Re: Garmin eMap: Dead?

Did I say for sure I know this is the cause? No, I didn't. However,
these problems do happen. Note that the emap is orphaned and it didn't
last all that long. Maybe there is a reason.

The other problem with your argument is to assume all emaps are the
same inside. These manufacturers often do cost cutting as the product
matures. What might be three chips becomes on chip in a later model.
Even the chips get altered over time. Some changes are to fix bugs,
other changes are just due to new tooling requirements due to tweaks in
the fab.

You really can't appreciate how difficult a task it is to do a good
undervoltage lockout. If you did, you wouldn't tempt fate. I've
designed chips that would have multiple levels of lockout to make it
bulletproof, but all this costs money that doesn't add function to the
end product.

Since the other poster thinks I pull stuff out of my ass, you can see
the term undervoltage lockout is real. Here it is on a Moto chip:
http://www.onsemi.com/site/products/summary/0,4450,NCP1571,00.html

Here is a good primer on DC/DC
http://www.altera.com/support/devices/power/regulators/pow-regulators.html
Imagine such a product with reasonably strong fets inside and the
undervoltage lockout isn't working. You can get a situation where a
circuit that should be pulsed is now on constantly, and you can bet
that will fry something even if the batteries are weak.

Trust me, there are design flaws out there. Nothing is really
foolproof.

.

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