Debouncing....at About 1Mhz

Ah, one is supposed to splice that into your thing. Runs the parts count up even more.

It's not hard to understand. Seems like a lot of work to do such a simple function.

I could say that you have NO CLUE about a number of things, but I won't.

Sure, but sed is dominated by lurkers and critics and farts who haven't done anything original in decades, if ever, and by people who think everything they do is company confidential. That puts a damper on circuit games. Good thing I have a day job where I can have circuit fun... the TI opamps would quit blowing up.

John

Since 17 * 0 = 0, simple algebra proves that 0 / 0 = 17.

John

Have any loose RF? Last time I had a spate of flaming OpAmps it turned out to be a close-by FM station getting into my inputs.

...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 | |

Probably his own self-generated EMI ?:-)

...Jim Thompson

We have junction-rectifying issues all the time. We're about two miles from Sutro Tower, 22 megawatts of TV/FM/HDTV... fuzzes up all the scopes pretty good. But this is a large-signal issue.

I may have mentioned this already. It's a THS3062, a screaming fast, practically unique dual opamp. We based the specs of an arb on its performance. GBW of 400 MHz, slews 7 v/ns, +-15 rails, powerpad SO-8 package. It works fine at low swings, or at +-10 output swing up to 10 MHz or so. Somewhere around 12 MHz, it crashes: it suddenly draws a huge mount of power, gets super hot, the output amplitude drops way down and the output phase reverses (in either inverting or ni hookups!) Reducing the input swing way, way down snaps it out of the mode. It behaves the same way loaded or unloaded, at room temp ambient or flooded with freeze spray. We discovered this when we were experimenting with finding the setup that had minimum THD at high frequencies... turns out that inverting is slightly better than non-inverting at gains circa 4.

Gosh, do you think it's caused by "gate hash"? JF is right, of course: if you don't run signals through parts, problems like this won't happen.

We put in a support request to TI over a month ago. They assigned a case number, but refuse to respond to repeated requests for some sort of answer. I hear that TI has really screwed up the Burr-Brown production line and is in a heap o' trouble.

John

Unlikely; see my other post.

John

Unobtanium obtained...

Now please present us with your "solution" with component names and values and I'll simulate it side-by-side with my design.

Otherwise you will henceforth known as John "BSA" Larkin.

"BSA" == Bull-S*it-Artist ;-)

...Jim Thompson

That's what I hear also.

...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 | |

If you ever say anything funny, we'll let you know.

John

Like you do on Usenet? ;-)

So, Fred, are you going to post your ESR meter design, or ar you still terrified of being shown up as a fool?

I rarely simulate. Design is the reverse of simulation. Design forces the desired results, so why simulate?

The easy way would be to use an AC86 quad xor and an AC74 flipflop. That would actually make the 10 ns prop delay in real life, but not guaranteed over temperature. There are lots of faster parts around, like NC7SZ86 (< 6 ns xor) and flipflops down to 1 ns... 74AUC1G74 would do. Using the tinies would of course require more cans, but they're cheap, and the delay could be a single slower gate. The 1-gate flops doen't have qbar, so you'd need to add an inverter before D if you need straight-up output. Four tiny-logic cans max, if you really need the speed.

So, easy way: 74AC86, 74AC74. The rc tau needs to be somewhat greater than 100 ns and less than 500 ns (100 ns max bounce, 1 MHz rate) so go for tau=220 ns, 330 ohms and 680 pF. This is a little tight on discriminating the bounces from the period, and a serial L would help a lot, as mentioned before; L = 39 uH should be about right. All values are guessed, without mechanical assistance.

If you feel the worst-case AC logic delays are unacceptable, go with the faster parts.

You are being unnecessarily, and inaccurately, offensive. I've designed a couple of hundred million dollars worth of analog/digital/uP/firmware stuff so far, for some of the biggest projects on the planet. My stuff works, and this circuit will work.

Simulate it, if you really need to.

John

Draw it as a schematic, and I will simulate it.

I never even thought of evaluating my design capability in terms of dollars shipped... but pondering, I suspect I'm WAY over your total.

...Jim Thompson

Simulation can only show that an async circuit might work. It can't prove that it always works. Your circuit is sufficiently complex and tangled that it probably has several timing hazards. But it won't meet the 10 ns limit, so it doesn't work to the OP's specs.

The Res Sox didn't like the Yankees, but they played them anyhow. That's the game.

John