FS: CRT3350A 3.3V and 5V breadboard power supply module - Page 1
Forum section: electronics / general

author: bloguetronica
author_rank: Frequent Contributor
timestamp: October 26, 2017, 12:48:38 pm
content: Hi,To whom might concern, I have 4 of these modules for same on eBay:https://www.ebay.com/itm/152733789752Each module is fore sale at$48.00$40.00. These modules are indeed more expensive than the comparable Chinese ones (that only can supply 250mA at best), but they use high quality components and they can supply up to 980mA each rail (3.3V and 5V). They are fully configurable to your needs and fit on most breadboards. The boards use high frequency DC-DC converters, that are very efficient and have relatively low noise.Specs:- 3.3V and 5V regulated output voltages;- 980 mA maximum current (each rail);- Operation guaranteed with supply voltages between 7V and 16V;- Over-current and reversed polarity protection, plus added protection against spikes on the outputs;- Uses Texas Instruments TPS62152 and TPS62153 regulators for better precision and efficiency;- Fully configurable via jumpers.Recommended power supplies (for full capacity loads):- 9V 1.5A or 12V 1A (linear or switched mode).Please, reply to this thread or feel free to PM me if you have any questions.Kind regards, Samuel Lourenço

author: bloguetronica
author_rank: Frequent Contributor
timestamp: November 04, 2017, 11:37:46 am
content: Hi all,I've decided to make agreater than 10%discount for the forum users.$40$38 for the board + $8 for the shipping. Any bigger of a discount and I don't have margin.Anyone? Consider that this little board can deliver 3,3V 1A and 5V 1A at the same time!Interested? Contact me via PM. I only accept PayPal.Kind regards, Samuel Lourenço

author: sn4k3
author_rank: Frequent Contributor
timestamp: November 04, 2017, 04:47:11 pm
content: I think that is very overpriced for the product...Even if quality components they are dirty cheap, your board didn't use so many passives and can be built as single side PCB.You can easy do 1A with regular regulators or cheap bucks converts. For breadboard i think almost no one care about effeciency and lets say the bredboard is not a stable environment. And lets say 1A is not that much either.The chinesse boards can output more than 250mA, at least 500mAh, they are using the linear regulators, have a power switch and also can be powered from USB which is very convenient, and your board miss all that.For the price justify you have to find better approach, maybe support voltage selection ( 3.3v, 5v, 12v(header), 19v(header), usb, switch )Or even make a cheap board that take 5V 4A input from a power supply brick, that way you already have the stable and protected 5V and after that you only have to take care of 3.3v and regulate for example using the LM1770TMF, that can output 4A Max at 3.3V, simple, easy and lot more power.I like to see people releasing products their own, special if that don't come from china, i understand that you want to make profit and thats ok. But for the price people can buy a very good power supply brick and feed them to breadboard.When ordering PCB depending on fab you have a minimum quantity that way you want to sell the spares and stay with one or two units for you, but instead of tring to squeeze the best profit out of that i think is more important to give a fair price, even if you lose some money people will try your products and if they are good and like maybe in future you can build more stuff and sell with good profit.Regards from Portugal

author: bloguetronica
author_rank: Frequent Contributor
timestamp: November 04, 2017, 10:30:01 pm
content: Overpriced you say. The BOM alone, without the PCBs, costs around $20. The components are not dirt cheap. Passives are the not most expensive, they are the cheapest components. The DC-DC converters and the inductors are what costs the most.And then you say that the Chinese boards output more that 250mA. I assume you are talking over your experience. Well, me too. I actually bought one of those black boards with yellow jumpers, based on the LM1117 knockoffs. One is toasted, because one can't expect to extract even 250mA from those tiny LDOs."When ordering PCB depending on fab you have a minimum quantity that way you want to sell the spares and stay with one or two units for you, but instead of tring to squeeze the best profit out of that i think is more important to give a fair price, even if you lose some money people will try your products and if they are good and like maybe in future you can build more stuff and sell with good profit."Gee, what a great advice, or perhaps I'm just being sarcastic. I hope you don't expect me to work for free. Oh, I just give away the boards then!Update: See the BOM attached.

