EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: george graves on August 12, 2014, 09:12:39 am
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Name and shame them....What parts always end up biting you in the ass.....
Or...What parts have you worked with that ended up causing a problem/re-design/smoke/fire....
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Name and shame them....What parts always end up biting you in the ass.....
I see, this is an intelligence test, one which those that admit to repeated application of duff parts fail.
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there is none. all parts are just parts. i use only parts i like and which are available and suitable (hobby projects).
but what i really hate is the marketing bullshit on the first page of the datasheet - and that apply for the vast majority of the parts ;)
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I see, this is an intelligence test, one which those that admit to repeated application of duff parts fail.
We don't always get the choice. I dislike using anything that comes in a QFN or similar package, because even when manufacturers swear they can handle them with no problems at all, I just know I'll end up looking for open circuits where they've not soldered properly. Not ideal when you're trying to find the *real* bugs on a first prototype.
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I ordered vishay VLM#1300 smd LEDs. I swear to god, they are made out of candle wax and spit. No matter how careful I solder them, a few always fall apart or die a heat death.
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TQFP and like with 64 and more pins.
They are a pain to etch for and solder.
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Anything that I've designed in before reading the errata :palm:
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parts where the pins are so close together that even with a pro stainless steel SMD stencil the state/temperature/fluidity of the solderpaste matters if you have a lot of shorts between the legs or a perfect reflowed result.
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Connectors with unclear mechanical and footprint dimensions on the datasheet. |O
Tremendous afternoons passed with connector, gauge, pencil & paper. :rant:
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Any SMD part that doesn't have exposed pins. Can't measure anything, can't remove it (easily) and can't visually inspect the connections.
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Cheap chips from eBay with marginal stability (factory rejects / pirate copies / crap). I guess I'll never learn ::)
Last time it was a MC34063 which I figured was to cheap to copy, but of course it ended up widlarized together with its cheap brethren.
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Anythng that looks like a glass balloon with bits of scrap metal in it...
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Parts that don't have datasheets of them.
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I hate working with Infineon parts. I worked for them and it was a terrible experience. I was glad to get another Job. Using Infineon products brings back bad memorys.
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Marvell and Qualcom parts, for their stance on datasheets and two-row QFN packages that need 3.5 mil t/t on outer layers to route.
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Connectors with unclear mechanical and footprint dimensions on the datasheet. |O
Tremendous afternoons passed with connector, gauge, pencil & paper. :rant:
OMG yes! Hirose parts are terrible for this... I mean they specify the font and embossing depth of the manufacturer logo, but if you want the distance between rows of pins center-to-center, you need to print out the PDF at 12000DPI and look with a microscope.
Or they specify so many other dimensions, so that three people arrive at four different results...
argh.
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Yep. Molex has that tendency too. A hundred measurements all referencing each other so you have to break out graph paper and an abacus to get the one dimension you care about.
The other part (vendor) I hate is E-Switch. They always have HAD exactly the switch I want.
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AMD Processors... they are packed full of the magic smoke.
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Yep. Molex has that tendency too. A hundred measurements all referencing each other so you have to break out graph paper and an abacus to get the one dimension you care about.
The other part (vendor) I hate is E-Switch. They always have HAD exactly the switch I want.
I hate that also.
Datasheet space is free... so why they leave important dimensions to be derived from other dimensions makes no sense. It always reeks to me of an overly eggheaded engineer who abhors redundancy even at the expense of ease of use.
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AMD Processors... they are packed full of the magic smoke.
Where did you see at least a single one?
Except that 15 years old video on youtube.
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AMD Processors... they are packed full of the magic smoke.
Where did you see at least a single one?
Except that 15 years old video on youtube.
Nothing in the last 5 years since I changed professions (I'd like to think AMD have sorted out their overheating/self-destructive features properties). I personally swore off them back when the AMD K6 was around. Since then, I've seen several crispy AMD's first-hand in other machines I've worked on over the course of 10+ years in IT industry.
(Although the YouTube videos are amusing too!)
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Chips where the details needed to repurpose or hack the devices containing them are unavailable.
FPGAs are my current love/hate. They are really fun to play with, except there are so many rules in how to make a working design. Tiffany Yep makes it all look so easy, except it's not...
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DIN connectors. The type used in 30 year old AV equipment.
They short-out/melt and do all the things you don't want - before you try to shoehorn the conductors, insulation and strain relief back into that 1/2-inch cylinder.
AArgh
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Heh. And what could possibly be the problem with using the same connector for power, serial, and A/V signals?
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Anythng that looks like a glass balloon with bits of scrap metal in it...
How are you going to reheat your pizza without one of those?
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This part was a nightmare:
http://www.analog.com/static/imported-files/data_sheets_obsolete/311507236AD9501.pdf (http://www.analog.com/static/imported-files/data_sheets_obsolete/311507236AD9501.pdf)
Analog devices made a series of these programmable delay generators, with either TTL or ECL outputs. They were garbage. They were extraordinarily sensitive to noise on any pin and next to unusable in almost any logic environment. Several 10's of uV on a logic pin and the internal comparator would trigger erratically on the internally generated analogue ramp voltage. The whole series is obsolete now - I think I know why.
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Connectors with unclear mechanical and footprint dimensions on the datasheet. |O
Tremendous afternoons passed with connector, gauge, pencil & paper. :rant:
LCD displays (hurray for cheap Chinese drafting labor?) and connectors (FPC and others) seem to be the worst offenders.
Regarding redundancy: you're not required to note dimensions that are fully defined elsewhere, and often, you don't want to. However, there is still a recognized method to do so: the measurement is written in parenthesis, indicating a derived value, as a note, not as a design reference. (Thus, the tolerance on that number may be substantially worse than those around it; this isn't necessarily the case, like if you have a row of pins with pin-to-pin spacing "<number> +/- <tol> NON CUM.", then call out the number of pins. The dimension between outermost pins will be both a derived value, and having tolerance exactly <tol> because it's non-cumulative.)
I hate working with Infineon parts. I worked for them and it was a terrible experience. I was glad to get another Job. Using Infineon products brings back bad memorys.
My condolences -- that sucks, from anywhere.
That's not what I've heard about them though, at least recently. I've even had a few questions answered reasonably and promptly, at least from those respective departments. Their parts are generally good quality and sufficiently specified.
Tim
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LCD displays (hurray for cheap Chinese drafting labor?) and connectors (FPC and others) seem to be the worst offenders.
Ouch you woke up an very old frustration:
Those LCD zebra stripes , if you do not have the perfect 100% balanced mechanical pressure over the entire display some digits will not work |O
And those once clipped on connectors are also bad when they are corroded, they can break off when you are only looking at them :D
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Nothing in the last 5 years since I changed professions (I'd like to think AMD have sorted out their overheating/self-destructive features properties). I personally swore off them back when the AMD K6 was around. Since then, I've seen several crispy AMD's first-hand in other machines I've worked on over the course of 10+ years in IT industry.
(Although the YouTube videos are amusing too!)
They have internal thermal protection/throttling since Athlon 64 and that was 10 years ago. Before that they did have a temp sensor but purely relied on motherboard that it will handle overheating correctly (often they did not).
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PIC16, PIC18, dsPIC30 - bugs on bugs chasing bugs which are being fed with bugs. Bastards owe me several weeks of my life which I spent chasing silicon bugs that sometime weren't even in errata sheet.
Chinese 'bead' 1W LEDs - i have yet to score a success on reflowing those in an oven without lens melting.
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Flat flex and its connectors. I've broken a lot of them when trying to work out how they operate -- every laptop seems to use at least 2 different latch styles. The tiny plastic arms/fingers that hook them into place or guide them commonly can't take a 'normal' opening force if you operate them in the wrong direction.
A bright light and a lot of patience pay off :)
Corroded flat-flex is another story. Keep your old electronics dry!
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Chinese 'bead' 1W LEDs - i have yet to score a success on reflowing those in an oven without lens melting.
I've done "3W" Chinese LEDs by 'hot stove reflow' on copper clad. Your oven isn't heated from the top by any chance, is it?
I've desoldered 7-seg displays before, that kind of gooed to bits trying to pull them out... :(
Tim
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Anythng that looks like a glass balloon with bits of scrap metal in it...
A Hewitt Mercury Arc Rectifier?
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I hate Murata's DLW family of common mode chokes. Is it so hard to add an orientation mark to a symmetrical component?
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LCD displays with M2.5 mounting holes when they have enough room on the PCB to make M3 holes, and parts with unclear pin function descriptions (does that pin have any practical use or not :wtf:).
I also really hate inductors with crap datasheets which doesn't specify the core material and/or operating frequency range. It should be a technical document not marketing crap.
QFN packages are also on the list although TQFP are perfectly fine. The only advantage I see in QFN is the small footprint but that is usually outweighed by the difficulty to solder/desolder them. That bloody annoying thermal pad on the bottom ruins everything.
