6 ms·

555 timer teardown: inside the most popular IC (2016)

108 points by isleofvoid 6y ago

ncmncm 6y ago
To me the biggest surprise was the designer's embarrassment, and the failure of a re-designed successor.
garaetjjte 6y ago
Is there source for 'most popular IC', or this is just another urban legend? I don't know many products that would require timing, but don't have some microcontroller. I would rather bet that eg. 7805 regulator is used much more.
- areoform 6y ago
  Yes! > Since the introduction of the 555 by Signetics in 1972, this integrated circuit has outsold all other IC types by a wide margin, with over 1 billion units sold worldwide in 2003 alone. http://www.semiconductormuseum.com/Transistors/LectureHall/Camenzind/Camenzind_Index.htm http://www.semiconductormuseum.com/Transistors/LectureHall/C... It’s what we used as a starting point in 2005. It's the "Hello World" of electronics, and seemingly a commonality across the world. I love this IC because it is so simple, predictable, and understandable; the perfect jumping off point to learn electronics.
  - panpanna 6y ago
    I would like to challenge that! Consider something like the 741. In fact, let's consider the single opamp IC family against the 555 family (including 556 and the rest). I bet you 55x is nowhere as popular as those.
    - JKCalhoun 6y ago
      Honestly, if it's between the 741 and 555, let's just call it a draw and have a drink together. Shall we?
      - kjs3 6y ago
        Skol!
    - Sanzig 6y ago
      The 741 is obsolete... almost nobody uses it anymore. In terms of a jellybean opamp, I would guess that the LM358 and friends (LM321, LM324, and modernized rail-to-rail CMOS descendants) are quite a bit more popular. The bipolar LM358 family is also pretty much obsolete by modern standards (plenty of nicer rail-to-rail amps available), but you can't beat them on price since they've been second sourced by practically every analog company in the industry.
- exmadscientist 6y ago
  Part of the reason it's historically sold so well is that its particular combination of features is difficult to get economically in other ways. If you want, say, a blinking LED without a microcontroller, it can't really be done without a 555 except at severe penalty in cost, complexity, or both. Any analog solution involving an op-amp, for example, has to deal with the fact that an op-amp is usually more expensive than a 555! (Example: TI's cheapest 555 is the NE555 in TSSOP-8 package at $0.05, and their cheapest op-amp is the LM321LV in SOT23-5 package at $0.04, actually slightly cheaper than I remember last time I went looking for the cheapest op-amp money could buy. But the op-amp will require more supporting components, increasing total cost.) That's not true for voltage regulators: there are many other parts that do what a 7805 does and many ways to build that function, some of which can sometimes end up cheaper. Of course, the previous caveat of "without a microcontroller" is quickly becoming a concern of the past, and, accordingly, the 555 isn't designed in nearly as often as it was even in 2003.
  - panpanna 6y ago
    Well, you do need a number of discrete components in both cases. Sometimes it's just cheaper to use a microcontroller. Specially when they are this cheap: https://www.eevblog.com/forum/blog/eevblog-1132-the-3-cent-microcontroller!/ https://www.eevblog.com/forum/blog/eevblog-1132-the-3-cent-m...
