acpm-7813 Avago Technologies, acpm-7813 Datasheet - Page 12

• Manufacturer Part Number: acpm-7813
• Description: Cdma/amps Power Amplifier Module
• Manufacturer: Avago Technologies

2. Step Bias Control and Dynamic Bias Control
(if controled PDM1)
The PDM1 output from the baseband IC can be used
to create a software-programmable voltage, to be used
at the phone designer’s discretion. To get high
efficiency and better ACPR, the phone designers can
change control voltage of the PA by adjusting PDM1
voltage according to output power of PA. A caution
when using this approach—careful consideration must
be made to to avoid an abrupt discontinuity in the
output signal when the step bias control voltage is
applied.
The figure below is an example of how to control the
PA for multiple bias points using the PA_ON and Vcntl
pin.
If PDM1 can be controlled then same circuit can be used for Dynamic bias control.
12
Power Mode
Shut Down
Low Power
Mid Power
High Power
To Duplexer
Vdd1
Vcntl
Vdd2
Vbias
PA
PA_ON
LOW
HIGH
HIGH
HIGH
Switch Circuit for PA
Battery
Enable
Vcntl
0V
1.2V
1.6V
2.5V
TxIC
C1
R1
Power Range
—
~ -5 dBm
-5 dBm ~ 13 dBm
13 dBm ~ 28.5 dBm
PA_ON
PDM1
Baseband
IC