author: sn4k3
author_rank: Frequent Contributor
timestamp: November 04, 2017, 11:08:28 pm
content: Quote from: bloguetronica on November 04, 2017, 10:30:01 pmI know the BOM for you alone will be a higher than bulk source or buy at china, thats a fact, not arguing that.About china modules the way you said "(that only can supply 250mA at best)" is like put every other modules on same bag, look at your word"at best". You assuming all chinese modules would be crap and only deliver 250mAhat best! No way to deliver 300mAh because output 250mAh will be a luck at best... That can also be true if power from PC USB limited to 500mAh. Of course there will better modules than others at same price level but is not fair to judge just based on one or more modules that you got that doesn't meet the specs. That is just marketing from you because all know the chinesse module will be cheaper and if worst or not people most of the time don't care, they trend to decide based on other criterious which is budget, application, use, or others. So you are comparing Apples to Oranges because your bord is designed with 1A spec and chinese boards don't. But i like the way you have put the specs with the real ICs you use on it.I don't expect you to work for free or give away the boards but is this even your work? Make and sell modules? Because to me seens more a module that you build and order for yourself and want to sell the remaining from the min. order quantity or to just pay out the modules.I only have and use quality equipmenet on my lab and i like to pay for it, price is not the problem itself, but it need to justify and worth the value. It's all about the correct price for the things.I'm not against, discourage or telling you what to do, i'm just giving my opinion and i wish all the best for you.

author: bloguetronica
author_rank: Frequent Contributor
timestamp: November 05, 2017, 09:33:22 am
content: Well, your posts are full of wrong assumptions, I should say. I don't know where to start. And, why bother.

author: MK14
author_rank: Super Contributor
timestamp: November 05, 2017, 01:30:12 pm
content: Quote from: bloguetronica on November 05, 2017, 09:33:22 amThere is a (maximum) price for things, which people can afford/want/will pay. If you design and build something, which after adding on all your costs and profit etc, is greater than that maximum price. You will usually have a very hard time trying to sell it.Example:Maybe I could hand build a PC for you, and build it out of various small parts, at the component level, and (including my huge time to make it, and hence massive labour charges). I may want £10,000 for it, including profit.How many of these PCs do you think I would sell on these forums, if an identical/equivalent PC, was around £500 from a reputable supplier ?

