Technical information

Power Supply
10 G24-L Module Hardware Description November 15, 2008
Power Supply
The G24-L power supply must be a single external DC voltage source of 3.3V to 4.2V. The power
supply must be able to sustain the voltage level during a GSM transmit burst current surge, which
may reach 2.0A.
The G24-L interface connector has 8 contacts for the main power supply, as described in
Table 2-2. All these contacts must be used for proper operation.
Power Supply Design
Special care must be taken when designing the power supply of the G24-L. The single external
DC power source indirectly supplies all the digital and analog interfaces, but also directly
supplies the RF power amplifier (PA). Therefore, any degradation in the power supply
performance, due to losses, noises or transients, will directly affect the G24-L performance.
The burst-mode operation of the GSM transmission and reception, draws instantaneous current
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 G24-L performance.
Figure 2-2 illustrates the power supply behavior during GSM transmission.
Figure 2-2: Transmission Power Drops
Table 2-2:
Power Supply Signals
Pin # Signal Name Description
1-4 GND Main ground connection for
G24-L module.
5-8 VCC
DC supply input for G24-L mod-
ule.
V
IN
= 3.3 V to 4.2 V
I
RMS
= 550 mA during multislot
transmission
I
MAX
= 2 A during transmit bursts