cheap fast logic level shifter

Good idea. I concur with using it as a plain diode—a transdiode is a feedback amplifier, with all the pluses and minuses that entails. The BCX70 is fairly slow, so I’d expect it to slow down the edges a bit if wired that way.

Cheers

Phil Hobbs

It's just a diode drop, and it's bypassed.

It's interesting that the BE and BC diodes seem identical on the BCX70, and reverse beta is high. All I want here is one tiny PN junction to give me about 0.7 volts at minimum current.

If I don't want the collector dangling, I could connect it to the emitter. That would cost about 50 mV.

I have a team of engineers researching whether our FPGA can natively source terminate the ribbon cable.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

Spice says it costs 4 mV.

Connecting base to collector costs 50 mV.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

Is your external logic TTL or HCMOS? Only in the latter case you need level shifters...

Past the coax connector is unknown customers.

The ideal pulse generator has programmable Vlo and Vhi and selectable

I could simply do 3.3v and 50r. That would be easy.

Some people don't want the PPG to be too good such that it might impact sales of our existing products. That's always a dilemma. I like to design things, and I figure that if anyone competes with our products, it ought to be us.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics