FREE DC-DC CONVERTERS!!!

[timmeh87]

ok. i mentioned this somewhere else yesterday, but now i have confirmed it, and i am here to let you all know how to get FREE dc-dc converters shipped to your front door! for free!!

you will need the following things:

- the internet
- a web browser
- an "official" sounding email address. @hotmail or @gmail will not do (well actually it MIGHT but youre really reducing your chances). you need something like @stanford or @microsoft or something of that nature. i just use my university email account, @mcmaster. college will do just as fine. or get your parents to let you use their work address.
- a name
- a phone number
- an address

that list was mostly made up as a joke, conveying how easy it is to get these things. i slipped one important point in there though. guess which one

ok. so. we will be getting our dc-dc converters from texas instruments. feel free to look around their site:

www.ti.com

i would guess that 90% of people here need the dc-dc for their 3.3v line. (am i right when i assume the 12v doesent need a reg if you give it 7.6 off a battery pack?). so, i have done all the searching for you. the part you need is the PT78HT233H. (edit: in the months since i made this post, we have found better converters, check the wiki) the last letter can be several different things. it dosent really matter.

some features as listed at the site:

High Efficiency: Up to 90%
Wide Input Range
Self-Contained Inductor
Short-Circuit Protection
Over-Temperature Protection
Fast Transient Response

is your mouth watering yet? the product page and datasheet, respectively are

http://focus.ti.com/docs/prod/folders/p ... ht233.html
http://www-s.ti.com/sc/ds/pt78ht233.pdf

note that it requires at least 9v on the input side. (and is most efficient at that voltage too). if you cant make a 10 volt battery pack, then look for another product. they probably have it. they just might not offer free samples for it.

UPDATE: a lot of people are saying that these converters will run off 7.2v ok.

on the main product page, search around for a bit. you will come across a link that says "request free samples". see where this is going?

im assuming you have clicked it by now.

from there on in, you will have to make a new account. you will be sent a confrimation email, and then you will have to confirm your email...then you will be sent ANOTHER confirmation email. that part had me confused for like 10 minutes.

when you make your account, use REAL INFORMATION. this is a legitamate company. dont worry about spam or identity theft or anything.

i cant really guide you though this since i already did it. and i cant do it again. and i forget. but anyone smart enough to know how to hook up a dc-dc converter should be able to figure it out.

at the end of the day, you will have a "shopping cart" with the part you requested in it. you can only get one of these converters at a time, BUT, they come in 3 very similar "packages", and you can get one of each if you need to. while youre at it, browse their products for anything else that looks useful. they have more dc-dc's than you ever imagined, plus lots of other stuff.

BUT - dont abuse the system!!! dont order parts you dont need just because they are free. you WILL eventually be "cut off" if you start making tons of sample orders but never actaully buy anything.

when they ask you what shipping method you want, choose fed-ex priority... its FREE!

i ordered a dc-dc at 1:30 this afternoon, and according to my tracking number, it was shipped out by 1:45. im supposed to get it by 5pm TOMORROW.

and i live in <b>CANADA</b>

and that concludes the guide to free dc-dc.

but one more side note:

i have one of their dc-dc's right now that i got from school today. the only difference is that it is rated for 1 amp MAX. according to the guy who i talked to, this means it CANNOT outpute more than 1 amp. i have a 10 volt line hooked up to the 12 in the '64, and the dc-dc is hooked up to the same 10, and ouputting ~3.28. i have all the caps set up right, and even some more caps for good measure (two 100 micro electrolytics from 3.3 to ground, and a 47 micro ceramic from the 10 to ground).

when powered on, the light turns on, and the screen flickers repeatedly, as if it is trying to start but cant. could this be beacuse it just cant get by on 1 amp? ill tell you in a day or so i guess if the 2 amp model works.

[nos_slived]

If I remember correctly, the 3.3V line draws about 1.3A-1.5A, so you either need a higher output regulator or 2 in parallel(which should increase efficiency anyways). I'm going to see if I can get my electronics teacher to let me use the school's address, because Fed-Ex always delivers when nobody's home here. I'll just use my webmaster email for the school's site when I order the samples. A lot of sites offer free samples(MAXIM, TI, National), you just need to look around.

BTW, you are Canadian, therefore you rock!

[marshallh]

Awesome! I don't know but the link you gave me showed 2 amp regulators. I'll try those out. I got a 5v one for my SNES too

I thought TI was very strict on samples but I was wrong!

[x24]

yup, canada rocks *makes wooting sound in the middle of accounting class*

I'm still slowly gathering pieces for an n64 portable.. would this be useful?? if it is, I looked at the specs page and there are many places where it says "free samples" which ones is the piece id need.. Ive already registered and everything..

[timmeh87]

@nos - you mean 1.3A - 1.5A right?

@marshall- yeah, the 1A one i got was just lying around. i ordered the 2A one yesterday though. hopefully ill get it today and tell you guys if it works.

