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.
For almost forty years, integrated circuits have become smaller and smaller. These chips started out with massive transistors in the early 1970s. They shrank to less than 1μm by 1990, and shrank yet again to less than 100nm by the turn of the last century. Now, Imec and Cadence are experimenting with 5nm technology – the smallest technology available for any mass-produced integrated circuit.
The history of microelectronic fabrication over the last decade is a story of failure. Something happened in 2005, and although chips could be designed at ever-smaller technologies, the transition to these smaller manufacturing processes didn’t go as smoothly as in the 70s, 80s, and 90s. Just a few years ago, Intel said 10nm chips would ship by 2015. These chips are nowhere to be found, and even 14nm technology is still catching up to the yields found in 22nm technology. In 2009, Nvidia said their flagship graphics card would be built with a 11nm process. The current Nvidia flagship desktop graphics card is built with 28nm technology. Moore’s law isn’t 18 months anymore.
While Imec and Cadence have completed the tapeout on a 5nm device, it’s just a test chip. Before starting manufacturing on a single process node, Intel and others will tapeout a simple test chip to verify their latest process. This 5nm tapeout will not become a manufactured chip, but it does mean we’ll see more talk about the 5nm process in the future.
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
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.
[Rue Mohr] found a very cheap TFT display on an Arduino shield. The chip for the display was an SPF5408, a chip that isn’t supported by the most common libraries. He eventually got it to work after emailing the seller, getting some libraries, and renaming and moving a bunch of stuff. If you have one of these displays, [Rue] just saved you a bunch of time.
The ancient computers of yesteryear had hardware that’s hard to conceive of today; who would want a synthesizer on a chip when every computer made in the last 15 years has enough horsepower to synthesize sounds in software and output everything with CD quality audio? [Brian Peters] loves these old synth chips and decided to make them all work with a modern microcontroller.
[Brian] connected all these chips up with Teensy 2.0 microcontrollers, and with the right software, was able to control these via MIDI. It’s a great way to listen to chiptunes the way they’re meant to be heard. You can check out some sound samples in the videos below.
It’s totally excellent when a simple concept results in something inspiring and fun. [Rich Decibel]’s Kequencer is a good example, starting off as many projects do: “I had an idea the other day and I couldn’t decide if it was good or not so I just built it to find out.” Be still our hackable hearts!
[Rich] built this sleek little sequencer from scratch and while the design may not seem very novel to begin with–eight square wave oscillators with on/off switches and pitch knobs, played in sequence–but the beauty of it is in the nuances of interaction and the potential for further hacking. From watching the video you can see how the controls can be used in very interesting ways to create and mutate adorable chippy tone patterns. Check it out after the crossfade.
We’ve all known the MSP430s under the Launchpad are designed to be low power, but who wants to bet how long the chip can last on only 20F worth of capacitors? A couple of hours? A day at max? [Kenneth Finnegan] setup a MSP430 with supercaps to find out. To make sure the chip is actually running, [Kenneth] programmed it to count from 0 to 9 over a period of 10 seconds, and then reset. To get it ultra low power, the chip is in sleep mode most of the time, and a raw low current LCD is used to display the output. While [Kenneth] simply checks the chip every few hours to see if it’s still counting, a setup much like the Flash Destroyer, tracking a clock and then storing the current value would get a more exact time of death. Either way, it’s been over 3 weeks…and still counting. Video after the rift.