Good ICs to have lying around? - Page 1
Forum section: electronics / general

author: Phaedrus
author_rank: Frequent Contributor
timestamp: July 18, 2013, 08:32:09 pm
content: So we're setting up some simple prototyping stuff here, and I'm doing up a parts list for odds and ends that could be useful in the lab. Obvious things like 0603 1% and 5% resistor books and a 5% ceramic capacitor book, veroboard, etc. But also ICs.What ICs do you think would be essential to have on hand, especially for power applications?So far we've got:555, LM431 voltage reference, LM318 op amp, LM339 comparator, some 74HC logic including NAND and inverters, a number of GP and signal diodes including 1N4148s, some misc mosfets and BJTs, and a couple wicked fast ADCs from Analog (new project). We'll also have near-unlimited supplies of power mosfets, schottkys, bridge rectifiers, and a number of SMPS-specific ICs like Champion Micro CM6800 family and various TI parts. Also as many large electrolytics as you could want, and some random large inductors. Also grabbing an Arduino board to serve as GP MCU.Just realized we should pick up some zeners too.What else do you think might come in handy?

author: Jebnor
author_rank: Regular Contributor
timestamp: July 18, 2013, 08:34:09 pm
content: A couple Chopper OpAmps?

author: Dave
author_rank: Super Contributor
timestamp: July 18, 2013, 08:49:25 pm
content: Just do what everyone does: buy parts you actually need, when you actually need them. And when you are buying a certain part, order a few too many, so you have them at hand if you need them again.Ditch the Arduino, buy any microcontroller you like (NOT development board), study the datasheet, make your own circuit board and actually learn how to program. Slapping together poorly written libraries is not real programming.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: July 18, 2013, 09:16:57 pm
content: Just because I'm using the Arduino hardware doesn't mean I'm using all of their shitty libraries. It's a fast MCU with a bunch of interfaces on a pre-assembled board. If I need to do "real" programming, to the metal in assembly, I'll do so when I get to it. Bitching out Arduino when it serves for the application is just pointless.

author: c4757p
author_rank: Super Contributor
timestamp: July 18, 2013, 09:33:21 pm
content: You can't mention Arduino here without attracting the Arduino is Shit Brigade...There are valid criticisms of Arduino:The Arduino software is a sucky, poorly designed, slow turd for people too lazy to learn the software development cycle.The Arduino "shield"-and-related-crap ecosystem is an enabler for incurious "software people" who want to see LEDs blink but can't be bothered to read a datasheet or two. (Or learn to assemble components -someofthebreakoutboardsareridiculous...)But:The Arduino itself is a wonderfully convenient, minimalist AVR dev board with everything you need to quickly write a piece of test software and blast it off to the chip.People need to read before criticizing. "Serve as a GP MCU" seems to imply using it properly, I'd say...

author: Phaedrus
author_rank: Frequent Contributor
timestamp: July 18, 2013, 09:39:03 pm
content: Exactly. I just want something that I can write some C code for, compile, and transfer over USB. No fussing about with serial interfaces or any of that nonsense. Why bother if you don't have to?The shields are ridiculous though. I can't believe they can get away with selling a bit of veroboard with an IO header for that much... $7.50 for one board, or $7.50 for fifty boards. Hmmmmmm....

author: komet
author_rank: Unknown
timestamp: July 18, 2013, 09:41:07 pm
content: I bought much of the list that you mentioned during the course of my youth. For example, when I was 14 I bought a selection of various zeners. That was 25 years ago. I've just checked and it looks like I never used a single one of those zeners. The same goes for many of the ICs, but I don't know where they are.The moral of the story is to buy what you need in the context of a project.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: July 18, 2013, 10:40:37 pm
content: I guess that's the route I'll go then. Most of the ones listed I do use or have used, in contexts that will probably come up again. I go through a lot of 431s and 339s, for instance. I have plans for the 555s. The 381s and 74HC logic is more speculative, but I don't plan to let them go to the waste.

author: fcb
author_rank: Super Contributor
timestamp: July 18, 2013, 10:46:32 pm
content: I keep lots of these:LM7805LM317TLM393LM358TL0724016B or 4066B4017B4046B4094B74HC74ULN2803AMC340632N7002BC846B & BC856B100nF 0805'sIN40017660A10uF/35v electrolyticsLots of molex KK'sLots of 7/0.2 hookup wireLots of red/black bananasI also keep 1206 resistor books, good selection of 0805's and 1/4W resistors.