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I've had good luck with QFN packages, yet seem to always have soldering problems with TQFP's... Guess this is very much a YMMV kind of thing.
That said, I also have lots of problems with SMT LEDs... they seem unusually susceptible to damage from reflow soldering, and this is with leaded-solder; I can only imagine how well they do with lead-free soldering.
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I like the QFN/DFNs :) - the ones I hate are the ones only available in SOIC.
I recently designed in some ADG5412 switches in LFCSP packages from the datasheet only to find when I got the boards back to make up ... that no one actually stocks the LFCSP. My stupidity I guess, but why do they have that package on the datasheet if they don't actually make it available?
Alan
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I like the QFN/DFNs :) - the ones I hate are the ones only available in SOIC.
I recently designed in some ADG5412 switches in LFCSP packages from the datasheet only to find when I got the boards back to make up ... that no one actually stocks the LFCSP. My stupidity I guess, but why do they have that package on the datasheet if they don't actually make it available?
Alan
YES! That is another huge issue I hate dealing with. A lot of companies will have tons of variations and then none of them are ever available. When you inquire, they will tell you that there will be a MOQ of 10,000 or 20,000pcs. Even for large companies - who would commit to 20k of something you can't even get a few of for testing?
And actually, Cree is notorious for this with LED's... they will list tons of CRI and flux bins, and they will hype their latest LED to the max about how it produces 200lm/watt at 95CRI or some nonsense. Then you see there are a couple of reels available at the distributors' websites in 80CRI and 90lm/watt flux bins... and the sales droids will tell you they can happily supply the higher flux bins (at triple the price) if you're able to commit to 50k pcs orders. Ridiculous.
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Amen on
die the Cree thing!
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Minor gripe: TI's TPS54226 switching regulator. There's an Enable pin, and a Vreg pin that supplies 5v for control circuitry. The Enable pin is diagonally opposite from the Vcc pin (with a ground pad between) but in my layout, the Vreg pin was fairly easily accessible, so I thought "OK, I'll tie Enable to Vreg". Predictably, it turns out Vreg is ALSO disabled when Enable is LOW, so my prototype board had a bit of a chicken and egg thing going on.
To be fair, I realized this was a possibility, and combed through the datasheet looking for confirmation one way or another -- and therein lies my chief complaint. There isn't one word about this either way. In the block diagram, Enable goes to a single isolated block labelled "Enable Logic". In the application circuits, Enable goes to an external header. In the timing diagrams, the sequencing is shown between Enable, Vout, and PowerGood, but not Vreg. In the text, not even a single paragraph is devoted to Enable's function.
For an essential (albeit trivial) signal, there's not much attention given to how it works.
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I like the QFN/DFNs :) - the ones I hate are the ones only available in SOIC.
As Long As you design the pads to stick out at least 0.5mm from the side of the package, DF/QFns aren't too bad, and are in some respects easier to rework than QFPs - no bent /lifted pins, and no solder wicking up between pins.
I don't like the ones that need a die slug soldering down though as this severely limits space for routing tracks
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I like the QFN/DFNs :) - the ones I hate are the ones only available in SOIC.
As Long As you design the pads to stick out at least 0.5mm from the side of the package, DF/QFns aren't too bad, and are in some respects easier to rework than QFPs - no bent /lifted pins, and no solder wicking up between pins.
I don't like the ones that need a die slug soldering down though as this severely limits space for routing tracks
If you ever worked with LCCs in the 80s you will realise that the die slug is critical for sustained mechanical strength over many temperature cycles with a QFN. For RF parts it is also critical for performance, but I believe its present on most parts for mechanical reasons.
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Parts with shit datasheets - http://www.st.com/web/catalog/sense_power/FM89/SC444/PF250725 (http://www.st.com/web/catalog/sense_power/FM89/SC444/PF250725) for example.
Has a nasty 3mm square LGA-16 package to boot.
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LT3652 in 3X3 mm DFN pacakage
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I hate Murata's DLW family of common mode chokes. Is it so hard to add an orientation mark to a symmetrical component?
Specifically, the -5BS/BT? That looks terrible...
Tim
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Anythng that looks like a glass balloon with bits of scrap metal in it...
How are you going to reheat your pizza without one of those?
One of those ceramic or nichrome heating elements.
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My pet hates right now are diodes that don't have cathode markings, chips where the pin 1 orientation is marked on the bottom of the chip, datasheets which show the pinout looking at the chip from below, molex put every component in the same parameterised drawing BS - only to be beaten by datasheets where it isn't possible to tell whether the pinout is shown from the top or the bottom. I'm getting a bit worked up now (!) - you must have touched a nerve...
Alan
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... chips where the pin 1 orientation is marked on the bottom of the chip
Curious which chip is that ? :o
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datasheets which show the pinout looking at the chip from below
This is not uncommon with relays - and ought to be punishable by public flogging ::)
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Anythng that looks like a glass balloon with bits of scrap metal in it...
Aw that was just mean. ;)
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[/i], datasheets which show the pinout looking at the chip from below
Oh yes. Mr Smoke there you go, revision 2 here I come.
I also dislike the SOIC, where the orientation is where the mold is thinner (becasue just printing a dot is so 20 century), but my favourite are the ICs where the datecode or some other BS is on the bottom.
For the Infineon haters, I totally agree. I refuse to design with anything infineon which has more than 2 PN junction or three pin.
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Chip-like parts with clockwise pin numbering from the top-right.
That was a Mini-Circuits part, years ago...
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Minor gripe: TI's TPS54226 switching regulator. There's an Enable pin, and a Vreg pin that supplies 5v for control circuitry. The Enable pin is diagonally opposite from the Vcc pin (with a ground pad between) but in my layout, the Vreg pin was fairly easily accessible, so I thought "OK, I'll tie Enable to Vreg". Predictably, it turns out Vreg is ALSO disabled when Enable is LOW, so my prototype board had a bit of a chicken and egg thing going on.
To be fair, I realized this was a possibility, and combed through the datasheet looking for confirmation one way or another -- and therein lies my chief complaint. There isn't one word about this either way. In the block diagram, Enable goes to a single isolated block labelled "Enable Logic". In the application circuits, Enable goes to an external header. In the timing diagrams, the sequencing is shown between Enable, Vout, and PowerGood, but not Vreg. In the text, not even a single paragraph is devoted to Enable's function.
For an essential (albeit trivial) signal, there's not much attention given to how it works.
Actually there is written quite enough. Part of it:
TPS54226 discharges the output when EN is low, or the controller is turned off by the protection functions (OVP,
UVP, UVLO and thermal shutdown). The output is discharged by an internal 50-? MOSFET which is connected
from VO to PGND. The internal low-side MOSFET is not turned on during the output discharge operation to
avoid the possibility of causing negative voltage at the output.
In the specs max EN voltage = Vin
And how do you imagine that EN would work at all if there is no high voltage on it. Voltage cannot appear on the output in principle with EN disabled.
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Yes, the datasheet at least tells you the acceptable voltage range of En, and that it will disable the output. However, I don't follow how your quoted text defines the relationship between En and Vreg -- being the main point of my gripe. (To be clear, Vo != Vreg. They are two distinct regulators.)
On one hand, you might assume Vreg will be disabled -- it's a regulator, and you might want to have control over whether it's enabled.
On the other hand, you might assume Vreg will NOT be disabled -- it exists for control of the switching regulator, so it should be available to... control the regulator.
It took a failed prototype to determine that Vreg is in fact disabled when Enable it de-asserted. No biggie, but that would have been nice to know before wasting ~$20 on a board and some parts, and a couple weeks for turnaround. In hindsight, I should've just broken out the pins so I didn't have to re-spin the board if I guessed wrong. C'est la vie.
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Now understood that you talked about separate regulator. The thing is, seems that is not intended to connect anything to it at all except capacitor and PG resistor. Basically it exists as separate pin only because of the capacitor.
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I dislike large lead count parts which do not come in PLCC (J-Lead) packages and anything smaller than small outline packages except for sot-23 style packages.
I also dislike the 555 because it suffers from noise induced by cross conduction when switching.
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>>> Curious which chip is that ?
The LT6017 in DFN - theoretically it should have top side marking but even under a microscope you can't see it so you have to look at the copper underneath - where there's a corner cut-off. One of the diodes I was talking about is the ZHCS400 which has BD written on it - B is the anode.... :-[
A.
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When I add a 555 to my breadboard, I always do so begrudgingly. The active-low reset and VCC (often shorted) are at opposite corners, the control and ground (decoupling cap) are at opposite corners, and the trigger and threshold (often shorted) are on different sides. All this means I can never satisfy my desire to make very neat and compact breadboard layouts with a 555. I really wish there was a more breadboard friendly variant.
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Any SMD part that doesn't have exposed pins. Can't measure anything, can't remove it (easily) and can't visually inspect the connections.
+1
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LCDs and I2C devices. In both cases you can guarantee that the designer was suffering from severe brain damage when he created the interface. With LCDs they usually require you to use annoying image formats and poorly documented commands, mostly to save money in the controller hardware. With I2C devices there isn't even a standard for basic stuff like register access, so everyone comes up with their own slightly different and incompatible system.
I remember once working with an I2C LCD. It had a 16 bit register named as "contrast". After suffering for 2 days, I realised that this register has to be written with the correct value, and that is why nothing else seems to work. Yeah, why would be the reset value useful?
So then I started randomly writing numbers to it... nothing. Finally I wrote a code, which incrementally wrote every single value to this 16 bit, and I was sitting there with a stopwatch in my hand to figure it out which value was almost good. Ther was about 30 or so values which made anything visible on the screen.
Datasheet is useless chinglish.
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LCDs and I2C devices. In both cases you can guarantee that the designer was suffering from severe brain damage when he created the interface. With LCDs they usually require you to use annoying image formats and poorly documented commands, mostly to save money in the controller hardware. With I2C devices there isn't even a standard for basic stuff like register access, so everyone comes up with their own slightly different and incompatible system.
There isn't even a good hardware spec, I2C is too old to account for all the various voltages used these days so you need I2C level translators liberally spread around your design.
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On one side I love STM32xxx processors for their rich features, on the other side I hate them for their pinout from hell - seriously, how can you distribute one ~16 signal interface over THREE sides of a 4 sided 100 pin mixed up pretty much with everything right around the analog pins? There's a fair amount of similar examples - the SDIO interface is on two sides with pins not next to each other... seriously... WTF? :wtf: :wtf: :wtf:
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Anything small (QFN etc) with a thermal pad
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Antennas from reputable manufacturer without at least one radiation pattern in their datasheet. :-// :wtf:
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On one side I love STM32xxx processors for their rich features, on the other side I hate them for their pinout from hell - seriously, how can you distribute one ~16 signal interface over THREE sides of a 4 sided 100 pin mixed up pretty much with everything right around the analog pins? There's a fair amount of similar examples - the SDIO interface is on two sides with pins not next to each other... seriously... WTF? :wtf: :wtf: :wtf:
+1
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On one side I love STM32xxx processors for their rich features, on the other side I hate them for their pinout from hell - seriously, how can you distribute one ~16 signal interface over THREE sides of a 4 sided 100 pin mixed up pretty much with everything right around the analog pins? There's a fair amount of similar examples - the SDIO interface is on two sides with pins not next to each other... seriously... WTF? :wtf: :wtf: :wtf:
I second the sentiment, but will say it's a pretty common problem for the larger microcontrollers... A couple years ago I was working with the LPCxxxx (don't recall) and its external memory bus was almost literally every other pin around the QFP. It's pretty clear the when the manufacturers figure everyone is using a 4+ layer board and will just dump things on their own layer so the pinout isn't that vital |O. I've actually found the STM32 F0 and F1 to be not that bad, in terms of at least bunching the GPIO in groups of 8 and generally keeping alternate functions close. I've definitely seen much worse.
That said, the STM32F030F4P6 is a chip I (love to) hate working with. It's an ARM in a TSSOP20 for ~$1 (esp via AliExpress). The problem: 9 of I/O are basically just GP and all the dedicated functions are grouped on the other 6. To add insult to injury, the bootloader ROM uses the only locations for I2C (and other funcs) for its UART, when the UART could be multiplexed on pins that have no other functions :palm:.
And with that I will add a more general gripe: datasheets that advertise a lot of functionality without mentioning that not all of it is actually usable, either because of shared resources or because it's simply not present on some versions of the device.
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I second the sentiment, but will say it's a pretty common problem for the larger microcontrollers... A couple years ago I was working with the LPCxxxx (don't recall) and its external memory bus was almost literally every other pin around the QFP. It's pretty clear the when the manufacturers figure everyone is using a 4+ layer board and will just dump things on their own layer so the pinout isn't that vital |O.
Agreed! I've been working with a few ICs lately that seem to be designed by people who enjoy making your life difficult. "Keep the Clk pin as far away as possible from analog signals and power planes." That would be the Clk pin between Vcc and A+? Got it. I'll try and steer clear of those two adjacent pins, then. ::)
My previously griped TI switching regulator has this problem too. A much cleaner layout could've been achieved by juggling a few pins around.
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Toroid/binocular cores. I've noted the number of wire turns achieved before losing count is age related. 1,2,3,4,5,6.... 7,8,9...
Balls!
