AVR-Chat

I agree with your first post. I didn't find the TI white paper very
useful. The FET switch discussion using the CB3T bus switch lead to a
dead end in terms of useful ICs that could do the job.

> I think the only logic level translation problem that doesn't have a
number of straightforward solutions is the bi-directional, three-state
one where there is no signal to explicitly give the direction of logic
flow across the translation boundary.

Yup and is exactly the problem I am looking at for my current design.

> The generally proposed solution is a variation of the uni-directional
translator using an N-Channel MOSFET in common-gate mode.
> In the bi-directional variation, "input" and "output" are replaced
with "left" and "right".  The source also has a pullup to the "left"
logic supply.
> My question for the non-"digital only" folk is this ... will just
about any MOSFET (with an appropriate threshold) perform well in this
circuit?

I have chosen the BSS138DW (dual MOSFET) which has a gate threshold of
1.2V. Does any see a problem with using this device for 2.7/3.3 to 5V
level translation?

To answer your question I googled the following paper:
http://www.vartists.com/engineering/N-MOSFET_bidirectional_level_shifter\
_analysis.pdf