    - JKCalhoun 6y ago
      The 555 had a long run before the micro controllers got as cheap. I think that counts toward it's legacy (and numbers of units sold).
    - sfifs 6y ago
      nowadays it's usually cheaper to use a microcontroller. That actually wasn't true if you go back further than a decade. 555s heydey was when MCs were relatively expensive.
- willis936 6y ago
  You don’t need a 7805 in a switching power supply. You do need a 555. Switching power supplies are in everything.
  - panpanna 6y ago
    You don't _need_ 555 for that. The last one I opened had two lm358 dual opamps but no 555. And nowadays we have dedicated ICs for that kind of things with much better safety and efficiency.
- tenebrisalietum 6y ago
  I was getting the impression this IC was used a lot as a rudimentary analog-to-digital converter, by converting voltages to pretty much PWM.
  - deleted 6y ago
    [deleted]
dang 6y ago
Discussed at the time: https://news.ycombinator.com/item?id=11140981 https://news.ycombinator.com/item?id=11140981
abhgh 6y ago
This was part of an educational kit I played with, as a kid: Chip-Chap [1]. Was too young to understand the "how", but getting things to work by following the manual was an absolute delight! [1] http://hopesprogramkits.tripod.com/products/products_electronicskit.html http://hopesprogramkits.tripod.com/products/products_electro...
jstanley 6y ago
This is an excellent article. I learnt more about IC design/implementation from this article than from any other I have seen. It even has an interactive tool where you can click on a component on either the die shot or the schematic and it shows which parts correspond to each other.
andrewwharton 6y ago
There’s also some fantastic videos explaining the inner workings of the 555 timer (from a practical perspective) in this series on building a clock module for a breadboard computer - https://eater.net/8bit/clock https://eater.net/8bit/clock
timonoko 6y ago
I do remember time when 555 was too expensive and exotic for everyday use. There was standard way to implement same functionality with NANDs using all the gates in SN7400, but cannot find it now in the Interwebbs. Especially when Russians started to make 7400 look-a-likes with 2 millimeter pin spacing.
- kjs3 6y ago
  You could implement some types of multivibrators with NANDs, and oscillators with pretty loose specs, but I'm not sure you could do everything that a 555 could do. The 555 definitely had more precision. But people do forget what could be done with a couple of very simple gates.
JKCalhoun 6y ago
Takes me back... As a hobbyist, I loved Forrest Mim's mini-notebooks you could purchase from Rat Shack: https://archive.org/details/electronics_-_Forrest_Mims-engineers_mini-notebook_555_timer_circuits_radio_sha https://archive.org/details/electronics_-_Forrest_Mims-engin...
- kiddico 6y ago
  This is fantastic. Thanks for the link!
- kjs3 6y ago
  I learned so much from those Mim's books. When I was a EE undergrad I could take the theory and look at how a real engineer did things and often go "oh...I see".
dekhn 6y ago
Recently I was using an arduino to generate a PWM signal to dim a light in response to a potentiometer. I was looking to reduce the complexity of the circuit (removing the unnecessary microprocessor). My first thought was "hmm, I wonder if this is why the 555 exists?"