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Tiny packages. I just added two ICs to my design which are only available in 1.5mm by 1.5mm WSON6 packages... (2xBQ29700)
I haven't tried yet, but I'll probably inhale them before I can solder them.
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Anything from Atmel. If their datasheet states in bold that a device runs from 3.3V it doesn't. It's more like 3.6V but that is only in the fine print.
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Anything from Atmel. If their datasheet states in bold that a device runs from 3.3V it doesn't. It's more like 3.6V but that is only in the fine print.
It can, but at degraded performance/clock?
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Anything from Atmel. If their datasheet states in bold that a device runs from 3.3V it doesn't. It's more like 3.6V but that is only in the fine print.
It can, but at degraded performance/clock?
Not even that.
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Anything from Atmel. If their datasheet states in bold that a device runs from 3.3V it doesn't. It's more like 3.6V but that is only in the fine print.
It can, but at degraded performance/clock?
Not even that.
the whole world is using atmel mcus at 3.3V running at reduced clock of 8 MHz or less... so think about it a bit ;)
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Anything from Atmel. If their datasheet states in bold that a device runs from 3.3V it doesn't. It's more like 3.6V but that is only in the fine print.
It can, but at degraded performance/clock?
Not even that.
the whole world is using atmel mcus at 3.3V running at reduced clock of 8 MHz or less... so think about it a bit ;)
You should read more carefully. I wrote IF an Atmel datasheet says the lowest voltage is 3.3V then you shouldn't run the device at 3.3V or you will get burned sooner or later. It is an example of what you can encounter. Other manufacturers like NXP or TI are way more honest about their devices.
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That's interesting, I have always considered Atmel to be pretty good with their datasheets. Very descriptive if you read them thoroughly
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I have avoided Atmel products in the past because of their poor datasheets. There are examples of even worse datasheets like from Allegro but that does not make Atmel's datasheets any better. TI's datasheets have gotten significantly worse over time but I have other reasons to avoid their parts.
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Atmel's documentation is usually clear, well formatted, sufficiently redundant (similar sections are often near copy-paste -- saves on time having to read through different sections), and well enough explain the code or registers or logic or whatever. They do lack in the implementation / detailed / analog department though. Example: the crappy ADC, BOD and POR in the ATmega series, and good luck finding any guaranteed min/max parameters on them (even a lot of typ are missing).
Also the same sorts of things from Altera: good luck finding I/O pin characteristics, power supply specs (bypassing, current consumption..), that sort of thing.
Tim
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Atmel's documentation is usually clear, well formatted, sufficiently redundant (similar sections are often near copy-paste -- saves on time having to read through different sections), and well enough explain the code or registers or logic or whatever. They do lack in the implementation / detailed / analog department though. Example: the crappy ADC, BOD and POR in the ATmega series, and good luck finding any guaranteed min/max parameters on them (even a lot of typ are missing).
Also the same sorts of things from Altera: good luck finding I/O pin characteristics, power supply specs (bypassing, current consumption..), that sort of thing.
Tim
Yeah I agree with this. To be honest I suppose it depends on what your expectations are. Any consensus on what microcontroller manufacturer has more detailed datasheets than atmel?
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Not something I've researched thoroughly at all, but I've looked at an MSP430 or two and they seem to document things well enough. They're more powerful (16 bit, and usually faster and more features), and very popular, especially for low current consumption purposes (switchable low power clock options, low operating current in general).
Anyone else?
Tim
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Not something I've researched thoroughly at all, but I've looked at an MSP430 or two and they seem to document things well enough. They're more powerful (16 bit, and usually faster and more features), and very popular, especially for low current consumption purposes (switchable low power clock options, low operating current in general).
Anyone else?
Tim
I've used several MSP430s in different projects, and have never found anything significant lacking in TI's documentation. I find them quite pleasant to work with actually, provided they fit the requirements of the application. I have found a few small bugs in GRACE and of course I hate CCS with a passion and IAR isn't too far behind, but mspgcc works well.
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BNC connectors. I loathe and love them at the same time.
I love the fact that a well shielded SDI cable with BNC connectors will pass data at multi-gigabit speed. And I love the fact you twist to close it.
I also loathe the fact you twist to close it, and that innevitably the connector on the 10000+ euro broadcast equipment feels incredibly flimsy. And that the slightest pull on the cable (because once you've connecte a bnc cable it can never be disconnected again by twisting... I'm looking at you Sony broadcasting equipment) feels as if the entre socket will pull out.
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BNC connectors. I loathe and love them at the same time.
