Suspended mode

Andy Green andy at
Thu Feb 7 17:33:38 CET 2008

Hash: SHA1

Somebody in the thread at some point said:
> Hi Andy:
>> Also check all the supply rails like V-DBB, V-IO, V-FLASH (hmm),
>> V_SRAM, V-SIM, V_RTC (hmm) and V-ABB to find ones that have >=1.8V
>> in suspend, then try to remove any pullup to these rails, eg, if
>> V-SIM has >= 1.8V, try to remove R1010 as a test.
> I power off GSM modem and set RX, TX, CTS, and RTS to output Low. The
> VBAT is 0.004. V-DBB, V-IO, V-FLASH,V-SRAM,V-SIM,V-RTC,and V-ABB are
> almost zero. I found total current is 4~5mA. It is better than before
> (8~9mA).

Hi Allen -

In my travels trying to understand another problem I came across R1519
on the CPU schematic -- it pulls TX_MODEM up by 10K to 3.3V.

Do we really need this?  We can save <=330uA if the GSM stuff is powered
down by removing it.  Hey it sounds like nothing but it is up to 6% of
that 5mA suspend current.

Plus it can be source of the 2V on GSM Vdd you were trying to track down?

- -Andy
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