EEVblog #514 - $5 Mobile Phone Teardown - LG800G

[EEVblog]

What's inside a modern bare bones $5 mobile phone?
The LG800G available from Tracphone for $5:
http://www.tracfone-orders.com/bpdirect/tracfone/PhoneDetails.do?action=view&productVariantExtensionId=23192218

Datasheets:
http://www.infineon.com/dgdl/X-GOLD_213-pb.pdf?folderId=db3a304312fcb1bc0113000c158f0004&fileId=db3a30431ddc9372011e1fc7f7fd413d
http://www.rfmd.com/CS/Documents/7161DS.pdf
http://en.wikipedia.org/wiki/High-electron-mobility_transistor
http://www.broadcom.com/products/Bluetooth/Bluetooth-RF-Silicon-and-Software-Solutions/BCM2070

[marshallh]

IIRC the bga underfill is for shock protection (don't want the packages to shear off under excessive G's) and moisture/residue contamination. It will also inhibit tin whisker growth but I doubt that was a design concern.

[Lukas]

The golden can at 6:35 is much more likely to be a (MEMS) microphone than a filter.

[ivan747]

Very interesting video. The phone was more bare-bones than I thought it would be. It seems like with these SOCs evryone could design a cellphone (if you manage to get sent samples!).

I'm curious about the antenna. It resembles nothing you can see on textbooks. It seems to me that both antennas seem lossy and very far of ideal. The GSM antenna is divided in sections, which reminds me of yagi antennas, is that it? The bluetooth one seemed undersized, I don't even think that was quarter wavelength. I also guess using a chip antenna (they are fractal antennas the size of an SMT resistor) was more expensive than making the plastic spacers hold some cheap metal film.

[Stonent]

The antenna design resembles what they did on the old 7200 series blackberries. (When they were blue)

[Stonent]

Any chance of seeing if you can somehow drive the phone's LCD? I guess we'd need a data sheet though.

[Corporate666]

One want to take a wild ass guess at manufacturing cost for that phone?

I have no experience in large volumes like they would be doing, but I would have to guess easily $20 or so. 

[Electr0nicus]

Any chance of seeing if you can somehow drive the phone's LCD? I guess we'd need a data sheet though.

When you look at the connector at 7:40 in the video it's obvious that this display is driven using a parallel RGB Bus. The left 6 traces are likely the control signals. At least most displays use a minimum of 4 Signals (HSYNC, VSYNC, PCLK, DE). Depending on the manufacture there could be a few more signals, or there are some ground traces in between to improve signal quality. Then there are 16 thin traces in the middle of the connector. This is most likely the RGB data bus using a 5:6:5 arrangement (5Bits red, 6Bits green, 5Bits blue). The thicker traces on the right side of the connector are most likely traces for power and backlight.

[BravoV]

Dave, I think its safe to assume that now you know (for sure ?) at least one, who is contributed thumb downs at your videos. 

Don't know, but looks like it has nothing to do with the content anymore, and becoming its personal ? Related post -> HERE

[Stonent]

Any chance of seeing if you can somehow drive the phone's LCD? I guess we'd need a data sheet though.

When you look at the connector at 7:40 in the video it's obvious that this display is driven using a parallel RGB Bus. The left 6 traces are likely the control signals. At least most displays use a minimum of 4 Signals (HSYNC, VSYNC, PCLK, DE). Depending on the manufacture there could be a few more signals, or there are some ground traces in between to improve signal quality. Then there are 16 thin traces in the middle of the connector. This is most likely the RGB data bus using a 5:6:5 arrangement (5Bits red, 6Bits green, 5Bits blue). The thicker traces on the right side of the connector are most likely traces for power and backlight.

Oh yeah, obviously, of course. 

[oakkar7]

One want to take a wild ass guess at manufacturing cost for that phone?

I have no experience in large volumes like they would be doing, but I would have to guess easily $20 or so.

I agree with Corporate666 guess, $20.

Here is Bunnie houng blog post china cheapo phone. It's not a advanced touch semi smart phone but very basic bare phone. The difference between these two phones is that china's The $12 Gongkai phone is real manufacturing cost.
http://www.bunniestudios.com/blog/?p=3040

[EEVblog]

Don't know, but looks like it has nothing to do with the content anymore, and becoming its personal ?8;image[/img]

It's always personal with people who leave emotive comments. Which is fine of course, I like passion. But when people just keep complaining about the same thing thing over and over again, it gets very boring very quickly, for everyone. If he does it again I'll simply block him. Which will of course lead to inevitable accusations of not being able to handle any negative feedback 

[EEVblog]

One want to take a wild ass guess at manufacturing cost for that phone?
I have no experience in large volumes like they would be doing, but I would have to guess easily $20 or so.

Someone mentioned the LCD is an LG, and that's something to remember, LG are pretty big and make a lot of stuff, so the cost might be less than you might think.
I reckon about $15-$20, but entirely depends on how you factor in the internal pricing in their own factories.

[BravoV]

If he does it again I'll simply block him. Which will of course lead to inevitable accusations of not being able to handle any negative feedback 

Well, in this particular issue, I'm suggesting just leave the judgment to "majority", and ignore those really low dB "noise". 