108 points by isleofvoid 6y ago

To me the biggest surprise was the designer's embarrassment, and the failure of a re-designed successor.

Is there source for 'most popular IC', or this is just another urban legend? I don't know many products that would require timing, but don't have some microcontroller. I would rather bet that eg. 7805 regulator is used much more.

areoform 6y ago
Yes! > Since the introduction of the 555 by Signetics in 1972, this integrated circuit has outsold all other IC types by a wide margin, with over 1 billion units sold worldwide in 2003 alone. http://www.semiconductormuseum.com/Transistors/LectureHall/Camenzind/Camenzind_Index.htm http://www.semiconductormuseum.com/Transistors/LectureHall/C... It’s what we used as a starting point in 2005. It's the "Hello World" of electronics, and seemingly a commonality across the world. I love this IC because it is so simple, predictable, and understandable; the perfect jumping off point to learn electronics.
- panpanna 6y ago
  I would like to challenge that! Consider something like the 741. In fact, let's consider the single opamp IC family against the 555 family (including 556 and the rest). I bet you 55x is nowhere as popular as those.
  - JKCalhoun 6y ago
    Honestly, if it's between the 741 and 555, let's just call it a draw and have a drink together. Shall we?
    - kjs3 6y ago
      Skol!
  - Sanzig 6y ago
    The 741 is obsolete... almost nobody uses it anymore. In terms of a jellybean opamp, I would guess that the LM358 and friends (LM321, LM324, and modernized rail-to-rail CMOS descendants) are quite a bit more popular. The bipolar LM358 family is also pretty much obsolete by modern standards (plenty of nicer rail-to-rail amps available), but you can't beat them on price since they've been second sourced by practically every analog company in the industry.
exmadscientist 6y ago
Part of the reason it's historically sold so well is that its particular combination of features is difficult to get economically in other ways. If you want, say, a blinking LED without a microcontroller, it can't really be done without a 555 except at severe penalty in cost, complexity, or both. Any analog solution involving an op-amp, for example, has to deal with the fact that an op-amp is usually more expensive than a 555! (Example: TI's cheapest 555 is the NE555 in TSSOP-8 package at $0.05, and their cheapest op-amp is the LM321LV in SOT23-5 package at $0.04, actually slightly cheaper than I remember last time I went looking for the cheapest op-amp money could buy. But the op-amp will require more supporting components, increasing total cost.) That's not true for voltage regulators: there are many other parts that do what a 7805 does and many ways to build that function, some of which can sometimes end up cheaper. Of course, the previous caveat of "without a microcontroller" is quickly becoming a concern of the past, and, accordingly, the 555 isn't designed in nearly as often as it was even in 2003.
- panpanna 6y ago
  Well, you do need a number of discrete components in both cases. Sometimes it's just cheaper to use a microcontroller. Specially when they are this cheap: https://www.eevblog.com/forum/blog/eevblog-1132-the-3-cent-microcontroller!/ https://www.eevblog.com/forum/blog/eevblog-1132-the-3-cent-m...
  - JKCalhoun 6y ago
    The 555 had a long run before the micro controllers got as cheap. I think that counts toward it's legacy (and numbers of units sold).
  - sfifs 6y ago
    nowadays it's usually cheaper to use a microcontroller. That actually wasn't true if you go back further than a decade. 555s heydey was when MCs were relatively expensive.
willis936 6y ago
You don’t need a 7805 in a switching power supply. You do need a 555. Switching power supplies are in everything.
- panpanna 6y ago
  You don't _need_ 555 for that. The last one I opened had two lm358 dual opamps but no 555. And nowadays we have dedicated ICs for that kind of things with much better safety and efficiency.
tenebrisalietum 6y ago
I was getting the impression this IC was used a lot as a rudimentary analog-to-digital converter, by converting voltages to pretty much PWM.
- deleted 6y ago
  [deleted]

dang 6y ago

Discussed at the time: https://news.ycombinator.com/item?id=11140981 https://news.ycombinator.com/item?id=11140981

abhgh 6y ago

This was part of an educational kit I played with, as a kid: Chip-Chap [1]. Was too young to understand the "how", but getting things to work by following the manual was an absolute delight! [1] http://hopesprogramkits.tripod.com/products/products_electronicskit.html http://hopesprogramkits.tripod.com/products/products_electro...

jstanley 6y ago

This is an excellent article. I learnt more about IC design/implementation from this article than from any other I have seen. It even has an interactive tool where you can click on a component on either the die shot or the schematic and it shows which parts correspond to each other.

andrewwharton 6y ago

There’s also some fantastic videos explaining the inner workings of the 555 timer (from a practical perspective) in this series on building a clock module for a breadboard computer - https://eater.net/8bit/clock https://eater.net/8bit/clock

timonoko 6y ago

I do remember time when 555 was too expensive and exotic for everyday use. There was standard way to implement same functionality with NANDs using all the gates in SN7400, but cannot find it now in the Interwebbs. Especially when Russians started to make 7400 look-a-likes with 2 millimeter pin spacing.

kjs3 6y ago
You could implement some types of multivibrators with NANDs, and oscillators with pretty loose specs, but I'm not sure you could do everything that a 555 could do. The 555 definitely had more precision. But people do forget what could be done with a couple of very simple gates.

JKCalhoun 6y ago

Takes me back... As a hobbyist, I loved Forrest Mim's mini-notebooks you could purchase from Rat Shack: https://archive.org/details/electronics_-_Forrest_Mims-engineers_mini-notebook_555_timer_circuits_radio_sha https://archive.org/details/electronics_-_Forrest_Mims-engin...

kiddico 6y ago
This is fantastic. Thanks for the link!
kjs3 6y ago
I learned so much from those Mim's books. When I was a EE undergrad I could take the theory and look at how a real engineer did things and often go "oh...I see".

dekhn 6y ago

Recently I was using an arduino to generate a PWM signal to dim a light in response to a potentiometer. I was looking to reduce the complexity of the circuit (removing the unnecessary microprocessor). My first thought was "hmm, I wonder if this is why the 555 exists?"