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SN74VMEH22501: ringing

Andrea Guitta
Intellectual 290 points
Part Number: SN74VMEH22501

We are using SN74VMEH22501 buffer in a project of ours

 

The master of the bus is a CPU board, and in the backplane 6 I/O slots are available, and (in the example below) only two slots are populated with an I/O board

In the CPU board and in each I/O board we have SN74VMEH22501 buffer.

 

See below the waveform of the signal in input to the SN74VMEH22501 (red) and in output (yellow)

The red signal looks very good to me, instead the signal generated by the buffer shows a lot of ringing.

 

The signals are terminated with 470R/330R divider

 

Please can you explain why (and provide suggestion) I see all this ringing?

 

Is this buffer recommended, too, when we have not so many I/O slots? In figure below it seems like up to 21 slots are used.

We have different backplane configuration: the largest backplane is 6 slot; the shortest has only 1 slot

 

Thanks in advance

Kind regards

 

Andrea

  • 0
    TI__Guru* 96862 points
    Hi Andrea,

    The SN74VMEH22501 has a great deal of drive strength (50/100mA), which is great for large loads, but if you have a lighter load, ringing is very common. This ringing can also be indicative of a long signal trace (high inductance). Can you share a schematic/details of the connections between the devices?