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参数资料
| 型号： | MAX2244EBL-T |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | 衰减器 |
| 英文描述： | 2.5GHz, 22dBm/20dBm Power Amplifiers with Analog Closed-Loop Power Control |
| 中文描述： | 2400 MHz - 2500 MHz RF/MICROWAVE NARROW BAND LOW POWER AMPLIFIER |
| 封装： | 3 X 3 MM, UCSP-9 |
| 文件页数： | 9/14页 |
| 文件大小： | 312K |
| 代理商： | MAX2244EBL-T |
M
2.5GHz, 22dBm/20dBm Power Amplifiers with
Analog Closed-Loop Power Control
_______________________________________________________________________________________
9
RF Input/
SHDN
RFIN/
SHDN
is a dual-function input for a 2.4GHz to
2.5GHz RF signal and a DC-coupled shutdown function.
The input port is internally matched to 50
, making it
simple to interface the PAs to a 50
source without
external matching components. The PAs are designed to
amplify input signal levels of 0 to 4dBm and, although
the PAs function for input signals outside this range, out-
put power and efficiency degrade.
Note:
Ensure that the
RF signal is present at the input when the PA is enabled.
If the RF signal is not present at startup, the PA functions
like any closed-loop control system and automatically
goes into a high-gain state, amplifying and transmitting
noise. Avoid this mode of operation.
The second function of the RFIN/
SHDN
is shutdown con-
trol. A DC voltage at the input port digitally controls the
on/off state with standard CMOS levels. The PA is in low-
current shutdown when the DC voltage is a valid logic
low and is active for a valid logic high. Connect the
SHDN signal to the RFIN/
SHDN
through a 1k
resistor.
Connect the RF signal to the RFIN/
SHDN
with a 10pF
capacitor in series to block any DC from corrupting the
SHDN signal.
Output Matching
The output structure of these nonlinear PAs is an open-
collector transistor that requires external impedance
matching and pullup inductance for biasing. The recom-
mended output matching network is shown in the
Typical
Application Circuits
(Figure 1). The impedance presented
to the RFOUT pin is shown in Figure 2 and Table 2. This
impedance is specified relative to a reference plane at
the amplifier output into the matching network and load.
The matching network is for impedance transformation
that transforms 6
to 50
with the specified maximum
output power. The network also forms a lowpass filter that
provides attenuation for the 2nd and 3rd harmonics. A
shunt capacitor (C7) is needed to perform the transforma-
tion, and the inductive 50
transmission line (T2) is need-
ed to match that capacitance. A larger capacitor can be
used to increase the maximum output power, but the
transmission line also must be increased to maintain a
match with C7. A DC-blocking capacitor (C6) of 5pF to
10pF is necessary between the PA output and the trans-
mission line.
The pullup inductance from RFOUT to V
CC
serves three
main purposes: it resonates out the capacitive PA output,
provides biasing for the output stage, and becomes a
high-frequency choke to reduce RF energy from coupling
into V
CC
. The pullup inductance normally is a 50
trans-
mission line (T1); however, chip inductors can be used
instead. The typical application circuit terminates the
transmission line with a capacitor (C6).
Analog Power Control (PC)
The PAs use a closed-loop power-control system for
consistent output power across input power, supply volt-
age, and temperature. Output power is internally moni-
tored and compared to the desired setting on PC. The
control amplifier then adjusts the first-stage variable-gain
amplifier until the output power matches the desired set-
ting. The result is that the output power is controlled by
the voltage applied to PC.
The power-control voltage range at PC for the
MAX2244/MAX2246 is 0 to 2V. Output power remains at
its minimum for V
PC
between 0 and 0.4V. At approxi-
mately 0.4V, output power increases exponentially until
V
PC
= 2V, where output power is 22dBm (MAX2244) or
20dBm (MAX2246). See Figures 3a and 3c for the rela-
tionship between V
PC
and output power for the
MAX2244 and MAX2246, respectively.
Likewise, the MAX2245 output power is controlled by
V
PC
, but with a different power-control range. The power-
control voltage range of the MAX2245 is 0 to 2.2V, with
output power beginning to increase when V
PC
= 0.9V.
Figure 3b shows the V
PC
and output power relationship
for the MAX2245.
MATCHING IMPEDANCE FOR RFOUT
PIN
SMITH CHART
MAX2244: 6.26
+ j13.56
AT 2.45GHz
MAX2245: 6.35
+ j13.25
AT 2.45GHz
MAX2246: 5.50
+ j13.50
AT 2.45GHz
Figure 2. Impedance of Matching Network at RFOUT Pin
MAX2244
MAX2245
MAX2246
FREQUENCY
GHz
REAL
(
)
6.47
6.26
6.06
IMAG
(
)
13.2
13.5
13.9
REAL
(
)
6.61
6.35
6.11
IMAG
(
)
12.94
13.25
13.59
REAL
(
)
5.73
5.50
5.27
IMAG
(
)
13.01
13.50
14.02
2.40
2.45
2.50
Table 2. Matching Network Impedance
相关PDF资料 |
PDF描述 |
|---|---|
| MAX2246 | 2.5GHz, 22dBm/20dBm Power Amplifiers with Analog Closed-Loop Power Control |
| MAX2246EBL-T | 2.5GHz, 22dBm/20dBm Power Amplifiers with Analog Closed-Loop Power Control |
| MAX2245EBL-T | 2.5GHz, 22dBm/20dBm Power Amplifiers with Analog Closed-Loop Power Control |
| MAX2244 | 2.5GHz, 22dBm/20dBm Power Amplifiers with Analog Closed-Loop Power Control |
| MAX2244-MAX2246 | 2.5GHz, 22dBm/20dBm Power Amplifiers with Analog Closed-Loop Power Control |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX2244EBL-T10 | 功能描述:射频放大器 RoHS:否 制造商:Skyworks Solutions, Inc. 类型:Low Noise Amplifier 工作频率:2.3 GHz to 2.8 GHz P1dB:18.5 dBm 输出截获点:37.5 dBm 功率增益类型:32 dB 噪声系数:0.85 dB 工作电源电压:5 V 电源电流:125 mA 测试频率:2.6 GHz 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:QFN-16 封装:Reel |
| MAX2244EVKIT | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Evaluation Kit for the MAX2244/MAX2245/MAX2246 |
| MAX2244-MAX2246 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:2.5GHz, 22dBm/20dBm Power Amplifiers with Analog Closed-Loop Power Control |
| MAX2245 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:2.5GHz.22dBm/20dBm Power Amplifiers with Analog Closed-Loop Power Control |
| MAX2245EBL | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
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