author: c4757p
author_rank: Super Contributor
timestamp: July 18, 2013, 10:49:02 pm
content: Quote from: komet on July 18, 2013, 09:41:07 pmYes.I usually try to keep a fairly comprehensive stock of generic components around. And most of them go unused. I could definitely trim the list down to just a few.Here are some of the things I do use a lot of:- 1%axialresistors. I actually have E24 (found them cheap on eBay, and believe it or not they were within tolerance). Breadboarding with SMD resistors is not a fun experience. Obviously I also have SMD for PCBs.- Forget the Zeners. I've got a pile of them - I used to use them, shoehorning the far-from-ideal voltages into whatever I was making, and then I bought a giant bag of cheap Wun Hung Lo TL431s from eBay. No, they don't quite meet the specs of "real" TL431s, but they're still better than the average Zener, have a better tempco, and combining them with those 1% resistors, you can get whatever voltage you want.- 74HC00. They'll do any basic logic (simple signal steering, cleaning up digital signals, whatever) that you want.- 74HC14. Schmitt triggers are brilliantly useful.- LM1117-ADJ.- LM393, LM358.- Your favorite DC-DC converter IC. Mine are MC34063 and NE555 (yes, 555 timer - I really do use this as asuper-cheap DC-DC). Also the associated bits and bobs (inductors, low-ESR caps, etc.)- PN2222, PN2907, 1N4148, 1N4007, BAT85S, 1N5819.Edit: I see you already mentioned some of this and I missed it. Oh well

author: smashedProton
author_rank: Frequent Contributor
timestamp: July 19, 2013, 12:49:06 am
content: It would be worth picking up one of these and characterizing all of the caps. Its always a pain to predict what value capacitors you need way in advance (especially with analog stuff).Here:http://www.goldmine-elec-products.com/prodinfo.asp?number=G3060These is also worth it too:http://www.goldmine-elec-products.com/prodinfo.asp?number=GP50http://www.goldmine-elec-products.com/prodinfo.asp?number=G15287With mostly everything else you would need, you would probably be ordering some new parts anyway to justify adding those. There is no sense in buying every kind of DAC, and then find out that all of the ones you have dont play well with your project. Also, you could just do what I did and free samples from manufacturers. They do require that you have a private email. Luckily, my school gives out private emails to its students

author: Stonent
author_rank: Super Contributor
timestamp: July 19, 2013, 01:13:17 am
content: Attiny 45/85Attiny 2313/4313Attiny 26Develop your project on an Arduino, then shrink to Attiny.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: July 19, 2013, 01:40:19 am
content: This is actually for a new lab we're setting up at work, so samples aren't an issue; that's what I'm doing for most of the expensive parts. But it's also why I'm looking at what I can get now, because if I have to buy it it's easier to put it all through accounting at one time, rather than every week or two when I realize I need some $5 part, then have to waste 20 minutes invoicing it and dealing with the accounting system...

author: Psi
author_rank: Super Contributor
timestamp: July 19, 2013, 01:46:08 am
content: Keep a few optocouplers in stock that have high current push/pull output (400mA+)They're really useful when you need a level above the typical mcu i/o power.Also general purpose "digital" isolaters are handy too, much easier than stuffing around trying to use a normal analog optocoupler for digital.

author: mrflibble
author_rank: Super Contributor
timestamp: July 19, 2013, 05:09:17 am
content: On the subject of optocouplers, any suggestions for some jellybeans?

author: Phaedrus
author_rank: Frequent Contributor
timestamp: July 19, 2013, 06:07:39 am
content: Other problem with ordering as I go is the 2 or 3 or 10 day wait for the components to arrive. I miss working in Taiwan, we had a Yellow 3C right down the street selling just about any jellybean component, and many more esoteric ones, you could ever want. Here in SoCal, the closest we get is RadioShack. The one near us is surprisingly well stocked (unlike the one in New Orleans which had three unsorted drawers of random axial resistors, caps, and switches). The one here even carries some useful ICs like 74HC parts and op amps! But their stock is spotty at best (to be charitable).So not having to wait for things to arrive is part of why I want stuff on hand. I don't want to get a really good idea, then not have the part I need and forget about it. Or be working on something semi-time critical and discover that I need to order something on-line.Plus it's not my money.There are some good recommendations here though, thanks!

