LCX logic

I don't see why you can't run this device at 3.3V. In the datasheet it clearly states :

'The LCX541 is designed for low voltage applications with capability of interfacing to a 5V signal environment.'

So run it at 3.3V and just feed it directly from the 5V logic (it's designed for it) or perhaps use a small series resistor if you're feeling paranoid. Of course, if you want the speed you won't want the resistor :)

I am looking at the Fairchild part and it doesn't have the input diode to Vcc, so it won't power itself via the inputs.

Cheers

PeteS

You need to look in my message where I say all I have is a 5V VCC and I can't make a local 3.3V.

The way I read the data sheet, VDD = +5V is allowed.

If you use ON Semi's I know it will work... I designed it ;-)

...Jim Thompson

I was reading the ST Micro one, digikey doesn't stock the ON Semis in Canada. I will look for them and try. Thanks!

It still has ESD protection in that direction. It just has "interesting" disconnect features ;-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

I _did_ notice that - I was keeping it to the point ;)

Cheers

PeteS

Amusing.

I once used the LCX04 (LCX was supposed to be a consortium if I recall properly) as an oscillator. It has (or had) a 'feature' where it could self-oscillate (due to switching speed and ground bounce from my dim recollection of the data sheet), so I used that 'feature' as a real one.

Worked great.

Cheers

PeteS

I think all brands will work the same. Maybe plot IDD versus VDD and see if there's any curvature there BEFORE you commit to production quantities?

...Jim Thompson

Oh it's a hobby thing. It has to work right though.

Production so far has been exactly one. It might be interesting to about 100 people worldwide IMHO.

Nice scope! Haven't seen one of those since I was a kid ;-)

...Jim Thompson

Ahhhh - a _real_ scope where all the controls are visible without any button presses!

:)

Cheers

PeteS

I love the freaking thing. It's older than me. I had the HV transformer rebuilt, so the entire scope should be good for a hundred years at the present usage rate. It's far far better than the low-end POS crap Tektronix is foisting on us these days. When I see a fat trace full of noise, I think my circuit is noisy, not the scope... In my mind's eye, signals are supposed to be razor-thin lines on a CRT with sharp transitions and solid levels, not a festival of noise.

And not to mention all the cool plugins you can get for the thing.

I will say I consider the 'interesting disconnect features' extremely useful, at the least. One might even say it was good engineering :) I can, of course, see those features only as specs, but the spec gives me what I need to know.

So - thanks for a really nice family of devices from an end user who didn't even know you existed at that time ;)

Cheers

PeteS

Thanks!

...Jim Thompson

It's Chartered Semi's 0.6um process, so VDD = +5V is just fine.

...Jim Thompson

Looking at that (ON Semi) datasheet, they are rather vague about supply voltage, in my opinion. The "Maximum Rating" supply voltage is 7V, but the "Recommended Operating Condition" maximum supply voltage is 3.6V - quite a difference.

I like using 74AC series gates to generate fast pulses for use in analogue / RF circuits, but it would be nice to use something a bit faster, provided it could still handle a 6V supply. I wonder what the reliability of the LCX devices really is at, say, 6V.

Do you think it would be reasonable to run LCX devices at 6V in general? Maybe I should try to find a way of buying the NL27WZ series devices - these seem to be at least as fast, and they clearly state that they work at

Chris

Thanks.