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I've been trying to find a low-power flash storage solution. It needs to have built-in management (finding bad blocks, wear leveling, etc), so I've been looking at eMMC chips. But the specs on almost all chips in this family seem to be hidden behind some kind of barrier. With the good manufacturers, all you have to do is sign up for an account to view the datasheets. Some manufacturers (like Samsung) make it seemingly impossible to view any information on the chips, other than throughput.

How do designers normally find information about these sorts of chips? Is there any hope for someone looking to only produce a few thousand units or less? Should I call it quits and just use a microSD / microSD slot assembly?

EDIT While I am asking this for general advice about sourcing managed flash, I want to mention that my specific application currently only uses about 120mW. Additionally, only reading will be performed on the flash.

TreyK
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  • Semiconductor manufacturers are always looking for a design win where their products will be incorporated into zillions of production units, so your best chance at getting down to the technical nitty-gritty is to contact them personally and start a dialogue. – EM Fields Aug 26 '16 at 16:49

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As someone who has made FLASH, I would say that you should just use a MicroSD card. Firstly, it's really easy to get. Secondly, you cannot probably afford the cost of dealing with suppliers for what you'll get out of it.

Most FLASH storage is relatively low power to read, but writing takes a lot more power. My FLASH took 1nA per bit for 1uS to program at 5V. The erasing took a lot more power because we used tunneling and had to "ramp up" the circuits. Basically, we erased blocks and then programmed bits.

I suspect that the power cost of FLASH is just a drop in the bucket of total power consumption.

Community
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b degnan
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  • "you cannot probably afford the cost of dealing with suppliers for what you'll get out of it" - mind elaborating on this? – TreyK Aug 26 '16 at 17:31
  • The problem is the "few thousand" of units. Most manufactures don't leave parts just sitting around, so you make things on demand. You might be able to get a minimum order of 1k in there, but usually they are in the 10k range, so that's just 10x more than you need. If I would make the part for you, it'd be in millions. MicroSD cards are available, cheap and relatively low power. If you want to save power on the board, just burn it on the SDcard and then just figure out some way to save power with few IO writes or a slightly more efficient power regulator. – b degnan Aug 26 '16 at 17:38
  • @bdegnan: Well, even if they don't start a run for an order of 1000, they may certainly be willing to fulfill it the next time a high volume customer orders a million of the same part number. – Ben Voigt Sep 25 '16 at 19:08