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Analog Devices AD1139
- th0ma5 5y agoReally nice tear down. These digital synthesizers have been really great for breathing new life into amateur radio and digital single generation.
- aix1 5y agoBeautiful pics. I wonder why, in a few places, there are pairs of bonding wires connecting the same pads.
- FPGAhacker 5y agoI’m speculating but when I’ve seen it in the past it was for handling higher current. In this case I’m wondering if it’s used to maintain better control of the voltage gradient on a pad.
- ejiblabahaba 5y agoSometimes it's to handle higher currents, other times it's to reduce the bond wire inductance and improve the high-frequency response. For power pins it can be both. Especially for a multi-chip module with some digital circuitry, there's potential for high-frequency digital transients that need nearby decoupling capacitors through low-inductance loops, or the transistor switching noise can pollute other copackaged circuit supplies; amplifiers also benefit from lower inductance on the supply lines since it stabilizes the frequency response at higher offsets beyond the loop bandwidth of any integrated supply regulation, current sources, bandgap references etc. So you're essentially correct, it's about voltage gradients, but probably at higher frequency.
- magicalhippo 5y ago> Beautiful pics. He uses[1] Helicon Focus[2] for focus stacking. A lot of these die shots are pieces of art, and also quite interesting. I especially like the LTZ1000 voltage reference[3] or the Thyracont Inclinos[4] which is an accelerometer without moving parts. A lot of the MEMS dies are also very interesting, because of their moving parts, like this[5] ADXL213. [1]: https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3546374/#msg3546374 https://www.eevblog.com/forum/projects/transistors-die-pictu... [2]: https://www.heliconsoft.com/heliconsoft-products/helicon-focus/ https://www.heliconsoft.com/heliconsoft-products/helicon-foc... [3]: https://www.richis-lab.de/REF03.htm https://www.richis-lab.de/REF03.htm [4]: https://www.richis-lab.de/MEMS_04.htm https://www.richis-lab.de/MEMS_04.htm [5]: https://www.richis-lab.de/ADXL213.htm https://www.richis-lab.de/ADXL213.htm
- sydthrowaway 5y agoAD make some good chips. Along with Realtek they kickstarted the SDR revolution. No hype or trite SaaS products here, just good old school engineering. If only they paid like they sold ads.
- artemonster 5y agoit annoys me to an unbelievable levels that all that CRUD SaaS crap is called "tech" nowadays.
- loxias 5y agoBut think of the epic problems they needed to solve to get the protocol implemented using websockets in javascript so it can run in the iframe on the mobile browsers! Such engineering prowess! </sarcastic>
- auxym 5y agoWe're veering pretty far off-topic, but, as a mechanical engineer working in research, yes. Develop a new ceramic material for advanced turbofan engines? Not tech. Web front end? Oh yeah, tech.
- omneity 5y agoIsn’t that just called engineering?
- jhgb 5y agoNo, technology is the application of science and other knowledge to achieve practical goals. It started with agriculture, metallurgy, etc. thousands of years ago.
- omneity 5y agoYour answer is very condescending. I am referring to startup industry terms. Tech for most web related activities, engineering or Deep tech for the others mentioned in this thread. Excerpt from the wiki[0]: > Deep (or hard) tech is a classification of an organization, or more typically a startup company, with the expressed objective of providing technology solutions based on substantial scientific or engineering challenges. [0]: https://en.wikipedia.org/wiki/Deep_tech https://en.wikipedia.org/wiki/Deep_tech
- sneeeeeed 5y agoGreat tear down but I’m more of a TDA1541 man myself.
- desdiv 5y agoSome context: >The AD1139 is the first DAC offering 18-bit resolution (1 part in 262,1441) and true 18-bit accuracy in a component size hybrid package. A proprietary bit switching technique provides high accuracy, speed and stability without compromising small size or low cost.[0] Just curious, I looked up the price: Digikey, 1 unit: $2,449.80 USD [1] Analog Devices, 100-499 units: $1706.58 USD Analog Devices, 1000+ units: $1706.58 USD [0]: https://www.analog.com/en/products/ad1139.html https://www.analog.com/en/products/ad1139.html [1]: https://www.digikey.com/en/products/detail/analog-devices-inc/AD1139J/616867 https://www.digikey.com/en/products/detail/analog-devices-in...
- metafex 5y agothat's interesting, ADI doesn't even list it anymore on their website but it's marked as still active. i guess it's still used in some test&measurement equipment.
- the__alchemist 5y agoThere seems to be no price cap on AD components! Solid stuff at a range of prices. It's sometimes tough to tell what makes the super-expensive ones different. Might be a little extra precision (etc) that's justified in niche cases.
- jeffbee 5y agoIsn't is just market segmentation? The only people who need this thing are building test equipment that costs big money regardless.
- coretx 5y agoI'd love to have one in my radio
- GeorgeTirebiter 5y agoHow could one use an 18-bit D/A in a radio? (an 18-bit A/D is a different story).
- Pixelbrick 5y agoGreat write up - thanks OP, I'd not seen a hybrid torn down like that before.
- londons_explore 5y agoWhen was this released?
- Renaud 5y agoLooks like it's as least as old as the 90s. Found a picture of one sporting a 9943 date code. The one in the article is from 2002. Analog still lists them in production!
- tpmx 5y agoThe datasheet PDF doesn't contain an obvious date, but it's is clearly scanned and it also contains a sample circuit for connecting it to an IBM PC via the ISA bus. So somewhere between 1981 and 1995, perhaps. There's a document id on the last page that may indicate it's from 89. https://www.analog.com/media/en/technical-documentation/data-sheets/AD1139.pdf https://www.analog.com/media/en/technical-documentation/data...
- loxias 5y agoReally stupid question: I thought I've used a 24bit DAC, on some high end sound equipment. Why is this special/noteworthy?
- LeoPanthera 5y agoI believe this chip was first available in 1989. It's old technology.
- magicalhippo 5y agoNot all DACs are equal. Even average soundcards sport a 24bit DAC. However they're designed for a dynamic output so tend to have quite crap DC precision. What matters to a soundcard is producing a precise waveform, not a precise DC voltage. This part is designed for DC level setting, ie a programmable reference voltage. Typically it won't change that often (compared to a soundcard), but it needs to be precise. For example, compare the AD5791[1], a 20-bit DAC with 1LSB DC accuracy costing $40 in 1000 qty, to a 24bit audio DAC like the AD1955[2] costing about $7. The datasheet for the audio DAC doesn't even specify the DC precision, only a 6% gain error from the output buffer. [1]: https://www.analog.com/en/products/ad5791.html https://www.analog.com/en/products/ad5791.html [2]: https://www.analog.com/en/products/ad1955.html https://www.analog.com/en/products/ad1955.html
- londons_explore 5y agoAre the traces gold plated?
- jjoonathan 5y agoYep. This hybrid was probably manufactured in open air, so they would want gold plating to prevent it from oxidizing while heated during wirebonding / die attach.