I love the fact that a well shielded SDI cable with BNC connectors will pass data at multi-gigabit speed. And I love the fact you twist to close it.
I also loathe the fact you twist to close it, and that innevitably the connector on the 10000+ euro broadcast equipment feels incredibly flimsy. And that the slightest pull on the cable (because once you've connecte a bnc cable it can never be disconnected again by twisting... I'm looking at you Sony broadcasting equipment) feels as if the entre socket will pull out.
TNC connectors have the solid feel that BNC connectors lack and are easier to use than SMA connectors in test equipment. Since TNC connectors are basically deprecated, I have grown to like SMB connectors in place of SMA connectors.
One of the pleasant surprises I had when first working with GR-874 connectors is how solid they felt.
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fake/copy chips... i hate theme.
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I see, this is an intelligence test, one which those that admit to repeated application of duff parts fail.
We don't always get the choice. I dislike using anything that comes in a QFN or similar package, because even when manufacturers swear they can handle them with no problems at all, I just know I'll end up looking for open circuits where they've not soldered properly. Not ideal when you're trying to find the *real* bugs on a first prototype.
I would agree wholeheartedly. QFN/DFN parts ( I have been using these for power MOSFET H-bridge drivers, lately) are horrible, when a hobbyist or small-timer like myself doesn't have an X-ray machine to check solder joints. Another horrible part is the SMD HDMI type A connectors I have been forced to use (from Molex). This thing puts all 19 pins in a single row adjacent to the main shell. The clearance is (almost) 0.5mm pitch, and therefore allows at max 6-8mil geometry to run the signals out. Try to hand assemble a board with one of these. Half the time the traces just evaporate before the solder joints are solidified. Next time I am going to try to get connectors from Adam, which just announced double offset rows of through pins on their connector.
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Half the time the traces just evaporate before the solder joints are solidified. Next time I am going to try to get connectors from Adam, which just announced double offset rows of through pins on their connector.
Solder iron about... 200C too hot???
Tim
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Certain MGA series LNAs from Avago. Those are so sensitive to ESD, that a single wrong touch can fry them.
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There is nothing worse than fake parts from otherwise (at least we thought) genuine supplier.
I've got parts for a school project (power fets) and they were OK, but the next batch were all fakes. Apparently some half-wit in their management thought that they will make more money if they buy from some chinese reseller and didn't even bothered to check if it meets the spec (and it didn't by far)...
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Half the time the traces just evaporate before the solder joints are solidified. Next time I am going to try to get connectors from Adam, which just announced double offset rows of through pins on their connector.
Solder iron about... 200C too hot???
Tim
SMD parts with hot air at 260C and at least 3" distance from the joint to the air tool tip. Effective temp at the copper is about 160C.
The Adam parts will allow me to use 10mil traces from the pins, which should improve my disposition something wonderful.
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LCD drivers from Princeton Tech. The serial interface is a bad an sad joke. Total pain in the ass to write software for if that software is to be even remotely efficient. Same thing goed for other chinese products that have derial interfaces.
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You should read more carefully. I wrote IF an Atmel datasheet says the lowest voltage is 3.3V then you shouldn't run the device at 3.3V or you will get burned sooner or later. It is an example of what you can encounter. Other manufacturers like NXP or TI are way more honest about their devices.
Which parts are you referring to specifically?
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I hate 27K resistors.
Not a technical thing; more like a phobia :-P
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You should read more carefully. I wrote IF an Atmel datasheet says the lowest voltage is 3.3V then you shouldn't run the device at 3.3V or you will get burned sooner or later. It is an example of what you can encounter. Other manufacturers like NXP or TI are way more honest about their devices.
Which parts are you referring to specifically?
All digital chips from Atmel.
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You should read more carefully. I wrote IF an Atmel datasheet says the lowest voltage is 3.3V then you shouldn't run the device at 3.3V or you will get burned sooner or later. It is an example of what you can encounter. Other manufacturers like NXP or TI are way more honest about their devices.
Which parts are you referring to specifically?
All digital chips from Atmel.
Many atmega parts go down to 2.7V or even lower. Be more specific.
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Read more carefully what I wrote before: the 3.3V is just an example. If Atmel says a device will run at X volt then add approx 0.2V/0.3V to X to know at which voltage a device actually works reliable.
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I hate 27K resistors.
Not a technical thing; more like a phobia :-P
I have a better one: 15 ohm resistors.
