Do you have "g18 Developer Manual Ver2.0.pdf"

"The g18 is specified to operate from 3.0V to 6.0V on the g18 input (after
the flat cable losses). In
order to be able to work in the lowest battery values it is important to
verify the losses in the
power supplies lines, Flat cable and in the user PCB.
The g18 is a GSM phone that transmits in pulses of about 0.5mS every 4.6mS.
The Peak current is about 1.5A.The VCC line will drop down in the TX
periods:Figure 6 - The VCC signal during TX periods
In order to minimise the ?it is recommended to use a short Flat cable as
possible and to put a 1000uF capacitor (or maximum possible) in the g18 VCC
input.Note: In addition to the losses recommendation, it is recommended to
have a current limit in the power supply ( 2.5-3A) in order to avoid damages
in case of short."

----- Original Message -----
From: <egnascimento@YAHOO.COM.BR>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Friday, September 26, 2003 10:02 PM
Subject: [EE] GSM module and HandsFree Kit


> Hi all,
>     Please, I need a help working with GSM modules...
>     I have implemented a solution with GSM g18 and automotive hands free.
>     My real problem is when the power supply acquire a ripple deriving
from
> current peaks of gsm module.
>     These peaks influence in audio out.
>     I know that analogic ground and digital ground can't be connected.
>     But how can I work without this reference? Is there a way to remove
> consumption peaks from power supply?
>
> Please help me!
> Thanks in advance!
>
>
>
>
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