author: mariush
author_rank: Super Contributor
timestamp: November 05, 2017, 02:35:35 pm
content: Quote from: bloguetronica on November 04, 2017, 10:30:01 pmJust going through your listNichicon 100uF 25v polymer capacitor at 3 euro - they're 1.55 euro if you buy 100 on Farnell , or 2$ each if you buy 100 onDigikey(add vat and shipping is free is you buy enough stuff)But you can buy something with close enough specs from other stores, like Samxon (X-Con) 100uF 25v for 0.2 euro each if you buy 100 :https://www.tme.eu/en/details/ulg100_25/polymer-capacitors/x-con/ulg107m1ef1arrx0cr/It's still a polymer capacitor, still overkill for such a project.Then you have 1210 22uF 10v x5r for 0.8 euro each, and 1210 10uF 25v ceramics for 0.4 euro eachI sincerely doubt you MUST have exactly 22 uF or exactly 10uF, that things would fail otherwise. You also have room on the circuit board to connect two ceramic capacitors in parallel so I don't know, maybe you could have used two 10uF or two 15uF in parallel to get capacitance close enough to 22uFAnd, instead of having two separate BOM components, just buy only 25v or higher rated ceramics instead of one 25v rated and one 10v rated. If you have 4 capacitors per board, you get better prices by ordering just one component in bigger quantity.For example0.3 UK Pounds per 50pcs on Farnell : C2012X5R1E156M125AC - SMD Multilayer Ceramic Capacitor, 0805 [2012 Metric], 15 µF, 25 V, ± 20%, X5R, C Serieshttp://uk.farnell.com/tdk/c2012x5r1e156m125ac/capacitor-mlcc-x5r-15uf-25v-0805/dp/2526258and 10uF ceramics are all over the place, x5r, x7r, 25v rated, and so on ...ex0.048 euro each in 100pcs : Samsung CL32B106KAJNNNE Capacitor: ceramic; MLCC; 10uF; 25V; X7R; ±10%; SMD; 1210 :https://www.tme.eu/en/details/cl32b106kajnnne/1210-mlcc-smd-capacitors/samsung/But even if you have to go with exactly 22uF, you have for example0.162 euro each in 100pcs : SAMSUNG CL32B226KAJNNNE Capacitor: ceramic; 22uF; 25V; X7R; ±10%; SMD; 1210 :https://www.tme.eu/en/details/cl32b226kajnnne/1210-mlcc-smd-capacitors/samsung/...and 0.5 euro for a diode ...what's wrong with0.163 euro per 100pcs : NEXPERIA PMEG4050EP,115 Diode: Schottky rectifying; SMD; 40V; 5A; SOD128 :https://www.tme.eu/en/details/pmeg4050ep.115/smd-schottky-diodes/nexperia/pmeg4050ep115/0.166 euro per 100pcs : ON SEMICONDUCTOR MBRS540T3G Diode: Schottky rectifying; SMD; 40V; 5A; SMC; Package: reel, tape :https://www.tme.eu/en/details/mbrs540t3g/smd-schottky-diodes/on-semiconductor/Seriously, a stupid led is 0.116 euro ? you buy 100 for 0.05 euro each or even lower0.032 euro / 50pcs , 0.02548 euro per 250pcs : OPTOSUPPLY OSR51206C1E LED; SMD; 1206; red; 100-120mcd; 3.2x1.6x0.8mm; 120°; 1.8÷2.5V; 20mA :https://www.tme.eu/en/details/osr51206c1e/smd-colour-leds/optosupply/The switching converter is nothing special except it runs at 2.5 mhz ... lower that down to 1 mhz or 1.5 mhz and you find plenty cheap regulators and the inductors would still be super small and cheap.... yeah, price is HUGE for such a simple product. If you want to sell, you need better prices dude.

author: bloguetronica
author_rank: Frequent Contributor
timestamp: November 05, 2017, 05:46:54 pm
content: Well, it so happens I can't lower the price. Either you accept it or you don't, and that is the way it is. I'm not in a hurry.I also can't buy components in hundreds, as that is too expensive just to make a couple of boards. I would expend 500€ at least on cheapo and potentially useless components, and I can't afford that.Anyway, revised the price taking out the eBay fee of 10% and adding the PayPal fee. The discount is no longer greater than 10% because the eBay price was revised and reduced as well. That is my bottom price.

author: Ysjoelfir
author_rank: Frequent Contributor
timestamp: November 06, 2017, 04:45:52 pm
content: Well, let me say it that way: I am definitely willing to pay good money for a good product. BUT there are other things: If someone is... let me say if in a friendly way... so confident about his product that every friendly critic is being attacked as if the person shot you in the knee, it is not very likely that I will buy the product. I instantly imagine someone bouncing around in anger telling me to bugger off if I have a problem with his product. Someone, that doesn't accept any good advice. So.. why should I give this person my money if he doesn't appreciate me as a potential customer?And by the way: Just calculate the prices mariush gave you. If you buy 100 of the parts, you are at the price for ~2 to 3 of the products build with your prices...

