Basic IC's

[mark_3094]

Here are my basic notes on IC's.
I have written the first document on 'What is an IC', and the other four are written to explain how some specific IC's work, such as the famous 555 timer.

Please let me know what you think.
I'm after accuracy, misleading information, missing information, etc

Thanks everyone!

 

[Mikebits]

What, are you trying to write a book?

 

[mark_3094]

I'm trying to write notes as I'm going. I'm writing them in a way to be able to 'teach' others, which helps me to learn.
But I'm also hoping that my notes will be of some use to someone else in future, once I have compiled them.
So, yes, in a way I am writing a book, or at least an introduction guide.

Trying to 'pay it forward' as your signature says

 

[Gayan Soyza]

Put the IC description first & explain the pin arrangement after.

Sam electronics has his nice manual collection.You can get more data from that.

**broken link removed**

 

[colin55]

Revisions:

 

[Mikebits]

I'm trying to write notes as I'm going. I'm writing them in a way to be able to 'teach' others, which helps me to learn.
But I'm also hoping that my notes will be of some use to someone else in future, once I have compiled them.
So, yes, in a way I am writing a book, or at least an introduction guide.

Trying to 'pay it forward' as your signature says

Fair enough.

I suspect the 4000 series logic family is reaching its end of life and soon to be obsolete, with that said, you may not want to write about this logic family, rather use newer logic families with same functions.

 

[mark_3094]

Is the newer logic family the 7000 series?

 

[mark_3094]

Quick question;
Why are 555 timers not used for digital circuits? What is the correct alternative?

 

[Mikebits]

Is the newer logic family the 7000 series?

Have a look here. Look at the 1st graph.
Glue Logic IC Family Selection Guide


This is also worth a read.
Logic family - Wikipedia, the free encyclopedia

 

[mark_3094]

Here is my revised 555 timer doc.

 

[mark_3094]

I've been searching around, but I can't find the pin that makes the 4017 count down...
Which one is it???

 

[ericgibbs]

I've been searching around, but I can't find the pin that makes the 4017 count down...
Which one is it???

Mark,
Because there isnt one, it only counts UP.

EDIT:
555 draft

Quick question;
Why are 555 timers not used for digital circuits? What is the correct alternative?

They are used in digital circuits.!

 

[allegro]

Here are my basic notes on IC's.
I have written the first document on 'What is an IC', and the other four are written to explain how some specific IC's work, such as the famous 555 timer.

Please let me know what you think.
I'm after accuracy, misleading information, missing information, etc

Thanks everyone!

I think you have a mistake, an input pin's voltage doesnt have to be 0V in order to sink current.
Couldn't it be 1L and still sink current?

 

[mark_3094]

Sorry, I thought I read somewhere that it was an up/down counter...

In the revision of the 555 doc Colin55 mentioned that 555's aren't good with digital circuits... I was just wondering why.

 

[colin55]

You don't find "professional engineers" designing with 555's. 555's are a very simple chip with lots of problems and there are lots of chips that will take the place of a 555.
Firstly a 555 will not go higher than about 300kHz. It consumes at least 10mA and is almost useless on 5v as the output will only rise to about 3v and fall to about 2v.
But most of all it’s a poorly designed oscillator. It uses a "crowbar" arrangement to discharge a capacitor.

It's a sort of "rough and ready" chip for simple designs such as oscillators for automotive work.
For battery designs you can get a chip that takes less than 0.1mA compared to 10mA for a 555.
It also produces a lot of noise on the power rail that can be reduced by capacitors, but why incur extra expense.

I’m just saying you don’t see it in professional designs ( I am talking about large, complex designs) and when you can buy 6 CMOS oscillators in one chip for $1.00, why waste time with a 555.

Don’t get me wrong. It’s a wonderful chip and it only costs 17 cents. But if you designed a circuit for me around a 555, you would be shown the door.
None of my professional staff would use one either and they all come for different backgrounds.

I am talking about a digital circuit with a number of chips (logic chips).
For a simple, robust design where current consumption is not a problem, you can use a 555.

 

[mark_3094]

For pin 2, I have 'This will turn the chip on if the voltage is less than 1/3 of Vcc'. Is that wrong?

 

[colin55]

More revision to 555:


You should really state that 555 is a TTL device and 7555 is the CMOS version. There is no CMOS 555.

 

[Mikebits]

More revision to 555:


You should really state that 555 is a TTL device and 7555 is the CMOS version. There is no CMOS 555.

What about the LMC555?
https://www.electro-tech-online.com/custompdfs/2009/03/LMC555.pdf

 

[colin55]

The LMC555 is not a 555. It is a completely different chip that just happens to behave exactly like a 555. I am talking about a 555. A 555 is just a TTL chip.

It is exactly the same as all the TTL 7400 series. None of the 7400 are CMOS. But a 74cxxxx is a CMOS version of a TTL chip and performs an almost identical function but possibly not to the same high frequency of the TTL version, but consumes less current.


The original poster had a heading on this article: "555" This means just the 555 TTL timer chip.

He should have written "555 TTL timer and 7555 CMOS Timer."

 

[ericgibbs]

What about the LMC555?
https://www.electro-tech-online.com/custompdfs/2009/03/LMC555-1.pdf

Not forgetting the
TLC555
TS555CN