Chip found... now testing 51k resistor in place of 49.9k

[kevla]

Another Edit!

After 4 weeks my PCB's have arrived..
Still wishing I bought the kits

Also - no wonder the chinese economy is booming, it took less than 2 weeks for most of the components to arrive from the far east and twice that long for the tins and PCB's...I wont be ordering from America again unless I really need to...

anyway! on the i-charging page it says to use higher resistors, now lower. I'll be soldeing it all tonight so will update ASAP...


--------------
Edit!

Linear sent two samples so now testing 51k resistor instead of 49.9k....

Will update when pcb's arrive

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Old post...

Hello,

I do not want to order £5000 from Linear and some dude on ebay is selling them for £10, very expensive.. and he only has one.

I would like 5... does anyone have these for sale?

Thank you!

[Shadowww]

You can request samples from them, I am not sure but I think you could get 5 chips that way.

[kevla]

I have tried that (thanks) but not sure I will get any, others here have not had much luck...

[scottinnh]

It USED to be true that Linear had a horrible website, and wouldn't sell direct to hobbyists... not true anymore.

Go here: http://www.linear.com/product/LT1302#orderinfo
Then right under that table, click "Buy Now".
... it's just $4 in QTY 1.

What sucks is Linear's shipping cost more than the chip ... and DigiKey won't stock the 1302 in DIP packaging... Linear does not sell to Mouser... and neither AdaFruit nor SparkFun want to carry the raw chip (I've asked both of their Customer Support departments to carry it).


So yeah, getting the 1302 is inconvenient. Buy extra to deflate your shipping, then buy some extra MintyBoost PCBs, and you'll know what I gave my friends for the holidays a couple of years ago

You can try pinging AdaFruit and SF to carry it, maybe if they keep hearing it one of them will give in. There's still shipping, but at least it can be combined with an order.

[kevla]

Thanks for this I didnt see that option, I'll get a few now - brilliant! thought it was only large orders... glad that isn't the case...

I have ordered more parts as you say and my iPhone friends will be getting one of these, already had that idea

There is only one other part I'm struggling with and I am going to write a new post for that, wonder if you know anything about power inductors?

The one needed is :

RLB9012-100KJL: current 3.4Amp, tolerance 10%, dcr 45mOHM, Q 50 @2.52Mhz

however the ones I can get are :

RLB0914-100KL: current 2.7Amp, tolerance 10%, dcr 48mOHM, Q 50 @2.52Mhz

This has the greater than 1 amp needed, but I'm not sure about the +3mOHM?

do you think this will be OK?

thanks again!

[kevla]

$20 for 5 chips,
$30 for shipping,

I should get into the shipping business, Linear clearly make a killing out of it!!

[scottinnh]

$20 for 5 chips,
$30 for shipping,

I should get into the shipping business, Linear clearly make a killing out of it!!

Ouch. When I ordered in December 2010, I got 5 (parts+shipping) for a total of $30.

I'd go for the free samples. If it fails, email Adafruit customer service... if they have it in stock they MAY sell it to you, even though it's not a listed part.

Lastly I would consider the 8-SOIC package version from Digi-Key. Shipping first class US mail is like $3 (no tracking # etc but worth it).
If you need them, mini-pcbs that adapt 8-SOIC to 8-DIP are like 30 cents on ebay. I'd suggest this part if you're using the Adafruit PCB because there is a capacitor or resistor tucked in under the 1302 IC and socket.

Buy an extra chip if you go off the beaten path for your minty, just in case you break a pin or toast the chip. Hey it's Digi-key, they have something else you were planning to order someday. But know SOIC is pretty easy to solder (I've done it with the $22 iron sold here, and my eyes are not the best).

[scottinnh]

@kevla - I just saw this, and thought of your predicament.

http://www.evilmadscientist.com/article ... ketadapter

This is a good answer for a one-off application... order the SOIC LT1302 package from DigiKey, and adapt it.
This looks WAY easier than making a DIP8 adapter out of protoboard and male header pins. (Although it's still not as clean looking or quick as those Sparkfun/ebay SOIC-to-DIP PCB adapters).

[kevla]

Hey,

Thanks for this it's an interesting link...wonder if it would fit in the tin?
The two free samples arrived today.... Happy happy joy joy! Some dude is selling them in eBay for £10 and as I have 3 pcb's and 2 chips I'll get one from there.

Only bits still waiting for are the tins and pcb's... Oh yeah I can't find the 1% metal film resistors at 49.9k... Only 47k ones.
49.9k in the calculation will give 1.99759808 volts and two of them give the 500mah
The 47k ones will give 1.92622950 volts so not sure of that will be ok or not... But I'm going to find out

Thanks again!

[Shadowww]

aren't the resistors only needed to allow iPhone to charge?
I am not sure, but it seems like that. :S

[kevla]

aren't the resistors only needed to allow iPhone to charge?
I am not sure, but it seems like that. :S

They give it the 500mah at 2a so think its quite precise