Power Supply; Power Supply Design; Power Supply Signals; Recommended Power Supply Filtering - Motorola 8900 - Blackberry Curve Cell Phone OEM Car Charger Developer's Manual

Power Supply

Power Supply
The C24 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 transmit current surge, which may reach
600 mA.
The C24 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

Special care must be taken when designing the power supply of the C24. 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 C24 performance.
It is recommended that any voltage drops during transmission will not exceed 300mV, measured
on the C24 interface connector. In any case, the C24 supply input must not drop below the
minimum operating level during transmission. Dropping below the minimum operating voltage
may degrade the module performance.
To minimize the losses and transients on the power supply lines, it is recommended to follow
these guidelines:
Use a 100 uF, or greater, low ESR capacitor on the C24 supply inputs. The capacitor should
•
be located as near to the C24 interface connector as possible.
Use low impedance power source, cabling and board routing.
•
Use cabling and routing as short as possible.
•
Filter the C24 supply lines using filtering capacitors, as described in
•
10
Table 2-2: Power Supply Signals
Pin # Signal Name
GND
1-4
VCC
5-8
Table 2-3: Recommended Power Supply Filtering
Capacitor Usage
100 uF Transmit current serge
10 nF, 100 nF Digital switching noise Filters digital logic noises
C24 Module Hardware Description
Description
Main ground connection for C24
module.
DC supply input for C24 module.
V = 3.3 V to 4.2 V
IN
I = 600 mA during transmis-
RMS
sion
Table
Description
Minimizes power supply
losses during transmission.
from clocks and data sources.
December 15, 2008
Table 2-2.
2-3.