Many of us use parts off-label, often very successfully. A few examples:
SAV-551+ pHEMTs make very good wideband bootstraps. Their f_max is around 12 GHz, but they're amazingly stable.
74HC4352s make good flying-capacitor diff amp front ends.
TMUX1511s make very nice analogue lock-ins--their Coff*Ron FOM is almost in a class with relays, but 1E5 times faster.
Zero-ohm jumpers have about the right resistance to stabilize LDO regulators with ceramic output caps. (It's good to be able to disconnect the supplies during bring-up, and putting the jumper between the reg and the output cap has this additional benefit.
Phil Hobbs (*) who may be bulegoge's good twin, given the similarity of their emails ;)
The TL431 can be used as a multiple-feedback filter real easy particularly with a 5 volt supply; the 2.5 volt reference is the "virtual ground" and you only need the inverting input. keeping in mind its adjust pin draws more current, 10s of microamps, than the average bipolar op amp.
Common-anode 7 segment red LED display and 5 volt supply just use a TL431 connected two-terminal between the display anode and supply and drive the segments to ground with a uP, constant voltage and no current-limiting resistors needed. Seems to be just about the right brightness and very temperature stable with every red 7 segment I've tried.
kind of like toilet paper, duct tape, and WD-40 as a lubricant, the TL431 is good at many tasks except the one it says on the label.
The LM386 is good for driving small brushed DC motors and the DIP package can dissipate a lot of power and is very rugged. (thought I guess that's technically in the data sheet but not really elaborated on)
I'm fond of transistors, diode-wired, for thermometry. As an added fillip, one can make a current-source two wire sensor by biasing the sense diode with a four-wire fleapower regulator (1.2V feedback pin) powering both a load resistor and a pullup/pulldown pair (resistor pullup, resistor series with diode pulldown) to divide down and connect at the feedback pin. The regulator input current then is a function of the temperature, and independent of wiring resistance.
Another favorite off-label item, is an air-core inductor with a one-cent coin in the middle. Lots of current for a millisecond, and... shrunken coin. With enough power, shrunken quarter.
And if you ever need a bright point source, pencil leads only need a few volts to make a fine little arc lamp.
I've used them like that at your suggestion. Snazzy if you don't need super low offset voltage. (And if you do, every comparator slows way down.)
That's interesting. I recall discussing some very expensive parts sold specifically for DC isolating thermal pours.
Interesting. Are they reasonably repeatable unit-to-unit?
Interesting. How does that work? Normally I think of O/C tlines as a series resonance to ground.
Gotta watch for the antiparallel diodes on the inputs, though. For slow stuff, LM358s work great as comparators--the inputs survive going way above the supply.
Annoying that they don't tell you k in the datasheet, and you can't even back it out from the series-connected inductance, which is quoted as exactly four times the parallel-connected value.
Well, MCL is pretty good about keeping stuff in production.
Poorly specified ones, though--at least in 74HC, typical propagation delay specs are half of the maximum. Of course, my usual rule for one-shots is to avoid them unless the circuit would be okay over a 3:1 range of delays.
That one I haven't heard about. Are you looking for the NMR signal? ;)
BTW, did you find a good replacement for that discontinued Murata PV2A one that works up to 1-2 GHz?
Dunno, but maybe because high temperature engineering plastic is expensive. You could probably make them with graphite block bearings.
For modest values of reasonable. It's Is, which is huge for schottkies, hundred nA sorts of numbers. I've posted my RF detector which is a diode and a capacitor. It's in production.
Stick a drooling-rise step into one end of a transmission line and it will overshoot and snap up the waveform at the other end. Adjust the source impedance, or terminate a little, to trim the step response. It's sharper than RC peaking, so compensates things like Ft rolloff or skin effect.
I had a profound, life-changing revelation recently. If you don't poke a fast rise into a passive transmission line, you won't get a fast reflection. I wasted all those years designing absorptive lowpass filters.
The k's are really high. Easy to measure.
Yes, but they are little ones. The Avago SOT89s were great 1 amp, 1 pF, zero recovery diodes.
We are measuring timings and jitter to fs resolution by sweeping one edge across another, clock and D on a GigaComm flipflop, and averaging the Q output. I have some data if anyone's interested.
That's often all you need, some sort of glitch.
A conductive liquid is a shorted turn.
Don't think so. I'll check. Production hates them... hard to adjust.
We're putting fans on PCBs with angle brackets. A fan blowing directly on parts is wonderful thermally. Almost like they designed them to do that.
They could also put tapped holes at 90 degrees.
John Larkin Highland Technology, Inc
Science teaches us to doubt.
Okay, so not really open-circuited. I'll try it out. That could potentially have helped that single-diode sampler gizmo--its speed was limited by the rise time of the line receiver driving the pHEMT switch. That one used a capacitor plus a short, mismatched shunt stub to make the sampling pulse from a falling edge.
That's unusual for a 'coupled inductor'. I normally expect it to be around 0.85.
Right, I saved the schematic from when you posted it awhile back (2014). That was a 10EP52, which is now available only from Rochester. I'd be interested in the data and the updated version, sure. I'm sure I'll need to do that one of these days.
At sufficiently low frequency, anyway.
We've started putting little Sensirion T/H sensors in a lot of things. When using TECs, it's awfully nice to be able to compute the dew point, for instance, and in outdoor applications (e.g. our fire sensors for harvesters) it's good to be able to predict when the window is liable to fog up on the inside.
We use IP67+ enclosures with bags of 5A molecular sieve inside, which is super cheap and will absorb 50% of its own mass in water. Simon has had to learn a whole lot about enclosures and mechanical design generally. Turns out that you have to put an air vent on the enclosure to prevent pumping water inside due to atmospheric pressure differences. That leads to working of the O-ring seals, which wears them out.
We considered using a bellows, but atmospheric pressure varies +-7% or so, which makes for a pretty big, floppy bellows. Hermetic construction is possible but very expensive, and relies on glass or ceramic insulated connectors. The glass would have had to be brazed or indium-soldered to the lid, which leads to CTE mismatch problems.
Yup. Hard to replace for times you need them, though, e.g. gain peaking tweaks. You aren't doing that with a dpot.
ors with ceramic output caps. (It's good to be able to disconnect the suppl ies during bring-up, and putting the jumper between the reg and the output cap has this additional benefit.
Wow nice list! I'd like to take a 'part' off the alt. use list. I use to tout the use of 20 zeners rev biased at ~10-100 uA as audio noise sources. When I went to replace the pack I had it turned out I had a 'golden string'. I had to order a bunch from different suppliers to find noisy batch. (And that still wasn't as good(noisy) as the original... but it's obvious that almost no one wants a noisy zener.)
Historically, if the parts might be muffins, they did. The surface-flow fans on high-end video cards are axial-in/circumference-out air movers, a variant on the bottom-sucking sump pump designs of indeterminate age. Ducting (housing) gets in the way of IR for surface-mount parts, even if you can afford the materials.
So, you'd want to surface-mount a connector at the western edge of the footprint, and rout an aperture (or apertures) at the eastern edge, then after reflow, the fan hooks onto the aperture and swings down to mate with the connector. Wire-tie or latching connector keep it in place.
Or glue... but moving parts are best kept replaceable.
Huh, that's fun. you could play with the frequency. I had an axial inductor, (audio) Q went to hell after a water bath flux wash. I got better when dry, but took a while. (once found inductor was no longer immersed in water.)
The traditional way to discharge the cap would be a controlled current source, and you take the zero-crossing time to indicate the state of charge instead of using a fast ADC. That way, all cycles discharge the capacitor to the exact same level.