C'mon, you now this better, its not worth the effort ironing out a trivial few uV ripple at a 100 volt power supply rail. 

[EEVblog]

Well, in this particular issue, I'm suggesting just leave the judgment to "majority", and ignore those really low dB "noise". 

I can do that, but I can't expect others to do the same. That means trolls like Anton lead to nasty debates in every video if allowed to continue.

[moemoe]

When talking about "full size sim card", I think of the leftmost in this picture. You probably ment a mini-sim, contrary to micro- and nano-SIM.

Image Source: http://en.wikipedia.org/wiki/File:GSM_SIM_card_evolution.svg CC-BY-SA

[tinhead]

Someone mentioned the LCD is an LG

that display (LM283DN1A) is know, see service manual from other phone

http://diagramas.diagramasde.com/celulares/EN_LG-T325_SVC_ENG_101012%5Bup.by.nasirahmed%5D.pdf

so it should be made by TOVIS. Interessting is that detail : RENESAS(R61520), that's the display controller.
There is as well pinout of that display, so this could help a lot already.

[LEECH666]

That little logo in the middle of the LION battery looks a little bit (politically) inappropriate (at least for the German viewers) to me.

[RupertGo]

Antennas in these things are pretty amazing things in their own right. when you think of the enormously variable RF environment they find themselves in and the large number of bands they have to  cover. It's a long way from swaring up a K40 for hi band. (If you know what that means, you shouldn't.)

I don't know if this is how LG does its antenna design (the Bluetooth one looks like a reasonably normal stub-matched radiator), but a lot of funky wprk has been done with evolutionary algorithms. Basically, you give the computer a set of mechanical and electromagnetic parameters and tell it to evolve the best design. It starts off with a very basic antenna, makes a series of random modifications, models them, picks the best result out of those, and repeats. NASA has done this with stipulations that the antenna must also be a structural part of another system, for example, stuff that classical antenna design techniques really can't tackle.

The results can look really weird, but work really well.

http://en.wikipedia.org/wiki/Evolved_antenna is, as usual, a decent jumping-off point.

[tinhead]

That little logo in the middle of the LION battery looks a little bit (politically) inappropriate (at least for the German viewers) to me.

no, there is no problem at all, oh well, maybe only for those who are a little bit dumb. Not only because swastika is something complettly differnt that you think

http://de.wikipedia.org/wiki/Swastika

but as well from (nazi) historical point of view there is nothing wrong with it - it is our history! Human being are like that, don't think too much, or you will find out that since 10000yrs the list of unnecessary wars was looong. My top 5 is:

- the loss of knownledge due wars/fire/etc., e.g. http://de.wikipedia.org/wiki/B%C3%BCcherverluste_in_der_Sp%C3%A4tantike
- 9/11 plains and (NIST) steel theoryand resulting irak war
- all crusades
- vietnam war
- WWII

But yeah, probably a dumb customs officer could confiscate that battrey 

[xrunner]

That cheap thing had an external ant connector - I've never had a cell phone that had an ext. ant. connection. 

[nathanpc]

That cheap thing had an external ant connector - I've never had a cell phone that had an ext. ant. connection. 

Most mobile phones have the external antenna jack, but it's usually hidden with a rubber cover.

[gardner]

external antenna jack

I have seen similar looking jacks on other phones, buried inside the battery compartment or behind a rubber seal.

I do not recognise the connector.  Is it a standard or something specific manufacturer by manufacturer?  Can you buy mating connectors from mouser or somewhere?  What is the standard?

Besides connection for car/base-station external aerial, another use might be for testing, to allow verification of the RF section during manufacturing -- especially full power output and high sensitivity.  Doing those tests through pads might be too noisy.

[Corporate666]

Antennas in these things are pretty amazing things in their own right. when you think of the enormously variable RF environment they find themselves in and the large number of bands they have to  cover. It's a long way from swaring up a K40 for hi band. (If you know what that means, you shouldn't.)

I don't know if this is how LG does its antenna design (the Bluetooth one looks like a reasonably normal stub-matched radiator), but a lot of funky wprk has been done with evolutionary algorithms. Basically, you give the computer a set of mechanical and electromagnetic parameters and tell it to evolve the best design. It starts off with a very basic antenna, makes a series of random modifications, models them, picks the best result out of those, and repeats. NASA has done this with stipulations that the antenna must also be a structural part of another system, for example, stuff that classical antenna design techniques really can't tackle.

The results can look really weird, but work really well.

http://en.wikipedia.org/wiki/Evolved_antenna is, as usual, a decent jumping-off point.

This is one of the great tid-bits of "I didn't know that!" type information that make this site great!

[Grapsus]

Very interesting tear down. Though I wouldn't say it is a "cheap ass" phone like the gonkai phone that someone pointed at previously. It's more an entry level phone for kids or people who don't care about apps. It even has a dedicated bluetooth chip !

The small chip near the Intel flash surrounded by caps is probably a power manager, responsible for regulating different voltages and charging the lithium battery.

The GSM antenna is pretty weird, I agree that it must come from some sort of optimization software to have the most isotropic radiation pattern possible. As for the fact that it's smaller than 1/4 wavelength, think of it as a patch antenna, because it's pretty far from being linear.