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THS3091 (TSW3070) full scale step response question

Other Parts Discussed in Thread: THS3091, OPA695

A customer has expressed some interest in the TSW3100 and TSW3070 EVMs and will likely buy a set up for experimentation. I was asked though how fast they can create a 6V edge with this setup. Assuming prop delays are not important and the amplifier will be the limiting factor in producing this edge I can use the slew rate of the THS3091 (5000V/us) to estimate it should be able to slew 6V in 1ns. Also, could he use the transformer output and achieve a faster rate? I've made a few assumptions in this statement though.

Do we have any measured data of these EVMs? What is our best guess to the question: 

"How fast can we create a 6V pulse?"

BTW, this is the second time this question has come up. Both customers asking this are in the ATE end markets. Perhaps future EVM work can more directly target or accomadate generating high speed edges.

  • The amplifier SR varies depending on the voltage step and the data sheet has graphs like the one attached, which is probably close to what would be needed.

    It shows SR is just under 3k with 6V step so rise/fall time will be about 2nS. The OPA695 that is also on the TSW board has about twice the SR for the same step so should be about 1ns rise/fall time.

    Since the DAC has 220ps rise and fall time the amplifier will limit this. I don’t think there is any similar limiting factor in the xfmr since it is a passive device and it should give the fastest edge only at lower current drive capability.