# Chips that should never go obsolete

#### Dave

Joined Nov 17, 2003
6,970
Take the good old 741, it is a dog compared to the newer devices, it's bandwidth is restricted, it's output will only swing within about 3 volts from each rail and under some conditions, it's output can become non symetrical....
What will universities do if the 741 goes obsolete?

Lecturers, get your course notes and laboratory exercises out and get re-writing

Dave

#### bloguetronica

Joined Apr 27, 2007
1,372
It is all marketing. Semiconductor companies look at who and what they want to compete against. This includes performance, package, and pricing...the 3 P's. (I stole that line from Bill Klein from TI.)

After a part is introduced the market determines the life cycle of a device. If no one wants it, then it slowly wanders into obsolescence.

Keep in mind the Marketing Engineer looks at BIG companies in terms of volume and revenue rather than Joe's Garage or a hobbiest.
Unfortunately (for the hobbysts), the big bucks call the shots!

... Take the good old 741, it is a dog compared to the newer devices, it's bandwidth is restricted, it's output will only swing within about 3 volts from each rail and under some conditions, it's output can become non symetrical.... The 555 should be banned, and every device on the planet should be shot into space (Oh well, I have just lost a few friends!!!).... The old TTL 74 series was great in it's day, but those of you who still use it are not helping the global warming problem...
The 555 timer should be banned? Why?

The TTL74 family has chips that the CMOS series don't have, and it is more reliable. Indeed the 74LS family is still used in microcomputers. Try to build a crystal oscillator using CMOS technology!

#### lightingman

Joined Apr 19, 2007
374
Ah..The oscilator in my home built audio analyser uses a 74HC04 CMOS chip (as a crystal oscilator) at 16MHz.....Don't get me wrong, there is nothing wrong with TTL, as I have said in a previous post.I still have a lighting desk that is totaly TTL (267 chips), it pulls 40 Amps @ 5 volts, fails about twice a year and has eaten three Gould PSU's.....My lighting desk in the lower Theatre (home made) is all CMOS (4000 and 74HC), (738 chips), it pull's 1.9 Amps @ 5 volts), from an LM323K..... I should not say this (but I will) It has failed once in ten years, and that was a 74HC244 gone down on one sub group....I just think (having taught in a school and a college) that it is about time that students were taught with the newer devices, otherwise by the time they leave full time education and enter the big world of technology "it is all obsolete" (just as we have all been moaning about....Daniel.

#### bloguetronica

Joined Apr 27, 2007
1,372
MAX038. Arguably one of the best single-chip analog function generators ever produced.

But, with a zippy microcontroller and a DAC or two...
Excellent chip indeed!

I would rather see a continued supply of TBA820M instead of the LM386, and the XR2206 instead of the ICL8038.
The TBA820M is a class B audio amplifier and has a distortion of 0.8%. The LM386 is a class AB audio amplifier and has a distortion of 0.2%. So, one is needed for less power consumption while the other is required for better quality. In fact, a class AB amplifier has both better sound quality and low power consumption.

#### FredM

Joined Dec 27, 2005
124
The 555 should be banned, and every device on the planet should be shot into space
Why? What do you dislike about the 555 ?
The 555 can be used in many applications other than as a timer or oscillator.. need a small schmit device with programmable upper and lower thresholds? put the upper threshold voltage on the CV, and a potential devider on the trig (2 resistors - Megohms if using CMOS 555) and you have it.. Need a cheap, fast comparator? Use CV as one input, thresh as the other, RC from output to trig, and you have something which for many applications out-performs comparators 5x the price..
I once hated 555's - it was snobbery more than anything else! When I actually examined them and played with them, I realised how wrong I had been!

I would like to see a new part - it would be extremely simple to produce from the exsting 555 mask.. A 555 without the internal resistors, and with all the comparator inputs taken to pins (perhaps also the comparator outputs taken to pins) - this would be superb for window comparisons etc.

#### lightingman

Joined Apr 19, 2007
374
I think my hatred comes form my teaching days, when as I said before, every project had a 555 in it.... This gave students the impression that it and the 741 are the only 2 chips in the world.... I am not blaming the 555 (allthough I would never use one in a new design), I do have 200 in stock (as replacements).... I have never had to use any, so that does show how reliable the are.... O.K. you win, I will slag them off no more....Daniel.

#### bloguetronica

Joined Apr 27, 2007
1,372
...The 555 should be banned, and every device on the planet should be shot into space (Oh well, I have just lost a few friends!!!)...
If we see a cow killed by a falling 555, then we know who to blame!

MAX038. Arguably one of the best single-chip analog function generators ever produced...
About that, I have dissapointing news. I was starting to like the chip, but quoting the initial statement from the MAX038 evaluation kit datasheet:
This product was manufactured for Maxim by an outside wafer foundry
using a process that is no longer available. It is not recommended for
new designs. The data sheet remains available for existing users.
A Maxim replacement or an industry second-source may be available.
Please see the QuickView data sheet for this part or contact technical
support for assistance.
Now I ask: What special processes were employed? Aren't the transistors made the same way? Is that a secret receipt? Or the difference is in the quantity of salt and pepper employed?

#### nxtech

Joined Dec 13, 2007
2
For many of those hard to find parts you can try Rochester Electronics.

#### bbroach

Joined Dec 12, 2007
3
Now I ask: What special processes were employed? Aren't the transistors made the same way? Is that a secret receipt? Or the difference is in the quantity of salt and pepper employed?
Most semiconductor producers use multiple processes, each optimized for different characteristics - noise, speed, power, cost, accuracy, size, complexity, etc. A process is chosen during product definition to suit the characteristics of the application and target market of the device. It's certain that your MAX038 could be fabbed in a different process from the original release, but not without considerable design, evaluation, and characterization costs. This sort of investment - hundreds of thousands of dollars - is never undertaken without a compelling business case. In the long run, obsolete parts will disappear like CRTs, punch cards, and paper tape. If you have favorites that are still available, I suggest you stock up on them. Nokia, Apple, Mot, and many other big OEMs already use mostly uBGA for their portable devices; cost and performance considerations will eventually drive that technology into much of the consumer product space. It won't be that long before you're reminiscing about a time when surface mount chips had leads.

regards, billb....

#### recca02

Joined Apr 2, 2007
1,214
Chips that should never go obsolete
pardon,
do potato chips count?

#### electrocute

Joined Dec 14, 2007
4
I must say 7447 decoder is the best thing you could get. It was one of the earliest IC's that I learnt about in college and i is still in use.

#### rahulan999

Joined Oct 10, 2008
1
I would suggest TEA5711 from Philips. A nice performer! Already obsolete.

#### vetterick

Joined Aug 11, 2008
35
The one that gets me is the electronic systems integrated into larger equipment, things like servo valve amps, PLCs, vacuum gauges, as they age the companies support dwindles, so you have to incorporate another soon-to-be obsolete system.

#### Farlander

Joined Oct 14, 2008
158
I'll add the Max038 to the list. It WAS a 20mHz signal generator, DIP IC, available for around $3... no it's not longer in production, no replacement, and the only company still selling them charges$21 per!