author: ivan747
author_rank: Super Contributor
timestamp: July 19, 2013, 06:51:15 pm
content: I have a bunch of zeners around. They are not useful as a voltage reference. Most of the time they are not accurate enough. The good thing about them is that you can use them to clamp voltages to a level.I find a wide selection of op-amps important. By wide I mean op-amps specialised in different things. For example, some LM324s and LM358s for general use (their output goes to ground), some rail to rail CMOS op-amps to use as an ADC buffer or conditioner, maybe a some differential op-amps can help, a more ancient LM741 for this projects using ±15V you find in magazines, JFET input op-amps like the TL072 end so on.555s can be surprisingly useful as they can source and sink lots of current, you can use them as a timer, missing pulse detector, oscillator, pulse-width modulator and even as a (relatively) high power flip-flop or buffer.I find useful to have a good assortment of my favourite type of microcontroller, PICs. Various sizes, get the best one in the product family (the one with the most memory) and use the cheapest you can fit in when you are done prototyping. I keep the classic PICs, the PIC16F877A (40 pin), PIC16F873 (28 pin), PIC16F628 and PIC16F88 (18 pin) as well as an 8 pin PIC12F683 (I am missing the 16F84, though). I have some more modern ones as well, but I am not 100% certain wether these ones will live as long as the 16F88, which is in my opinion in the middle of its lifetime and shows no signs of being discontinued.I have a good assortment of logic ICs, but I rarely find a real use for them. Microcontrollers solve most issues, specially because they already have the counters, timers, oscillators, and the new ones even have glue logic all built in. The handiest logic chips are schmitt triggers, flip-flops, NAND, NOR and NOT gates.I am still finding good all-around transistors. It depends on what you need. I am sure a digital electronics person won't recommend the same FET as an audio person does. Some advise on power MOSFETS: many IRF parts like the IRF520 have multiple manufacturers, so it make them good jelly-bean power MOSFETs. For a "complementary" device (it isn't that simple with FETs) add a nine to the part, for example, the P channel version of an IRF520 is the IRF9520.Keep some random high power resistors around. Get them from old switch-mode power supplies along with opto-isolators

author: SeanB
author_rank: Super Contributor
timestamp: July 19, 2013, 07:01:58 pm
content: I have a lifetime supply of 12 and 24V 400mW zeners, so I use them as regular signal diodes at low voltage, where they are pretty good. As to other diodes, buy a whole lot of UF4007 diodes and a whole lot of UF5407 diodes. They will then be usable as both mains and low frequency rectifiers, and having a 1A and a 3A diode is a good idea in general.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: July 19, 2013, 08:02:08 pm
content: We have an infinite supply of crappy (and some decent) PC power supplies, so 1.5A and 3A diodes, bridge rectifiers 4 to 10 amps, power MOSFETs of all sorts, and Schottky diodes are in no short supply.

author: Smokey
author_rank: Super Contributor
timestamp: July 19, 2013, 08:18:04 pm
content: The thing to do is to standardize on a set of basic components you can use across multiple projects. Things like voltage regulators, processors, opamps, connectors, stuff like that. Just about every project needs some generic form of those components. Pick them based on the size of the boards you make and the technology, ie SMD vs through hole. Pick them smart the first time and keep using them where it's appropriate. That way you can buy in larger volume and have some extra stock around since you know you will use them up. Of course some stuff needs special parts, but that happens less often than just dropping in the circuit you know was working from the last design.Other than that, just take the digikey hit and wait a couple days.

author: c4757p
author_rank: Super Contributor
timestamp: July 19, 2013, 08:24:40 pm
content: Quote from: ivan747 on July 19, 2013, 06:51:15 pmNot to derail the thread, but can anyone recommend a good jellybean R2R? I'm so used to the old-style +/- 15V op amp circuits, I really don't have enough experience with the lower-voltage analog stuff like rail-to-rail amps to know what's good to stock up on.

