newer IC's Max1674/1675/1676

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joeparker54
 
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Joined: Sat Sep 01, 2007 7:23 pm

newer IC's Max1674/1675/1676

Post by joeparker54 »

while on Maxim/Dallas' website, i found that they recently introduced an updated model of the max756/757 chips. they are the Max1674,1675,and 1676. According to Maxim, they are more efficient and don't require an external Schottky diode and have preset, selectable 3.3/5V output.
The info page can be found here: http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1878[/url]

I guess what i'm wondering is if i use the 1675, would all external components (besides diode) be the same values, and would any wiring change?
Also, would the added complexity of the 10 pin max1676 be worthwile for its anti-ringing feature?
Any answers would be appreciated, as i've got free samples (GOTTA LOVE MAXIM FOR THIS!) of all of these chips along with the older max756 on their way in the mail, and i'm just wondering which one someone who's more experienced would go with.

after looking at the data sheets, I think i'd be inclined to use the max1675 in my charger that i'm building (same circuit as mintyboost, but with a bit more rugged container), mainly because its still an 8 pin, with pretty much the same pin layout, but it has a 500 mA current limit, which is plenty enough for me.

adafruit
 
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Joined: Thu Apr 06, 2006 4:21 pm

Post by adafruit »

its a umax package, i hope you have a high quality soldering setup for that ;)

joeparker54
 
Posts: 6
Joined: Sat Sep 01, 2007 7:23 pm

very good point on umax package

Post by joeparker54 »

hmmm... maybe i'll just use the 756, as my soldering skills are garbage, then again, we'll see how it goes. I could do a practice run first. As i said, i loaded up my sample cart with 2 of every single dc-dc step-up they had.

Thanks for the feedback!

joeparker54
 
Posts: 6
Joined: Sat Sep 01, 2007 7:23 pm

Wow, they sure are tiny

Post by joeparker54 »

I just received the samples in the mail yesterday, and man, are those suckers tiny compared to the 756 (one barely takes up half of my pinky fingernail).
If they were twice as big, I still wouldn't be able to solder them, much less make a board by hand for it. Good thing i got the 756's too!
The inductors were by far the biggest pain to find. After finally breaking down and ordering off of Mouser, I came across CoilCraft, who gives free samples. I can only hope everything goes well from here...

TheDon125
 
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Joined: Tue Jan 09, 2007 9:58 pm

Post by TheDon125 »

They are tiny, but with patience, they can be hand soldered with even a cheap iron. Even the board can be made with the toner transfer method.

My attempt at using the MAX1654

I will note that while board v1 does output 5V, I have not tested it on anything that uses the data lines, so I dunno if it will work with an iPod, but it works just fine for my Gameboy Advance and Nintendo DS. As for board v2, completely untested, but the polarities should be correct that time around. I would also like to note that I lost no chips due to improper soldering, but I did burn three when I forgot to add resistance, and then checked their output with my multimeter...instantly fried. One last note, if you bridge two pins that shouldn't be bridged, an exacto knife is the perfect width to cut solder between pins if need be.

coolcat
 
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Joined: Mon Sep 10, 2007 12:58 am

Post by coolcat »

I made a charger using the MAX1674.

Learnt a few things along the way that should not drill hole close to the chip, it messes up soldering close to chip.


Need:

1. Desoldering wick.
2. Rosin based flux (bought mine from Fry's). Very useful to remove excess solder and remove bridged joins.
3. magnifying glass (very essential, hard to see bridged connections otherwise).

I am still revising the schematic/board. Hope to get this done and post this.

The cool thing is that this has low battery indication etc on the PCB.

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