Maxim IC frustration - hard to find components

As a former Maxim employee, I did my best to stay out of this thread. However, the MAX7219 was one of the more "entertaining" parts I designed. [As an analog IC designer, doing digital is nice for a change.] I had to fight the powers that be to design it using VLSI's process, rather than our fab. The chip would have been huge in 3um. Not only did the smaller channel length fets help, but the double metal sealed the deal. I designed the power fets in both processes and it just wasn't a contest. [If you look at the die, the power fets are build around the bonding pad for the best resistance to electromigration problems.] The issue was given the usual 3 passes it task to get a chip into production, that would cost a fortune at VLSI. Still, I won on the merits of doing it in the finer geometry process. The chip went through what was nearly a full circuit spice simulation on IIRC a 90Mhz PC. We had a room in what was the old Tech Fed Credit Union building that had a few PCs in it for either long runs or just to be in a place not to be disturbed. The serial I/O plus dual port ram was one simulation, then the rest of the chip was the other simulation. I took at least two weeks of simulation.

The chip worked on the first pass, including passing burn-in, latch-up and ESD. When Maxim got its one 1um process (1.2um I think), I tweaked the chip for that process. It was run along with test patterns to get the bugs out of the process. There is nothing like having a real chip to play with when a process is being developed.

There are a few issues with the part. One is the burn-in test mode. [The part is burned in with all digit drivers being exercise, i.e. dynamic burn-in.] It is mentioned twice in the datasheet, but many people don't read the datasheet carefully. Once you are in burn-in mode, all the leds stay on no matter what you do. I ended up talking to a customer from Australia that spent weeks with apps trying to figure out what was going on with this part as he would get in that mode. Finally the call got bumped up to me, to which I replied "No big deal, you got the part in the burn-in test mode, as shown on page blah blah blah." He was a bit irate as nobody in apps pointed that out. When the datasheet was being written, I tried to get a special section in it warning about the test mode, but that was deemed to be too alarming. You don't want to scare off the customers. The other argument I lost was the designation of "serially interfaced" rather than "serial interface.' Which do you want, good gramar or common engineering speak?

There is also something funky in the serial interface. I don't remember the problem exactly, but it has to do with the chip select not gating the load pulse or something like that. I don't have the datasheet in front of me so I can't recall the exact problem. I noticed the chip is being sold in surface mount, so it was tweaked by someone after I left. Maybe that problem is fixed.

Almost everything I wanted to put in the chip got approved. The exception was the ability to set the intensity of every digit individually. I wanted to use it so that a cursor (blinking digit or different brightness) could be implemented. I did an app note later on how to add a cursor with external parts.

One nice thing about the part is the use of current mirrors to set the peak current via the external resistor. Current feeding the LEDs makes the displays have uniform intensity even if the LEDs don't match well. The analog control was also used in some military apps where NV goggles were used. [The military apps did a combination of PWM and analog to set the intensity.]

I guess you like Japanese food. I do, too :-)

[ ... story how MAX7219 was born ...]

Thanks for sharing this story. It is nice to have direct feedback here from companies, even if it's former employees. I don't know why you left but Maxim could be a great company if they got their hands around some serious logistics problems I (and others) had to face. Maybe they should design less chips or use 3rd party fabs more. The chips I saw were mostly video and PWM related. I really admired their design and the nifty functions they offered. But they were all single-sourced and because my clients could not take delivery of any substantial quantity in time I ended up having to design them all out. The only Maxim part I ever left in a design was a Dallas digital potmeter. Because, to my surprise, it was available.

Jack Gifford doesn't like three things: Phd, MBA, and product engineers. The lack of product engineering is the reason for poor delivery. When I was there, we orphaned only one chip. It was an offline switcher of sorts that was capacitor coupled. Not only did it have problems, but it was deemed kind of dangerous.

Hi,

Just thought I'd add a little vitriol (looks like we have a good amount going already!).

In article ,

I nominate ST, Philips.

A few years ago I was thinking about using a Philips uC and checked out their site. They had some crap "parametric" search that failed to work. After hours, I finally found the part I wanted. I figured I should pass some feedback to Philips and I wrote them (nicely) saying how much difficulty I had finding the part I wanted. I got a very rude response from Philips (a female if it makes a difference) tell me "I had no issues finding this part". Yeah, if you know what part you want...

On the US front I say National and Intersil have crap websites. Intersil blows for needing so much Flash...WTH? Are they pandering to low attention span 5-year olds?

John.

Just curious: What does he like? If you can't generate enough product to fill orders a company isn't going to thrive. When I ran the division of a company my first priority at all times was to make sure that production was humming.