author: hans
author_rank: Super Contributor
timestamp: July 19, 2013, 09:40:11 pm
content: At work I once ordered a whole stock of through random stuff, because for some project we didn't even have 100nF's in stock.So I ordered some basic caps (100nF, 10uF, 100uF, 16V, 35V), 9V/5V/3.3V LDO's, logic chips (AND/OR/HEX/schmitt/XOR), LM311, LM324, NE555, MAX232, MCP2551 (CAN transceiver), 16kBit EEPROM, LED's, NPN/PNP transistors (100mA), N/P MOSFETs (100mA) and crystals (16M, 20M, 18pF caps). We also have some ATTINY45's.I've ordered that 2 years ago. At first I wondered "when are you ever going to use a NE555 or a MCP2551?" Ends up there is always some project with a bricked AVR controller, or an microcontroller evaluation board that has a controller with CAN but no transceiver..After 2 years about 60% of the bags have been opened/used. MOSFETs/Transistors have run out. Although Farnell or RS delivers next day it's very very convenient to have stuff at hand. However there is always something that you don't have. If it's not a show stopper, you can keep going for a day with stock and wait for the rest the next day.We have a E24 axial book somewhere, but I rarely use it. I typically only use values 220, 330, 470, 1k, 2.2k, 10k and 100k, which are conveniently located on a 'reel' of 1000. Typically you need other values than those for voltage dividers in power supplies or opamps; in that case I try to simplify signal/power paths as much as possible.Simpler is better.For SMT we have some very large tray of often-used components in ESD safe boxes, like:Usually has 2 pins- Resistors (basic range)- Capacitors (basic range, like 18pF, 1n - 100nF 50V, 1uF/4.7uF/10uF ceramic, 47uF+ 35V aluminiums)- Inductors/ferrites- OscillatorsHas more than 2 pins- Connectors/enclosures- Voltage regulators (SMPS, LDO's)- Logic chips (OR, AND, 3-state buffers)- Diodes, for SMPS (2-3A) and signal (clamping, 3.3V zeners)- MOSFETs (N/P-channel, 100mA , maybe some high current ones)- RelaysHas a lot of complicated pins- Microcontrollers (PIC's, AVR's, LPC's)- Opamps/comperators (LM324, LM311, etc.)- 10/12 bit DAC's- EEPROMs- Interface transceivers (RS232, CAN, etc.)- 'Special' chips (ethernet transformers, 5-port switch, FT4232's, etc.)Standardizing standard components across projects saves complexity in making BOM's, keeping own stock at the office, etc. If something runs out, we usually order 50 or 100 because they will typically run out very quickly once again.I guess a list of components can vary a lot if you're into another industry. For example, we don't care much about the opamps we use, although people doing lots of precision analog work may consider different types.On the other hand, we use logic chips a lot whenever we can avoid using a microcontroller. Although an ATTINY45 is small, it requires software, which is always a pain to maintain.

author: ivan747
author_rank: Super Contributor
timestamp: July 21, 2013, 01:36:24 pm
content: Quote from: c4757p on July 19, 2013, 08:24:40 pmA jelly bean rail to rail op amp would be the LMV324 and the LMV358. The single version is the LMV321.http://www.ti.com/lit/ds/symlink/lmv358.pdfAs for the R2R, the best way I think is getting an R2R resistor network:http://www.bourns.com/data/global/pdfs/r2r.pdfIf you need the pins for it, you can either use a shift register (which can be interfaced via an SPI port, CS line to the Latch, CLK to the clock, and MOSI to the data in. Just mind the polarity of everything) or an I2C bus I/O expander.You can buffer it with an op-amp.In the end, this is simpler, smaller, and maybe even cheaper:http://ww1.microchip.com/downloads/en/DeviceDoc/22272C.pdfShould be nice to have some stored around. The problem is they don't have DIP version, so you need a little adapter board. Solder the ones you want to stock to the adapter board, and you can use them with a breadboard.

author: c4757p
author_rank: Super Contributor
timestamp: July 21, 2013, 06:29:53 pm
content: Oops, forgot about this thread! "R2R" was Crappy Touchscreen Keyboard for "rail-to-rail"! I don't think I'd ever bother with a discrete R-2R DAC.Thank you for the suggestions