author: bloguetronica
author_rank: Frequent Contributor
timestamp: November 06, 2017, 06:01:26 pm
content: Well, I didn't knew about TME, now I know and decided to try them. I will also go for the more cheaper Samsung caps, and I'm considering only buying Kemet polymer caps for now on. They are good and almost as cheap as those CapXon ones. So, advice taken, and I do appreciate. But I can't change the BOM of a project that is already built. Thus, either I can:- Keep the price and hope to sell the product;- Keep the product. Extra boards are handy.Option 3, that requires to assume the loss and sell the product cheaper than what it cost is not viable for me, unless it starts to rotten (I would not sell them, then, but give them away). Redoing this project is viable even less.And don't forget that mariush didn't put all the items in the BOM. And didn't include VAT nor shipping (TME takes about 7€), nor selling fees of whatever. It is those hidden costs that people wont look at. Taxes in Portugal are expensive (23% VAT). Don't know about Romania. There is also the currency conversion issue.About confidence. Well, I'm not confident in my product. It might have its flaws. But at least it was not because I skipped quality. I would never use standard caps on a SMPS that requires low ESR ones. So, it is a simple board that requires poly caps. About "It's still a polymer capacitor, still overkill for such a project.", that is only one example of a wrong assumption. There are many others written here and there. For instance, I don't do boards for a living, but I do expect return within what's reasonable. I do not, therefore, try to compete with commercial projects that are made by the thousands and cut corners, even in salaries (not that this is my salary, again, another wrong assumption).Sorry for my rant. I did shot myself in the knee. I guess nobody likes a stranger "break into their house" and tell them what to do, even if the intentions are good. That was how I felt.

author: bloguetronica
author_rank: Frequent Contributor
timestamp: November 06, 2017, 07:35:27 pm
content: Did a quote on Mouser, assuming I wanted to do 100 boards. Certain components were replaced for cheaper ones. Others were canceled. Here is the result:- 77-VJ0805Y332KXXCBC x 600 = 83,40€ (400 are to replace those nastily expensive 22u 10V caps);- 77-VJ0805Y332KXXCBC x 200 = 10,40 €;- 512-FSV540 x 100= 25,00 € (aprox. same price as ON/NXP diodes);- 604-APT2012EC x 200 = 11,60 € (almost as cheap as those opto LEDs);- 863-MMSD4148T1G x 200 = 10.00€ (those are needed too);- 576-2920L185 x 100 = 45,30€ (expensive, but proven);- 595-TPS62152RGTR x 100 = 121,00€ (oh well, if I wish to use another, better to redo whole project);- 595-TPS62153RGTR x 100 = 121,00€ (same applies);- 994-XFL3012-222MEB x 200 = 208,00€ (meeeeeb, what can I do?)- 80-A750KK107M1EAAE40 x 100 = 19,20€ (to replace the expensive poly caps)The grand total is 654,90€, and there are many components missing, like headers, connectors and resistors, and I don't know what more. Then there is the VAT. And then there are the boards. Perhaps I could do 10€ per board if I had ordered 100 boards, without profit. Still couldn't compete. TME prices are not that much cheaper and the availability is scarce. Even by choosing cheap components I still have to pay €€€, instead of €€. Hope I prove my point and I don't want to look like a greedy bastard. I do understand that life costs.In the end, admittedly these boards are expensive, but I can't do cheaper.

author: sn4k3
author_rank: Frequent Contributor
timestamp: November 06, 2017, 08:06:27 pm
content: A good exercice you can do is think like you was the customer and not the seller:Q:Would i buy this product? (Knowing all other avaliable offers, including the cheap china modules and your requirements)A:If your anwser is no think why you woun't buy it.A:If your anwser is yes then take the board and use it. After some time being used put the board on your hand look at it and try to fell if it worth the buy or not.Quote from: bloguetronica on November 06, 2017, 06:01:26 pmI think no one here is telling you what to do, they are only advices and opinions. It's up to you to like, dislike, listen, follow or whatever but you are not obligated to nothing.If people comment your post and note that can take some time given the post size, analysing, read, search, reply etc, is because they are trying to help you somehow, ratter than fell like you do, i think you should look this from a different prespective and thank people who invest their time trying to help or at lest contribute with something.As i told before, nothing of that is to discourage you, instead that people are trying to help you found a better path for both you and your clients (Win/Win) situation.

