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  • TI Thinks Resolved

TTL differential demux 1:2

Prodigy 150 points

Replies: 5

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Hello,

I had a requirement where i need a 1:2  differential TTL IC.

My input is 100MHz differential TTL.

I need to have same signal that should be repeated twice at output with same characteristics. 

Below is my requirement. Can you please suggest any IC.

input and output(A&B) shall be same(Amplitude and frequency).

Thanks,
muni

  • Hi muni,

    We don't have exactly a chip that can do that however I might have a solution.

    If we use a 4 channel buffer, we can achieve what you are looking for.

    You can connect one signal of the differential input pair to channel inputs 1 and 3 and the other signal of the differential input to channel inputs 2 and 4. Then you will have differential outputs on channels 1 and 2 and channels 3 and 4. 

    You will need to perform some tests on channel to channel skew depending on what frequency you are operating at. Typical channel to channel skew is much less than a nano seconds.

    We have the SN74HC125 or 126 or the SN74AHC125 or 126 which are 4 channel buffers. 

    Thanks!

    -Karan

  • In reply to Karan Kotadia:

    Hello Karan,

    Thanks very much for your inputs.

    Currently i am using SN74S240. While simulating with this IC, i could not able to get good results at 100MHz square wave.

    This buffer ICs are good till 20MHz square wave, Do you have any suggestion for higher bandwidth octal bus buffer driver.

    Thanks,

    muni

  • In reply to Muni Pavan Kumar Reddy Kona:

    Hi Muni,

    100 MHz is extremely fast for 5V signals. If you have a 3.3V supply available in the system, you could input your 5V signals to an SN74LVC244A supplied with 3.3V and it will output a TTL compatible (3.3V) signal. This device can operate at100 MHz.


    Looking for a low voltage translator? Check out the AXC family that supports 0.7V to 3.3V translation!

    The Logic Minute training page has videos on many interesting topics that all are kept shorter than 5 minutes.

  • In reply to Emrys Maier:

    Thanks Emirys.

    Will SN74LV541AT work till 100MHz? Currently we are using this chip for design.

    Thanks,
    Muni

  • In reply to Muni Pavan Kumar Reddy Kona:

    Hi Muni,

    100 MHz is borderline for the SN74LV541AT. You will have to make sure there is minimal load on the channel and optimal traces. I would not only test the part in simulation but also on bench before confirming.

    Thanks!

    -Karan

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