@ x24 you should see 3 "get free samples" links right? if you go into the detailed specs, you will see that they are all almost identical. its just the size and shape that differs a litle bit. pick any one, they all do the same thing, and are all about the same size.

and if anyone is wondering about the size, they are about an inch square (thats 2.54 cm) and 1/3 of an inch (8mm) high.

[timmeh87]

well i hear theres a dislike of double posts around here, but this is sorta completely separate from my last one here so im making it a new one

i got my 2A dc-dc in the mail today. it came in a box the size of the newest harry potter book. what a waste of packaging.

anyhow, i swapped it into my circuit with the 1A one and.... nothing happened. or more specifically, the same screen-flickering-but-nothing-else happened.

then i thought back in time to grade 11. i had made an elecric motor for physics class, and i had used the same power supply i was using for the nintendo. whenever the armatrue flew out of its hodler thingy and stick to the field coils, the two electromagnets vibrated like they were having magnet sex on crack.

and there i found my soloution - the power supply i was using (which was from a tape backup circa 1980) was WAAAY too noisy. i think it might actually just be doing a straigt up inversion of the ac, giving out dc thats drops to zero 60 times per second.

luckily, i had brought home three li-ion cells with me from school. after hooking them up in series, and measuring the voltage at a juicy 11.8, I hooked the '64 up to the tv. and it ran like a dream.

anyhow. right now i gotta go to school again for the weekly solarcar meeting. ill update this post later with a circuit diagram and such.

but the point is, the dc-dc's work. well.

[nos_slived]

@nos - you mean 1.3A - 1.5A right?

Yea, sorry about that. I made that post while I was watching the Canucks game last night, so I wasn't really thinking.

I asked my teacher, and he said that I can have the samples delivered to the school with his name, so I just created a TI account.

BTW, the time offset on this new server is making me mad.

[daguuy]

i've heard that it take 1.3 amps from some people but .8 amps from others. is it the jumper/expansion packs that make that fifference?

[nos_slived]

I think I remember some people saying that the expansion pak takes a lot of power, but ultimately it comes down to the game. The better games usually required more power, because the N64 has to work that much harder.

[MaDnEsS]

I DONT TRUST FREE OFFERS! i liked your old avatar daguuy

[sydney075]

Well I ordered a sample if it is everything it says that it is then my batteries will thank me for it. There is still a slight problem of regulating the 9.6v battery pack (8 nimh aa's) down enough for the lcd to not fry but, I guess I can use my lm317 setup to knock it down seeing as it isn't much of a drop the voltage waste should be minimal. I look forward to getting my converter thanks for the heads up just hope it fixes my voltage problem.

Side not I ordered some 3mm ultra bright leds (white) yesterday 25 for $5.01 yay but, they are comming from hong kong with an estimate ship time of 9 days oh well once they get here I should have all the parts to finish my unit.

[daguuy]

i liked your old avatar daguuy

yeah i can't decide on one: should i use this one or my old one?

[S q u e e !]

Old. That's just like goodie's avatar.

Anyways, I just tried this, and it says it should be delivered on Saturday. I sure hope it works!

[timmeh87]

ok.. here is a whole buncha pictures i took, with descriptions. sorry about the quality. i did it quickly and with a crappy webcam.

https://muss.cis.mcmaster.ca/~bernast/

and this is the circuit that i have:

<img src="https://muss.cis.mcmaster.ca/~bernast/img/diagram.gif">

its as simple as that folks. i said 9-15v assuming that the system could handle 15 volts. i think it can, right? anyhow. just do what you know is right.

the 10micro is tantalium, the 100 is electrolytic. the data sheet said specifically to put an electrolytic where the electrolitic is, and a ceramic where the tantalium is.

notice that the tantalium is a filter for both the dc-dc and the 12v line. it might benefit from a bit of a higer value due to its dual role?
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i was also talking to a 4th year electrical engineer on the solarcar team. he said i should build my case out of carbon fiber. of course, we make parts of our car out of it so we are all set up to do such a thing. that would be sooo cool. im excited

he also said that if i build a proper protection circuit, he will give me what he CLAIMS is a 10Ah li-ion battery. he suggested i run the 3.3v line off that unregulated, and use a step UP dc-dc for the 12v line.

does anyone know if the 3.3v will be ok with 3.0 - 3.8 volts?

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oh and squee - mine said saturday too. but check your tracking number. if you ordered before like 5pm i bet its already been shipped out.

[nos_slived]

Yes, the N64 can handle 15V(up to about 35V actually), however if you use a PSone screen, you will need to get the voltage down to 7.2V-8.4V going into it.

If you have a v1 board(NUS-001 to NUS-007 I believe), the 3.3V line an handle a large range of voltages, but any other boards have to be pretty close to 3.3V(I think sound craps out below 3.1V, and the board fries with anything more than about 3.5V).

Does anybody know if you can check on the orders that you placed on TI's site? I ordered the samples, but I never received the email(and no, I don't have a spam/bulk folder).