Yes, my error, realized that after pressing send, you use a grounded base PNP. Just to talk myself out of it, this works just as good or better with the NPN:
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The zener is optional, for a -5V supply you do not need it.
It is 'better' as the negative edge speed is set by the transistor going 'on', not by the collector resistor as in your circuit. That is if he needs that ..
Authorized distributors sell real parts. Small shops and ebay can sell you anything, and a long-term supply isn't assured. Distributors send us EOL notices so we can plan ahead.
There are entire towns in China that are in the fake components business.
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John Larkin Highland Technology, Inc
picosecond timing precision measurement
That's fine if you have short positive pulses and don't need DC coupling. To get DC, put a 5 volt zener or bandgap across the cap, and then you don't need the clamp diode.
You can probably skip the diode anyhow. HC logic has pretty good ESD diodes on the inputs.
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John Larkin Highland Technology, Inc
picosecond timing precision measurement
With current HC or AC or Tiny parts, paralleling sections works fine. They are well matched internally. Actually, we parallel multiple Tiny triple buffers, and that works too. If you source terminate, you can split the 50 ohm resistor into sections, one for each triple buffer.
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John Larkin Highland Technology, Inc
picosecond timing precision measurement
You don't get the full logic swing with a resistive shifter, so the driven gate can oscillate or go linear and get hot. The slow transition can cause shoot-through problems too.
With +5 and -5 supplies and equal resistors in the shifter, the lower gate sees +2.5 and +5 logic inputs relative to its Vee. Not good.
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John Larkin Highland Technology, Inc
picosecond timing precision measurement
i wonder, really, sure some cases you need to have a second source, some case ... But with a new chip coming out every week, how long are things available? That is one reason I like Microchip PICs, even the antique ones are still available.
I know, ebay: I have some bad MAX232, and LM35s that were clearly something else (got money back had the seller test it).
Smartphones are 'old' every 2 years, like cars...
It is a moving thing.
One should then design so the circuit does not so much depend on the parts used, that was the old way to design too, accommodating huge tolerances, you made the circuit so it could handle that. That is also why trimcaps and trimpots..
Took me a while to find a replacement LCD display with the same controller for something I designed, ebay helped out again. Else you need to rewrite the code.
More modular, so you can change a module if something fails, no matter what is in it.
Anyways, it is philosophy, if customer.. The Customer Is Always Right sort of thing. :-)
On that subject, I canceled my cable subscription yesterday, got fed up with their defective website interface and billing. Looks like I will go wireless, and then again ebay prices for the routers are half of what they charge here, The Customer Is King. :-) Now they should hurry up with that 5 G!
Everything, including computers and TVs and cars and printers and cameras and phones and, well, everything, should be one wireless 5G network. We're still in the Dark Ages of computing.
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John Larkin Highland Technology, Inc
picosecond timing precision measurement
Most of the fine features will only be available, when the nearly 30 GHz band is actually in use and there is a base station/access point in every light pole (small cell, good frequency reuse and manageable RF path loss: -).
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