ONET4201PA: Copper Rise time on ONET4201PA output

Hi Jared,

could it be, that the increased rise time is caused by your measuring equipment?

How do you measure the rise time?

Kai

We measure rise time after roughly 1 inch of circuit board and a small cable to a very high speed differential scope probe. Again the data is at 340 Mbps and the rise time we are seeing is 320ps through the diff scope probe. I'm certain the scope probe is fast enough.

Jared

Hi Jared,

the chip has 50R series termination output resistors installed. In combination with the scope probe capacitance and stray capacitance this could result in an increase of rise time.

Can you make a measurement using 50R technique (50R cable and 50R scope input)?

Kai

Hi Jared,

Has the issue been resolved? If not, can you please let us know the following?:

1. Have you tried the measurement using the 50R technique as Kai suggested above?
2. Can you measure the rise time at higher data rates, for instance @ 1 Gbps and 4 Gbps?
3. What is the value of the ac coupling caps used on the DOUT lines?

Thanks,
Sri