X9470 Datasheet, PDF (18/25 Pages) Xicor Inc. – RF Power Amplifier (PA) Bias Controller

Preliminary Information
Figure 6. Dynamic Biasing Technique: Automatic DC Bias Operating Point Adjustment
State 0
Monitor
Mode
RF signal
State 1
Calibration
(no RF present)
State 2
RF present
V_REF
Set Operating Range Scale for Bias Adjustment
State 3
Recalibrate bias
point for drift
and temperature
X9470
State 4
shut
down
CS
SCL
INC/DEC
Bias Adjustment ON
Bias Adjustment OFF
Saves wiper position to
volatile memory
BiasLock
Bias Adjustment ON
BiasLock
SHDN
V_BIAS
R_bias default is
zero point of R_total
1
2
Latch R_bias DC point
in calibration vs V_REF
3
RF present
Turn off
Bias
Adjustment
6
Shut
down
4
R_bias increase/decrease
after RF present due to
temperature increase &
V_GS-threshold drift
5
IDQ vs. gate
voltage bias
optimized
Automatic Bias Adjustment
REV 11.16 3/20/03
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