[gta02-core] Modem schematic / RF help needed

Dave Ball openmoko at underhand.org
Wed Sep 16 02:01:13 CEST 2009

Álvaro Lopes wrote:
> Werner Almesberger wrote:
>> Dave Ball wrote:
>>> I've just implemented this with the NTDG1100L (new part, so the symbol 
>>> could do with a review too),
>> - Why not reuse the SI1040X ? They're virtually identical.
> I asked myself the same question.
> But I guess Dave has a good answer for it. Actually I assumed you had discussed that on IRC. It's a new part, and might be hard to source (ie, not in stock for the first prototypes).

Unfortunately, I don't have a good answer :-)  I was away for a few 
days, but thought Werner / Rask had identified the NTDG1100L as the 
prefered solution:

I wasn't aware of the SI1040X, so I'm happy to look into using that 
instead - makes sense to avoid new components if we can.

> And I'd really prefer enabling that using a longer delay line (ie, CPU output). That would have other benefits too, like lower consumption at power up.

I'll admit to not knowing the PMU details, but can't we just delay the 
2v8 output until we need to power on the modem?  I couldn't see an 
advantage of having one powered up earlier than the other?

All the best,


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