Don't get it? Consider this... What color is a 1M resistor? :-DD
Tim
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Personally I hate working with any of the PIC 12, 16 or 18 series. The datasheets are fine and they are cheap, reliable parts, but the IDE sucks and their architecture is horrible. These days there is little reason not to use a 24 series though.
The PIC instruction set architecture always reminds me of the 6502. A little bit of macro assembler messaging can improve the situation for those not comfortable with accumulator based ISAs.
I might prefer Atmel's 8-bit ARV except for the previously mentioned problems with their documentation. I also have concerns about ongoing availability of Atmel parts.
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The PIC instruction set architecture always reminds me of the 6502. A little bit of macro assembler messaging can improve the situation for those not comfortable with accumulator based ISAs.
Why do you think a PIC is like a 6502? The PIC is Harvard like. The 6502 has a single address space architecture. I would have thought that gave them a very different feel.
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Not high temperature wire you have to solder to a board...with insulation melting and retracting before you try to solder it ! |O |O |O
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The PIC instruction set architecture always reminds me of the 6502. A little bit of macro assembler messaging can improve the situation for those not comfortable with accumulator based ISAs.
Why do you think a PIC is like a 6502? The PIC is Harvard like. The 6502 has a single address space architecture. I would have thought that gave them a very different feel.
The separate address spaces hardly make a difference in most microcontroller applications where firmware will be fixed. The PIC still supports immediate operands even though immediate data gets pulled from the program address space instead of the unified address space.
The programming environment for a processor with unified address space treats program address space and data address space separately most of the time anyway.
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What parts always end up biting you in the ass.....
Early Luminary parts fall into that category. Thank God that TI bought them out.
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the crappy ADC, ... in the ATmega series
The ADC modules in many Atmel chips are actually quite unique in terms of its differential inputs and user configurable gains. You rarely see that in low-priced chips, even among 32-bit chips.
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I hate 27K resistors.
Not a technical thing; more like a phobia :-P
I have a better one: 15 ohm resistors.
Don't get it? Consider this... What color is a 1M resistor? :-DD
Tim
The last ones I saw didn't have any colors.. but they were RN 55C 's :phew:
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I have a better one: 15 ohm resistors.
Don't get it? Consider this... What color is a 1M resistor? :-DD
Tim
Reminds me of when I was about 14, very early 70's before I had a scope, and I made this valve amplifier and used a 15 ohm resistor from grid to ground instead of a 1M. Eventually gave up on trying to make it work and pulled it all apart again. I think I actually nicked that resistor from the parts shop too. :palm:
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At the moment, panel meters. Trying to get them working when you have one supply can be a PITA especially when you order them, theres no info saying they can't have common ground (or worse, say they can, but turns out its only on a 20V range, not a 200mV range). Then if you get a common ground one you cant sense two parts in series on a loop :palm:
I don't get why they cant just work properly as differential meters like they should.
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I don't get why they cant just work properly as differential meters like they should.
Because that would be hard!
To be fair, good analog isolation is still a persistent challenge. Your best bet is usually to put in a completely isolated supply and let that be that.
Tim
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Never really got a problem with any parts as such, I find that part of electronics fun.
I HATE wiring though...
I've built a modular synthesizer (https://www.eevblog.com/forum/projects/anyone-else-building-an-analogue-synthesizer-here/), and I can tell you the absolute worst part of that is hand wiring all the sockets and switches & LEDs from the panels to the PCB.
I've got the solid wire earth loop down to a fine art, but hate, HATE, HATE stranded wires.
Ok, another pet hate is lead-free solder... The RoHS crew can go shove their tin-whiskers in their landfill (but that's another rant altogether)...
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LCD displays with M2.5 mounting holes when they have enough room on the PCB to make M3 holes
Heh, definitely this.
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I hate working with Teflon insulated wire. It is sooo unbelievably hard to strip. You actually need a heated blade wire stripper to do the job properly. And it feels kind of greasy too.
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You can do a pretty darn good job with a sharp blade, scoring around -- trouble is, nick the wire and it's toast!
Tim
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I hate working with Teflon insulated wire. It is sooo unbelievably hard to strip. You actually need a heated blade wire stripper to do the job properly. And it feels kind of greasy too.
What kind of temperature does your heated stripper run at if it melts Teflon? I hope its used with a really efficient extraction system, because things get pretty noxious when you get Teflon that hot.
Teflon insulated wire strips very easily with the kind of stripper that brings together two semicircles of just the right size. I used to use tons of the stuff until it was banned from most applications because of the fire hazard. Are you using Teflon insulated wire for RF purposes?