I sprung for a radio to keep them happy.

Best regards, Spehro Pefhany

Hello Spehro,

One of our guys said "If I go in there and hear Mr.Bojangles one more time I am going to scream". But that's nothing compared to the schmaltzy stuff they listened to in a German production facility. It could make your toe nails curl.

I think we all (well, most) agree Maxim has some great parts, and I enjoyed the story above, but great parts is not the issue, as the thread has noted heavily ;)

Cheers

PeteS

The machine shop I occasionally worked at in college had a bunch of old(er) machinists who preferred to listen to country music and Paul Harvey... really drove some of the highly-liberal college students nuts. :-)

Hello Joel,

Ah, my kind of tunes. I like Country. Not the modern stuff but old Americana. And Blues.

Eeeeewwwww

That's almost as bad as Barry Manilow greatest hits for 'animated production'

Cheers

PeteS

I remember listening to Paul Harvey - I was always amused that his tone and pitch did _not_ change during his commercials ;)

Cheers

PeteS

Hello,

My name is Rebecca and I supervise Maxim Dallas Direct, a sales channel from which customers are able to order Maxim & Dallas parts directly. One of the main reasons Maxim Dallas Direct was created was to allow customers to receive pricing and availability from a Maxim Dallas specialist with a vested interest in getting the customer what they want, when they want it. I'm sorry you were led to believe these parts had long lead times, but here is what we currently have available. All units are in stock in the Philippines, 4 days transit directly to you.

DS2745U+ 40 units $1.65 each MAX1724EZK27+ 40 units $2.11 each MAX1522EUT+ 40 units $1.61 each (quote#A1381106) MAX1555EZK+ 40 units $1.34 each

We are moving towards lead free (noted by the + at the end of the part number) so that I what I am quoting (if you have any questions regarding lead free there is a notification on our website at

If any of these are not the exact package type you need or if you would like to order free samples please let me know. For future reference please feel free to call us directly at 888.629.4642 and any sales person can assist you. If you would like to place an order please email snipped-for-privacy@maximhq.com or fax to 800.992.1884. Thank you and I apologize for your frustration.

Sincerely,

Rebecca Graves

snipped-for-privacy@yahoo.com wrote:

Hello Rebecca,

Thanks for posting here in the group. Does that direct channel also work for customer with large quantity needs? That's where my clients had the most problems. They could buy a few dozen but when they wanted some reels they pulled a blank (and I had to design the Maxim parts out). Mostly these were PWM and video chips.

A suggestion to upper management at Maxim: Keep track of all inquiries, especially those where customers could not be satisfied with the desired quantities and have walked away.

Ah, you like both kinds of music; Country _and_ Western.

I still listen to him on occasion. His "The Rest of the Story", is often interesting. the commercials start with even numbered pages. ;-)

Hi, Rebecca,

It's getting to be conventional wisdom among EEs that one should avoid designing Maxim parts into products. It doesn't help that pinouts are deliberately made non-standard.

I've been personally burned four or five times. At this instant, we can't ship over a million dollars worth of product because Maxim has slipped their promised delivery date on MAX5205's. Do you know where I can score a couple of hundred?

I've been having friends and family request samples, which are available. Every 8 dacs we can scrounge, we can ship a $54,000 laser modulator.

John

I'm curious which parts you think have deliberate non-standard pinouts. I can tell you in the decade I worked there, this was never an issue. Pinouts are carefully chosen to minimize noise, ease PCB layout, etc. To keep costs down, Maxim doesn't make a die per each package type (in general), so pinouts are designed to work across many package types. [Back lap specs change from package to package, so often wafers get allocated to one particular package at the expense of another, which in turn causes shortages in a particular package type.]

At no company did I ever deliberately make pinouts to be non-standard. If anything, if a part exists already with defined pinouts, you make it a point to use THOSE pinouts in order to steal the sockets with your hopefully superior product.

For one chip I did at a company I better not mention, a customer leaked us a datasheet of a competitors part. We actually changed our part to match their pinouts since our part was still in design. They had an interesting feature that I added as well. As luck would have it, our part came out before their part, but with the competitors pinouts and features. While we were doing high fives, I suspect somebody at the competition was pounding their fist on the conference table.

WSM AM Radio 650 KHZ in Nashville has several slots during the week were they only play early country and western music. You can listen online at

You can also hear the "Grand Ole Opry" live and in stereo on Friday and Saturday evenings. I have it on almost around the clock. You can listen for four hours before you are dropped, but all you have to do is click on the "Click here to keep listening to WSM" button to start the stream again.