Motorola W24 Manual De Usuario
Power Supply
10
Module Hardware Description
May 31, 2008
Power Supply
The W24 power supply must be a single external DC voltage source of 3.3V to 4.2V. In order to
support the stacked configuration, i.e. when G24 cellular module is coupled on the W24 module,
the power supply must be able to sustain the required voltage level during a GSM transmit burst
current surge, which may reach 2.0A.
support the stacked configuration, i.e. when G24 cellular module is coupled on the W24 module,
the power supply must be able to sustain the required voltage level during a GSM transmit burst
current surge, which may reach 2.0A.
The W24 interface connector has 8 contacts for the main power supply, as described in
All these contacts must be used for proper operation.
Power Supply Design
Note:
The power design considerations show maximum requirements for stacked
configuration.
configuration.
Special care must be taken when designing the power supply of the W24 in stacked configuration.
The single external DC power source indirectly supplies all the digital and analog interfaces, but
also directly supplies the G24 RF power amplifier (PA). Therefore, any degradation in the power
supply performance, due to losses, noises or transients, will directly affect the G24 performance.
The single external DC power source indirectly supplies all the digital and analog interfaces, but
also directly supplies the G24 RF power amplifier (PA). Therefore, any degradation in the power
supply performance, due to losses, noises or transients, will directly affect the G24 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.
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 W24 and G24 performance.
voltage drop. If the voltage drops are not minimized, the frequent voltage fluctuations may
degrade the W24 and G24 performance.
Table 2-2: Power Supply Signals
Pin #
Signal Name
Description
1-4
GND
Main ground connection for W24
module.
module.
5-8
VCC
DC supply input for W24 module.
V
V
IN
= 3.3 V to 4.2 V
I
RMS
= 250 mA during transmis-
sion (Stand alone)
I
I
RMS
= 900 mA during multi-slot
transmission (with G24)
I
I
MAX
= 2.5 A during transmit
bursts