author: bloguetronica
author_rank: Frequent Contributor
timestamp: November 06, 2017, 08:56:52 pm
content: Well, that is a good exercise. I got to admit that budget was not one of my concerns when I created this project. I was more concerned on replacing a board that used linear regulators, but with much better efficiency. So, low noise and higher frequency was a requirement (in order to provide the same, or close enough, power quality that LDOs supply). It is very difficult to aim to that niche marked, especially when that kind of quality is needed. So, indeed this fails to be a commercial product. Demand is already well satisfied, I guess.

author: sn4k3
author_rank: Frequent Contributor
timestamp: November 06, 2017, 09:53:29 pm
content: Quote from: bloguetronica on November 06, 2017, 08:56:52 pmThats the pointWhen you designed the product your main goal was your requirement, your need, performance and quality, not the market itself, and that's why it failed to be a commercial product. Even big company need many revisions of the board to make it work and profitable. You can check some of your equipment, they will have some revisions, where the first ones just failed in some aspect and that caused of course a lost of money and time. See what happened with S7 Note (Correct me if that not the right model), because a bad design or lack of testing milions was lost in the pit, but they assumed the error and refund people, they tried hard to keep the brand name reputation. That why people who used and use samsung didn't quit and change to another brand, because they fell somehow can trust the brand and thier money will never be wasted.People learn best with their errors and try to improve, but i wouldn't call your project a error, since it accomplish your goal and serve you well (ie. meet all your requirements).In the end you should be happy to create your custom full functional product from start and i think more people should do it, instead of buy everything ready even if expensiver without knowing how things are made (Knowledge is priceless), even most of the people this days don't value the things because they are easy and cheap to buy, but before something reach their hand someone had to work very hard or it entire life. Is grateful to see people use your inventions, now think if millions use your product...I'm also sure people will benefit from your projects and your share, in a way to improve their builds or just by following your implementation to another project.btw i think you should share and show your electronic projects from your blog here, nothing wrong about it and you will recieve lot more input. I found them nice and usefullRegards

author: bloguetronica
author_rank: Frequent Contributor
timestamp: November 06, 2017, 10:46:04 pm
content: I never thought you read my blog. Few people do. Thanks!I appreciate your positive feedback, and I'm glad you find it interesting. Hearing something like this is priceless and makes all the effort worth.Kind regards, Samuel Lourenço

