General > General Technical Chat
Why do companies obsolete so many good transistors without substitutes?
coppercone2:
--- Quote from: Someone on September 05, 2022, 12:32:17 am ---
--- Quote from: coppercone2 on September 04, 2022, 11:34:21 pm ---i think you can tweak those numbers to be a little more realistic, its not a billion gate FPGA
sometimes I feel like people start throwing scary numbers around based on some real edge case stuff to try to make a point....
--- End quote ---
Try getting a quote for a fresh batch of obsolete transistors run on a new fab. The figures above are nowhere close to a one off fab of a large ASIC, assuming you'd even take the first batch before they have stabilised the process...
Having been in the meetings with suppliers working through costings for semi-custom diode and transistor parts right up to large ASICs.
Setup and packaging usually dominates the cost of low volumes. Researchers take bare dies from pool services without testing, qualification, or tuning of process control, as the cheapest option:
https://mycmp.fr/price-list/
Which is about the cheapest you can get a low volume set of bare die built for, $1000 per mm2 on a 0.35um BiCMOS fab.
Compared to the retail of the largest production FPGAs:
https://au.mouser.com/c/semiconductors/programmable-logic-ics/fpga-field-programmable-gate-array/?m=Intel&series=Stratix%2010%20GX
$20,000 and up per unit
--- End quote ---
do you need a 0.35um fab for these parts? I guess we might not be thinking of the same chip.
Someone:
--- Quote from: coppercone2 on September 05, 2022, 03:32:06 am ---
--- Quote from: Someone on September 05, 2022, 12:32:17 am ---
--- Quote from: coppercone2 on September 04, 2022, 11:34:21 pm ---i think you can tweak those numbers to be a little more realistic, its not a billion gate FPGA
sometimes I feel like people start throwing scary numbers around based on some real edge case stuff to try to make a point....
--- End quote ---
Try getting a quote for a fresh batch of obsolete transistors run on a new fab. The figures above are nowhere close to a one off fab of a large ASIC, assuming you'd even take the first batch before they have stabilised the process...
Having been in the meetings with suppliers working through costings for semi-custom diode and transistor parts right up to large ASICs.
Setup and packaging usually dominates the cost of low volumes. Researchers take bare dies from pool services without testing, qualification, or tuning of process control, as the cheapest option:
https://mycmp.fr/price-list/
Which is about the cheapest you can get a low volume set of bare die built for, $1000 per mm2 on a 0.35um BiCMOS fab.
Compared to the retail of the largest production FPGAs:
https://au.mouser.com/c/semiconductors/programmable-logic-ics/fpga-field-programmable-gate-array/?m=Intel&series=Stratix%2010%20GX
$20,000 and up per unit
--- End quote ---
do you need a 0.35um fab for these parts? I guess we might not be thinking of the same chip.
--- End quote ---
Okay, so you could link some pricing for other cheaper processes? The 0.35um BiCMOS is not an additional constraint/limitation I added, but just the datapoint for those who aren't going to go through and read the detail in the link (and a reasonable choice for making a discrete RF transistor). Find any cheaper low volume fab option, that example above is minimum order $5000-$6000
GlennSprigg:
I guess, just like 'Medicines' on the market. We would like to think they just want to do 'nice things', but the reality is that
they are a Business that has to make money, for them & shareholders. Sometimes, certain 'Transistors' etc, are not always
used as intended/designed too. So can be hard to find a replacement. At the same time, I'm sure that many are 'specified',
where the system will work perfectly well with some 'replacement'. Sometimes, the field is 'specialized', and using old technology.
One that comes to mind, is old TTL circuits as opposed to CMOS. Ok, TTL didn't suffer from 'spikes/static', but drew a lot of power
and was locked in to 5v. CMOS suffers from spikes etc, but uses very little power, and works over 3 - 15 v. The old stuff is out!
Try an tell my Chemist(s) where my old Meds are gone, and why?? 8)
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