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Recommend LVDS or RS422 / RS485 Driver and Receiver Pair for ~30MHz Signals

Intellectual 660 points

Replies: 2

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Hello TI-Community,

i have a 'art project' (costume) where i have some LED-Drivers (TLC5957) about 2meters away from my controller.
The Drivers have multiple Signals (GrayscaleClock, SignalClock, SignalData, Latch) that can go up to 30MHz.
So my Idea was to use RS485 / RS422 or LVDS to transmit this over the 2meter.

My Power Supply and IO Voltage is all 3.3V.
Can you Recommend any Drivers for this type of Application?
do i have advantages choosing one over the other technology?

for RS422 i have found this Pair:

for LVDS i have found this Pair

is either a good choice?
or are there any other better suited parts?

additionally i have found this Info:

i hope you can give me some tips :-)

sunny greetings
stefan

:-)
  • Hi Stefan,

    Sounds like a high-tech costume. Maybe you can show it to us once you get everything working. :)

    At 30 MHz, either LVDS or RS-422 (or RS-485, which is similar) should be able to communicate over a 2-m cable, and the devices that you've selected are both good choices. In general, though the main trade-off is that RS-422/485 uses a higher differential signal amplitude compared to LVDS. This helps in working with longer cables and can translate to better noise immunity. It also translates to higher power, though, and because of the larger signal swing the transition times tend to be slower (limiting the maximum rate of operation). So while 30 MHz is towards the upper end of what RS-422/485 transceivers are typically designed to support, it is well within the capabilities of most LVDS devices. (Using a device capable of higher speeds may be a good idea if you expect your system to be sensitive to signal timing.) Since RS-422/485 is generally used in more industrial environments, it is typically a little more robust against things like short-circuits to higher voltages, ESD strikes, etc.

    Another factor to consider if your channels need to be aligned in time (for example, if you have parallel data and clock lines) is the channel-to-channel timing skew. This is something that is specified for most multi-channel parts.

    Regards,
    Max
  • In reply to Max Robertson:

    Hi Max,

    thanks for your message!
    i will try the LVDS way :-)
    thanks for your explanations, that did really help me to get a better overall image!
    and if i get it working i will post here ;-)

    sunny greetings
    stefan
    :-)

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