I'm trying to create an interface PCB to a 32 channel USB GPIO device which has 3.3v IO, and I want the flexibility to use 1.8, 3.3 or 5v - across all pins, or at most in 2x banks of 16 - I don't need different voltages on a per-pin basis.
Speed-wise I'd be looking for at most 1MHz switching frequency, but as low as 200kHz would probably be fine.
When searching through Farnell (UK version) I've found lots of 16-channel level shifters that are technically bi-directional, but only with a switchable direction using a DIR pin handling an 8 channel bank. I need something that will give true bi-directionality on each pin without having to set the direction.
As an example, what I currently use for level shifting is this SparkFun board: SparkFun Logic Level Converter - Bi-Directional but this requires a 'low' side and a 'high' side. I suppose I could shift everything to 5v and then back down to 3.3v, but I'd prefer a simpler packaged solution.
Is there some terminology I'm missing that would help me narrow down my search to find what I need? If it even exists, that is.