I just built a prototype of a board that has a multiplexer for a fast linear signal, and after some tinkering, found the slowest thing is the multiplexer chip. I am using a TI/Burr-Brown MPC506A. This was the only 16:1 analog multiplexer I could find that had any hint of a reference to speed/settling time value in the data sheet. I think I've got something that is useable, but it would be nice to do better. (This is for remote inspection of signals via oscilloscope, so there's no specific value I need, just "better".) Anyway, this is running off +/- 5 V supplies to be compatible with the rest of the board. One trick I came up with was putting a 1K load on the output of the mux, and raising the gain of the buffer amp. This got the performance up to the tolerable level. The signals in question have 5-10 ns risetimes, and an about 20 ns wide pulse leading a slower response from a detector. We pretty much lose all of that leading spike with the current mux chip, and would like to be able to see at least some of it on the scope.
If there is some other mux chip that has a much higher bandwidth, and especially if it is pin-compatible with the MPC506/DG506 pinout, that would be great!
Thanks in advance for any pointers,