rf3230 RF Micro Devices, rf3230 Datasheet - Page 13

• Manufacturer Part Number: rf3230
• Description: Quad-band Gmsk Txm, 2 Umts Switch Ports
• Manufacturer: RF Micro Devices

Figure 1: Basic PowerStar® Circuit Diagram
The PowerStar® power control relationship is described in Equation 1 where V
the other variables are constants for a given amplifier design and load. The equation shows that load impedance affects out-
put power, but to a lesser degree than V
power variation is eliminated. Another important result is that the equation provides a very linear relationship between V
and P
Equation 1: Output Power versus Voltage Relationship
The RF signal applied at RFIN of the amplifier must be a constant amplitude signal and should be high enough to saturate the
amplifier. The input power (P
maximum output power and the potential for more variation of output power over extreme conditions. Higher input power is
unnecessary and will require more current in the circuitry driving the power amplifier. A higher input power may also couple to
the output and will increase the minimum output power level.
DS100406
OUT
expressed as V
V
RAMP
TX ENABLE
RMS
.
IN
RF IN
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at ([phone] or [e-mail].
) range is indicated in the specifications. Power levels below this range will result in reduced
P
dBm
CC
supply variations. Since the architecture regulates V
=
10
⋅
log
(
------------------------------------------ -
8 R
2 V
+
-
⋅
⋅
LOAD
CC
H(s)
–
V
⋅
CC
SAT
10
is the voltage from the linear regulator and
3 –
)
V
2
BATT
V
CC
CC
RF OUT
, the dominant cause of
RF3230
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RAMP