Fibocom G610 Hardware User Manual page 14

surges from the power supply, which causes temporary voltage drops of the power supply level. The
transmission bursts consume the most instantaneous current, and therefore cause the largest
voltage drop. If the voltage drops are not minimized, the frequent voltage fluctuations may degrade
the G610 performance.
BATT
TX_EN
It is recommended that the voltage drops during a transmit burst will not exceed 300mV,
measured on the G610 interface connector. In any case, the G610 supply input must not drop below
the minimum operating level during a transmit burst. Dropping below the minimum operating level
may result in a low voltage detection, which will initiate an automatic power-off.
To minimize the losses and transients on the power supply lines, it is recommended to follow
these guidelines:
 Use a 1000 uF, or greater, low ESR capacitor on the G610 supply inputs. The capacitor
should be located as near to the G610 interface connector as possible.
 Use low impedance power source, cabling and board routing.
 Use cabling and routing as short as possible.
 Filter the G610 supply lines using filtering capacitors, as described in the table.
Recommended
Capacitor
1000 uF
10 nF, 100 nF
G610 GPRS Module Hardware User Manual
Usage
GSM Transmit current serge
Digital switching noise
Description
Minimizes power
during transmit bursts. Use maximum
possible value.
Filters digital logic noises from clocks
and data sources.
300mV max
3.3V min
supply losses
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