author: mariush
author_rank: Super Contributor
timestamp: November 07, 2017, 02:16:03 am
content: Quote from: bloguetronica on November 06, 2017, 06:01:26 pmTME.eu doesn't sell Capxon capacitors. The ones i suggested are by the X-Con brand, which is the brand used by Samxon ( Man Yue Technology Group whatever) for their polymer capacitors :http://www.manyue.com/brands.htmlIt's a brand with good reputation, right below the brand name "Japanese" polymer capacitors and used on lots of motherboards and video cards without any problems.The 100uF 25v polymer capacitors I linked to were very low ESR, just not as low as those Nichicon RNS capacitors you had in the BOM. For example, the Nichicon RNS have 15 mOhm ESR and up to 4.5A current ripple while the ones I suggested have <= 40 mOhm ESR and 2.5A current ripple.My argument was that for an input capacitor, it was good enough. Your board expects to be powered from a 9v or 12v adapter which should already be regulated enough and have some capacitance on the output, so the lower current ripple of 2.5A wouldn't be an issue, and the slightly higher ESR value would also not be a big deal.Indeed, looking at datasheet for the voltage regulator used, there's no specific recommendation for maximum ESR accepted, only that ceramic capacitors should be used for their low ESR and that 10uF would be adequate.I don't know about Kemet polymer or ceramic capacitors, I didn't research them as much and I don't see them in lots of commercial products (which I don't know what it tells me.. either they're too expensive to be bought in volume, or they're not made in big enough volume, or maybe they're used only in industrial parts I don't see as often, no clue) so I'm more comfortable with X-Con (Samxon) or other brands I see often in commercial products.With the ceramic capacitors you'll have to pay more attention to voltage bias curves when choosing what to use. Not all X5R and X7R are the same, and some have much higher variation in capacitance with voltage. The Samsung ones TME sells are very cheap, and may not be the best for your particular regulators. Could be TDK ones or Murata or some other slightly more expensive brand would be better.... but the point was that it's just silly to buy 2 pieces of a ceramic capacitor, just buy 50 or 100 to get better prices. Even if you only need 10, just buy 50 and sell packs on 10 or 25 on eBay for the price of postage and ebay fees and some small profit.Quote from: bloguetronica on November 06, 2017, 06:01:26 pmIt's 19% or 20% here in Romania, so it's not that big of a difference. Shipping was 17 RON last time I ordered from them (which is around 3.7 euro)And by the way... you have other options as well, for example Digikey in US. For big enough orders (I think it's 200$ or something like that now at least for Romania), the shipping is free.Yes, you do pay the VAT when the package arrives in country and maybe you also pay the customs fees which could be between 1 and 3% (usually less than what shipping would cost) but - i may be wrong about this - EU recently removed the customs fees for electronics and electronic components and stuff like that , to be more competitive with China and other countries.Again, I don't know if this is actually in effect or if it actually applies on to retail electronics (like game consoles, TVs etc) and not components / parts but either way the customs fees were small anyway.You may get a much better price by ordering in volume (50-100pcs) that it would be worth even paying those customs fees and still end up cheaper than buying from Mouser or some local store.Quote from: bloguetronica on November 06, 2017, 06:01:26 pmSee my explanation above. By no means was I suggesting a sub-par component, I'm also a stickler for quality components.

author: bloguetronica
author_rank: Frequent Contributor
timestamp: November 07, 2017, 01:33:34 pm
content: Quote from: mariush on November 07, 2017, 02:16:03 amSorry about my confusion. Confused the brands.Quote from: mariush on November 07, 2017, 02:16:03 amThe ripple current is not necessarily caused by the ripple on the adapter itself. In this case, it is caused by the switching regulators downstream. Thus, it is best to use low ESR capacitors. I could, of course, use a normal electrolytic with, say 100 mOhms, and could get away with it, assuming that my ripple current is 40% of my output current. It wouldn't last as much, since that life expectation for normal electrolytics doubles for each 10ºC lower than the maximum rated. I should say that I even used polymer caps on a project that used an LDO. It was an expensive project that I though it didn't expensive deserve to fail earlier (in 10 years time), in my opinion, and the cost would increase just 2€ for a 120€ BOM project (that probably will not sell).Quote from: mariush on November 07, 2017, 02:16:03 amI think they are OK, and the price is comparable to those from X-Con. Never tried, but they are among the first tier for some hobbyists. Thus, they are well rated, so it seems. One advantage though, they are smaller than those form Nichicon and Panasonic.Quote from: mariush on November 07, 2017, 02:16:03 amI would be worried about using them in HF filters, but then again I normally choose NP0 5% for that. The switching regulators in question are quite forgiving about capacitance variations at their outputs. But yes, it is better to be careful when choosing between brands, and with preference for high quantities. The price of the 22u 10V Murata caps is gargantuan when compared to the Samsung ones, also X5R and 10% rated.

author: ez24
author_rank: Super Contributor
timestamp: November 07, 2017, 11:48:14 pm
content: Quote from: bloguetronica on November 05, 2017, 05:46:54 pmSeems to me that you are getting a good education here. Many spend big money for their education. Keep up the good work.Consider the money you lose as part of your education.

author: bloguetronica
author_rank: Frequent Contributor
timestamp: November 08, 2017, 11:15:42 am
content: Good point, and very well observed. However, it doesn't replace a degree, although nowadays this is becoming is a less important factor.