that PLL again

Nov 28, 2014 187 Replies

Sure.

Not for an IC designs, which is what Jim and I do.

To Fab an IC is going to take maybe 12 weeks even after the layout is submitted. The cost and time makes design by physical construction, essentially, impossible.

IC design involves choosing specific individual sizes for transistors and resistors, e.g. for matching, 1/f noise,speed. It is not practical to have "kit parts" of all the options needed. Test building 10,000 transistor analog circuits is just not realistic.

IC design is not like that. It's a fact that when I design large transistor count analog IC chips, they come back and, essentially, work correctly right out of the box. My latest has only trivial blemishes.

A one off success is just that, something tweaked that in most cases won't work in production of millions of parts. Simulation is the only way to reliably design for component variations. An IC design typically involves running > 10,000s of simulations to verify that over all process corners , supplies and temperatures that the design will still work. Waiting for a batch of customers after release, as process verification does not keep customers happy.

Kevin Aylward

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- SuperSpice

I do many designs at once. I general run the longer stuff on Cadence, and do lots of minor stuff in SuperSpice in parallel.

Kevin Aylward

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- SuperSpice

Jim Thomps>>

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So many lurkers here don't understand designing for production. ...Jim Thompson

| James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.

Well, we get the California Organic ones at the store down the hill.

When I was a kid, in Louisiana, I used to shoot them out of the trees with a .22.

John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com

San Saba is about a hour drive from me. The self proclaimed "Pecan Capital of the World". They do ship millions of pounds each year. Back in the '70s the feds were pushing the "nut program" and everyone and their brother was going to get rich off nut orchards. The area around here was a hot bed of activity, soil, climate is good. Many of the housing developments are in former pecan orchards. It's really obvious with a Google Earth view. Most people give them away, you just come pick them up. Most common is the Texas Paper Shell, easy to crack.

We will have to try a batch with the light syrup.

Chisolm Republic of Texas

The ones we bought at the fru-fru little grocery down the hill were shelled halves, $18 a pound, and labeled GLUTEN FREE . Safeway was stripped by the time we got there, looking like the Vikings had just left.

This morning I made, on demand, my Pancake Descending a Staircase [1]. Pecans, blueberries, banana slices, part raw, part burnt.

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Some things, like pecans and bananas and broccoli, are good scorched.

[1] breakfast food version of

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John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com

Extremely complicated? Where?

My little Spice sim was fun and helped me think about some issues. It will look nice in the customer design review, too, a nice graphical illustration of the loop acquisition and tracking.

Adding noise would be an interesting next step, if I have the time and energy to do that.

10 lines of C? Post it!

All we buy now is 1% resistors. They are so cheap it doesn't matter. Sometimes we use the 0.1% or 0.05% Susumu thinfilms, too.

John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com

Yum, I made french toast this morning, Ma wanted fried bananas and walnuts on hers, (I made mine the same.) melted butter, maple syrup, bacon on the side and coffee. Back to work tomorrow so no time for a nice breakfast.

George H.

Pity they probably won't have anyone there who understands plls, and who can truly understand what you have done.

On a sunny day (Sun, 30 Nov 2014 16:02:17 -0800) it happened John Larkin wrote in :

You sure make it sound that way!

So far I have posted most of the code, for sure once this works I will post it. You can also download the open source AD kernel driver ( AD4350.c AD4350.h ), google, and you have it, or start here:

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written in a different way as I use the PC parport for this, that one uses the SPI. The chip is not actually SPI, it uses data, clock, and some latch enable to strobe the data into the internal registers, 6 32 bit registers. No return data pin (to see if it acceped that data like SPI can, could have been easily added, they have a multiplexed output that allows you select and see various counters etc). Did you read the ADF4350 datasheet and see the evaluation board circuit diagram?

That is dogma, trillions of teefees have been sold that worked very will without slimulations. Talk about mass production Jim!!! The variations in tubes were much more than 20 % some times, and it still worked.

Sure, I have some 1% from ebay (strange values BTW), and a lot of 5%.

I can make things work with 20% too. I also have some nice 25 turn Bourns trimpots really cheap from abay, recommended...

Am 01.12.2014 um 11:19 schrieb Jan Panteltje:

"Every trimpot proves your ignorance"

My first boss, and he was right. It always worked without.

Gerhard

On a sunny day (Mon, 01 Dec 2014 11:56:14 +0100) it happened Gerhard Hoffmann wrote in :

Nope, maybe for thousands it costs money, any trimming or adjustment. But for equipment that just a few are made (say

Not all trimpots are stupid, just as not all managers have pointy hair.

He said that like it was a bad thing, whereas due to component variations, some level of ignorance is often inevitable. This is especially true in mixed-technology systems, where you can't always just specify 0.1% components.

Even then, a lot of the time a bit of self-calibration code can make trimpots or other manual tweaking unnecessary, but not always. For instance, tuning a diode laser to a given frequency requires temperature control, but there's a lot of unit-to-unit variation. It usually makes a lot more sense to measure the frequency in the lab, and adjust the set point to get it where you want it. Otherwise you'd have to put an interferometer in every box to do the measurement.

I'm mostly agnostic about trimpots vs. EEPOTs or other ways of storing the customized setpoints, because that's mostly an issue of convenience and prevailing fashion. Just because you're ignorant doesn't make you stupid. ;)

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net

Not a sentiment I share. I design them out whenever I can, but there are situations where they can make sense.

There is always the risk that some idiot will fiddle with them, and a blob of sealing wax can be a good idea if there are graduate students in the vicinity.

Bill Sloman, Sydney

The other thing about trimpots is that they can have really low capacitance, so you can use them in places where other sorts of adjustments would be difficult, e.g. matching gains on two high frequency signal paths.

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net

Yeah, if anyone here truly understood this, they would have pointed out the big mistake that I made, and just thought of.

John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com

My youngsters hate trimpots. They would rather use a dpot, and a uP, and some embedded code, and a USB cable, and a Windows program, to trim a gain. I use a screwdriver.

These work fine at 1 GHz,

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but you'll need the special tiny ceramic screwdriver to tweak them properly.

John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com

Joerg, please tell us about what you ordered.

Thanks, - Win

There's more than one mistake.

But it's pointless to waste time trying to tell you.

That is a generalisation...

Kevin Aylward

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- SuperSpice

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