device. It is fully characterized and guaranteed to communicate at your higher speed.

    Thanks,

    John