ML2731
PRELIMINARY
FUNCTIONAL DESCRIPTION
VCC Supply
Voltage
PA Enable
signal (PAEN)
PA on/off switch and
current sense
Baseband IC
DAC
VPA
VCC
Drain
PA Bias controller
Increase gate
Reference current
for PA control
VBIAS
Measure error
(wanted current
Vs actual current)
PA
(GaAs FET)
voltage to
increase PA
current
REXT
OR
Gate
bias
VCC
R1
VREF
Source
Negative
voltage
generator
R2
GND
Figure 9: PA Current Control Loop Circuits
VPA Current vs. Vcontrol
600
500
400
300
200
100
12KΩ
24KΩ
0
0
0.5
1
1.5
2
2.5
3
V Control (V)
Figure 10: PA Current Control Loop Operation With REXT At
12kW and 24kW
January, 2000
9
PRELIMINARY DATASHEET
MICRO-LINEAR [ MICRO LINEAR CORPORATION ]
