s used, that was the old way
could handle that.
I do that where practical. It means parts are cheaper when you can use any old jellybean, mix & match whatever's cheap or in stock. Assemblers can eve n sometimes use batches of unknown house-marked parts if various criteria a re met. But of course such an approach requires very conservative ratings & is too inefficient for semi-demanding tasks. And obviously it's no go for many products & most companies.
NT
It's also useful as a technique for designing rad-hard circuitry. Radiation kills electronics by causing certain parameters to drift as a function of dose. When a critical parameter drifts far enough, your gadget stops working.
Old IC processes yielded poorly controlled device parameters, and designs were dimensioned to accommodate that. Such designs were often also pretty rad-hard. Modern IC processes control device parameters much better, and circuit designs have evolved to expect narrower tolerances. They still drift under irradiation. As a result, modern ICs often have very poor radiation hardness.
It matters to me.
Jeroen Belleman
I don't think I have ever seen any of that. What I believe in is progress, and getting rid of the horrible mess of wires and providers and protocols that we have now.
Sure. If the signal is weak in your basement, buy a repeater at Safeway for $10.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
I bet you have a fairly fast edge driving them though, you're not relying on the Schmitts to speed up a slow edge.
Clifford Heath.
For rad. hard, big old fat leaky* transistors are better. (?)
George H.
*since reading something about adjective order in English, I'm always astounded, when I try and scramble the order it never sounds right.Am 21.09.2018 um 22:06 schrieb George Herold:
A temp-compensated VBE multiplier.
Cheers, Gerhard
It's really not a good idea to put current into ESD diodes - it ends up flowing into the substrate and can come out anywhere, and while that's happening you can't have any confidence about logic states anywhere else on the same substrate.
Been there, been caught by that.
-- Bill Sloman, Sydney
I'm sure the hackers can't wait.
-- Bill Sloman, Sydney
upsidedown wrote
Yes, but I myself will only need 50 Mbps... nice if I can take it with me as a small wireless router access point, say on boat or camping. They have those 'mifi' 4G things these days with 10 hours or so battery life. All of Europe is covered by the same SIM card subscription / cost these days.
30 Euro a month for 10GB a month.George Herold wrote
I think it is the 1.2 V bandgap reference, the good old TL431 uses that, and 2 resistors, to make a parallel stabilizer (= zener). It is a bit more stable than a Vbe multiplier with one transistor and 2 resistors.
to 1k
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d base PNP.
th the NPN:
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?lowing into the substrate and can come out anywhere, and while that's happe ning you can't have any confidence about logic states anywhere else on the same substrate.
plenty of logic, mcus, fpga that specify safe input as either max voltage or max current
Widlar diode is another name...
piglet
Some older logic, especially 4000 A-series, would latch up and fry if you forward-biased the ESD diodes just a little. HC parts are usually specified for 50 mA into the diodes, and I've never seen one latch up.
It's fairly common these days for data sheets to explain how much current you can dump into the ESD diodes of powered-up chips. Opamps often let you dump a lot. See AoE3 p 361.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
Thanks, I've used these as voltage references, but never thought about using them as voltage 'droppers'.
George H.
The bandgap isn't biased right if it only has a CMOS input on the anode end. So, the transistor is complete with two resistors, +5, -5V, and no other power, but the bandgap solution will require a milliamp or so of current, and long LOW duration means it'd benefit from a third (-12V) power source.
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te:
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get.
er,
nded base PNP.
with the NPN:
Gor going 'on',
ate?
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p flowing into the substrate and can come out anywhere, and while that's ha ppening you can't have any confidence about logic states anywhere else on t he same substrate.
eLatching up in't the problem I was talking about (though it's one more odd thing the chip can do). The logic states on the chip can stop conforming to the input-to-output relationships specified in the data sheet. That's a mo re subtle problem and is usually non-destructive, but can be equally fatal to the proper operation of a circuit.
They tend to be less forth-coming about the way the chip behaviour changes while you are dumping that current into the ESD diodes.
The business of stopping a op amp blowing up is less subtle than having it behave correctly while the ESD diodes are carrying current. Win Hill's flat tery didn't go into that.
-- Bill Sloman, Sydney
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