Reliability of microcontroller silicon die glue on top of another die

May 31, 2017 43 Replies

Google is your friend

Page 11:

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In this case it's cheaper, as far as I know because they only pay ARM licencing for a chip without flash, and they have good grip on the flash technology

It's not specifically stated. For reference look up the STM32 datasheet

Cheers

Klaus

Check the reverse engineering document. They have serial flash, so it is up to 3MB

Cheers

Klaus

Yes, exactly. And when before in history did you have the opportunity to have a almost real second source for a microcontroller, like here for the STM32/GD32

You have to go back to the 8051 I guess

Cheers

Klaus

When I quote microcontrollers, there a strong correlation between flash and price, so that is not true. In some cases it's actually the testing of the flash that makes the difference, and the yields

Separate processor and memory dies inside one device is not new - though usually it is a little neater than this example. While flash is cheap in itself, the die stackup (number and type of layers, sizes, etc.) that is ideal for flash is not the same as the stackup that is ideal for a microcontroller or SRAM. With modern flash designs, and modern microcontroller designs, it is not too much of a compromise to combine them - and it results in a much cheaper chip. But for older designs, there was a bigger difference - it would not surprise me if a two-die solution had lower power, for example.

If I have to use Google to find a data sheet, I figure the company must not make the parts anymore or at least aren't looking for sales.

Ok, a BS marketing price. Which part, what quantity...

Who says it is cheaper? If you can't buy them it doesn't matter. I can't find anyone who sells them.

The point is 300 uA/MHz is not even in the running for low power these days. The fact that running from SRAM *should* use less current doesn't mean their chips are competitive. I believe the forefront of low power ARMs is in the 100 uA/MHz these days. Am I mistaken?

Rick C

You've said so many things contrary to the datasheet and yourself, and it's equally opaque, that I have no idea what you're talking about anymore.

Well, perhaps as klugy as adding another level of cache to an M3.

Duh! WTF are we talking about one-off ARMs?

SRAM takes 10x the silicon. End of discussion.

IT'S NOT ON-CHIP MORON!

Bullshit.

I can imagine.

I talked to the sales guy at electronica 2016 and he stated even lower prices in volume. So the price is ok

They are just moving to the european marked, have sold 100 million devices in china, so I think you will be hearing about them a lot in the future

Sort of. THe low current is normally the M0+. The older devices, value line, is about 1mA/MHz

Cheers

Klaus

Bottom line: It's a frappin' kludge.

Name them, I do not think I have stated anything misleading?

Check for example the STM32F130 datasheet, page 42:

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SRAM is about 10% lower power consumption than flash

Cheers

Klaus

You are comparing the Giga part to an ST part that is 10 years old, right?

300 uA/MHz is not on the forefront of power efficiency. TI and Silicon Labs have CM3 and CM4 parts that can reach power consumption below 100 uA/MHz.

The issue is not about features but about specifications. I don't care how an MCU gets low power. The Giga part is not in the realm of what is considered low power anymore.

Rick C

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Yes, but you certainly won't get a low power ST part in that price range

Low power is a sales feature until they all have that feature ?

Comparing apples to apples ?

Cheers

Klaus

The point is you are claiming the use of an external Flash allows *lower* power operation. That is irrelevant when the chip spec is *much* worse than others in the same performance class. If you want to compare prices, then compare prices. This isn't about apples.

The $0.30 price is not a quote, it is a mythical price based on buying some enormous quantity. Since their parts aren't actually offered for sale anywhere that I would be buying them it doesn't matter what price a marketing sheet says they go for. I did find Symmetry that offers them for $0.71.

Rick C

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Some parts are not offered in public, they are offered with distributors fr ame work agreements

Cheers

Klaus

In other words, if you aren't buying a million a year, buzz off! Got it!

Rick C

Is the flash on-chip or not? Is the power lower operating from flash, or not? (Hint: if it's a flash part, it's not operating, with zero wait-state, from flash).

Are you really the distributor for this junk?

That was shown in the original post, this link:

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2 dies. AFAICT the flash is loaded to SRAM during startup (50ms startup), and then excutions runs in SRAM, hence the 0 wait state

Lower from SRAM, datasheet does not state the figure explicitly

Yes, sure, been lurking in this NG for 20 years, for the hope that you would come by and pressure me for free samples.

Cheers

Klaus

The datasheet (and you) claimed that it was a single chip. You also claimed that it was faster when operating out of SRAM than flash. Obviously false, since it can't operate out of flash.

But it *can't*.

I don't waste time on junk but you're welcome to drool over it some more.

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