Ken Shirriff Takes Us Inside The IC, For Fun

December 27, 2016 by Elliot Williams 13 Comments

[Ken Shirriff] has seen the insides of more integrated circuits than most people have seen bellybuttons. (This is an exaggeration.) But the point is, where we see a crazy jumble of circuitry, [Ken] sees a riddle to be solved, and he’s got a method that guides him through the madness.

In his talk at the 2016 Hackaday SuperConference, [Ken] stepped the audience through a number of famous chips, showing how he approaches them and how you could do the same if you wanted to, or needed to. Reading an IC from a photo is not for the faint of heart, but with a little perseverance, it can give you the keys to the kingdom. We’re stoked that [Ken] shared his methods with us, and gave us some deeper insight into a handful of classic silicon, from the Z80 processor to the 555 timer and LM7805 voltage regulator, and beyond.

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Silicon Wafer Transfer Machine Is Beautifully Expensive

November 30, 2016 by Gerrit Coetzee 31 Comments

There’s nothing more freeing than to be an engineer with no perceptible budget in sight. [BrendaEM] walks us through a teardown of a machine that was designed under just such a lack of constraint. It sat inside of a big box whose job was to take silicon wafers in on one side and spit out integrated circuits on the other.

[BrendaEM] never really divulges how she got her hands on something so expensive that the engineer could specify “tiny optical fiber prisms on the end of a precision sintered metal post” as an interrupt solution for the wafer. However, we’re glad she did.

The machine features lots of things you would expect; pricey ultra precise motors, silky smooth linear motion systems, etcetera. At one point she turns on a gripper movement, the sound of it moving can be adequately described as poetic.

It also gives an unexpected view into how challenging it is to produce the silicon we rely on daily at the ridiculously affordable price we’ve come to expect. Everything from the ceramic plates and jaws that can handle the heat of the silicon right out of the oven to the obvious cleanliness of even this heavily used unit.

It’s a rare look into an expensive world most of us peasants aren’t invited to. Video after the break.

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Building Custom Integrated Circuits

November 29, 2015 by Brian Benchoff 40 Comments

The first integrated circuits weren’t tiny flecks of silicon mounted to metal carriers and embedded in epoxy or ceramic. The first integrated circuits, albeit a looser definition of such, were just a few transistors, resistors, and diodes mashed together in the same package. With this in mind, [Rupert] created his own custom IC. It’s an IR ~~receiver~~ transmitter constructed out of a transistor, resistor, and an LED.

The attentive reader should be asking, “wait, can’t you just buy an IR ~~receiver~~ transmitter?” Yes, yes you can. But that’s not a hack™, and would otherwise be very uninteresting.

[Rupert]’s IC is just three parts, a 2n2222 transistor, a 220Ω resistor and an IR LED. With a good bit of deadbug soldering, these three parts were melded into something that resembled, and had the same pinout of, a Vishay TSOP4838 IR receiver. The epoxy used to encapsulate this integrated circuit is a standard 2-part epoxy and laser printer toner. Once everything is mixed up into a gooey slurry, it’s dripped over the IC producing a blob of an integrated circuit. It’s functionally identical to the standard commercial version, and looks good enough for a really cool project [Rupert]’s been working on.

Thanks [foehammer] for the tip.

A Peek Under The Hood Of The 741 Op-Amp

October 31, 2015 by Dan Maloney 9 Comments

First introduced as an IC back in 1968, but with roots that go back to 1941, the 741 has been tweaked and optimized over the years and is arguably the canonical op-amp. [Ken Shirriff] decided to take a look inside everybody’s favorite op-amp, and ended up with some good-looking photomicrographs and a lot of background on the chip.

Rather than risk the boiling acid method commonly used to decap epoxy-potted ICs, [Ken] wisely chose a TO-99 can format to attack with a hacksaw. With the die laid bare for his microscope, he was able to locate all the major components and show how each is implemented in silicon. Particularly fascinating is the difference between the construction of NPN and PNP transistors, and the concept of “current mirrors” as constant current sources. And he even whipped up a handy interactive chip viewer – click on something in the die image and find out which component it is on the 741 schematic. Very nice.

We’ve seen lots of chip decappings before, including this reveal of TTL and CMOS logic chips. It’s nice to see the guts of the venerable 741 on display, though, and [Ken]’s tour is both a great primer for the newbie and a solid review for the older hands. Don’t miss the little slice of history he included at the end of the post.

Spit Out VGA With Non-Programmable Logic Chips

October 15, 2015 by Bryan Cockfield 53 Comments

It’s not uncommon to bitbang a protocol with a microcontroller in a pinch. I2C is frequently crunched from scratch, same with simple serial protocols, occasionally complex systems like Ethernet, and a whole host of other communication standards. But VGA gets pretty tricky because of the timing requirements, so it’s less common to bitbang. [Sven] completely threw caution to the wind. He didn’t just bitbang VGA on an Arduino, but he went one step further and configured an array of 7400 logic chips to output a VGA signal.

[Sven]’s project is in two parts. In part one, he discusses choosing a resolution and setting up the timing signal. He proceeds to output a simple(-ish) VGA signal that can be displayed on a monitor using a single gate. At that point only a red image was displayed, but getting signal lock from the monitor is a great proof of concept and [Sven] moved on to more intricate display tricks.

With the next iteration of the project [Sven] talks about adding in more circuitry to handle things like frame counting, geometry, and color. The graphics that are displayed were planned out in a simulator first, then used to design the 7400 chip configuration for that particular graphic display. It made us chuckle that [Sven] reports his monitor managed to survive this latest project!

We don’t remember seeing non-programmable integrated circuits used for VGA generation before. But bitbanging the signal on an Arduino or from an SD card slot is a great test of your ability to calculate and implement precise timings with an embedded system. Give it a try!

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How CMOS Works: Some Final Words About CMOS

September 2, 2015 by Bil Herd 18 Comments

Finishing up on the topic of CMOS bus logic I am going to show a couple of families with unique properties that may come in handy one day.

High Voltage Tolerant Family: AHC/AHCT

AHCT w/o high side diode — Note the missing diode to VDD

First up is a CMOS logic family AHC/AHCT that has one of the protection diodes on the input removed. This allows a 5V input voltage to be applied to a device powered by 3.3V so that I don’t have to add a gate just for the translation. Any time I can translate and do it without any additional gate delays I am a happy engineer.

Of course the example above works in a single direction and bidirectional does start to get more complicated. Using a bidirectional buffer such as a 74AHCT245 will work for TTL translation when going from 3.3V back to 5V providing there is a direction control signal present.

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Using A Laser Cutter To Decap ICs

August 24, 2015 by Will Sweatman 26 Comments

The black blob IC is of a particular annoyance to the modern hacker. There is no harm in peeking under the hood to see how the IC works. But when it’s covered in a mountain of seemingly indestructible epoxy, this can be a bit difficult. And such was the case for [Jamie], who had found an old electronic pocket dictionary whose main PC board boasted not one, but two of the black blob ICs.

The lack of traces between the two pushed [Jamie’s] curiosity past the tipping point. He didn’t have access to any nitric acid which is used in the customary chemical decapping process. He did, however, have access to a laser cutter. It turns out that decapping ICs with a laser cutter is not only possible, it’s not that difficult.

100% power at 300mm per seconds on a cheap 40 Watt “eBay” laser cutter is all it takes. Three passes did the trick for [Jamie], but this will be dependent on the thickness of the black blob epoxy. Each case will likely be unique.

Got a laser cutter? Then take a peek at a few black blob ICs and let us know what you find.

Thanks to [ex-parrot] for the tip!