[gta02-core] Modem schematic / RF help needed

[Dave Ball]

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:
http://n2.nabble.com/Modem-schematic-RF-help-needed-tp3591236p3624034.html
http://n2.nabble.com/Modem-schematic-RF-help-needed-tp3591236p3628602.html

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,

Dave