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參數(shù)資料
| 型號： | MAX2720 |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | 1.7GHz to 2.5GHz, Direct I/Q Modulator with VGA and PA Driver |
| 中文描述： | 直接變換QPSK調制器，帶有VGA及PA驅動器，用于1.7GHz至2.5GHz應用 |
| 文件頁數(shù)： | 18/24頁 |
| 文件大?。?/td> | 319K |
| 代理商： | MAX2720 |
M
1.7GHz to 2.5GHz, Direct I/Q Modulator with
VGA and PA Driver
18
______________________________________________________________________________________
I/Q Modulator
The MAX2720/MAX2721 modulator is composed of a pair
of matched double-balanced mixers, an active LO quad-
rature generator, and a summing amplifier. The pair of
mixers accept differential I/Q baseband signals that
directly modulate the internal 0° and 90° LO signals
applied to the I/Q mixers. An external LO source drives
an internal LO quadrature generator that shifts the phase
of the LO signal applied to the Q mixer by 90° relative to
the LO signal applied to the I channel mixer. The modu-
lated output of the I/Q mixers is summed together, and
the undesired sideband is suppressed.
The I+, I-, Q+, and Q- input ports feature high-linearity
buffer amplifiers with a -1dB bandwidth of 20MHz and
a -3dB bandwidth of 38MHz (1k
I/Q source imped-
ance), and accept differential input voltages up to
630mVp-p. Input bandwith can be extended to beyond
100MHz by lowering the I/Q source impedance. The
ports are internally biased and therefore require DC-
blocking capacitors. For single-ended operation,
bypass the I- and Q- ports with a capacitor to ground
equal in value to the DC-blocking capacitors used on
the I+ and Q+ ports. See the
Typical Application Circuit
for recommended component values.
Variable Gain Amplifier (VGA)
A VGA follows the summing amplifier of the I/Q modulator.
Apply a voltage between 0.5V and 2.5V to PC to vary
the output power of the modulator over a 32dB span.
The open-collector MODOUT output requires a pull-up
inductor to V
CC
for proper biasing, an external matching
network for optimum power transfer, and a DC-blocking
capacitor. Since the MAX2720/MAX2721 are optimized
for different frequency ranges, they require different
output matching networks. See the MAX2720 and
MAX2721
Typical Application Circuit
for recommended
component values. See Table 1 for matching to other
frequencies.
LO Buffer and LO Frequency Doubler
The MAX2720/MAX2721 feature an internal LO frequency
doubler that allows the external LO source to run at full or
half frequency (Table 2). Operating the LO at half fre-
quency reduces injection-pulling of the voltage-con-
trolled oscillator (VCO) from the PA, and reduces the
complexity of designing a high-frequency VCO. An
internal two-pole bandpass filter is integrated before
the LO phase-shift network to help reduce LO harmonic
content and spurious mixing.
To enable the LO frequency doubler, drive
ENX2
to a
logic-level low and operate the external LO source at
half the RF carrier frequency. To disable the LO
frequency doubler, drive
ENX2
to a logic-level high and
run the external LO source at the RF carrier frequency.
See Table 2 for LO input frequency ranges.
The LO port is a single-ended input that achieves a
VSWR of better than 2:1 over the specified LO input
frequency range. Since the port is internally terminated
with 50
, it requires a DC-blocking capacitor. See the
Typical Applications Circuits
for recommended compo-
nent values. For optimum performance, drive the LO
port with an input power of -16dBm to -10dBm. Driving
the LO port with lower input power levels may affect
quadrature performance, while higher input powers
may increase LO leakage.
PA Driver Amplifier
The PA driver provides a gain of 13.5dB for the
MAX2720 and 11.5dB for the MAX2721. The DRIN
input port requires an external matching network and a
-71.0
-73.0
-68.9
-93.8
-94.4
0.832
0.811
0.896
0.884
-91.3
-66.6
0.861
S22 PHASE
(degrees)
0.909
1750
1800
1850
1900
-77.1
-79.6
75.4
-97.1
-100.5
0.866
0.891
0.878
0.892
-94.8
-74.6
0.834
0.868
1950
2000
2050
2100
-94.7
0.807
0.871
-86.5
0.861
0.914
S22 PHASE
(degrees)
S22 MAG
S22 MAG
FREQUENCY
(MHz)
1700
2200
2250
2150
2100
FREQUENCY
(MHz)
2400
2450
2350
2300
Table 1. VGA MODOUT S22 Parameters (V
CC
= 3.0V, V
PC
= 2.5V, T
A
= +25°C)
82.5
-104.5
0.905
0.897
2500
MAX2720
MAX2721
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相關代理商/技術參數(shù) |
參數(shù)描述 |
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| MAX2720EUP | 功能描述:射頻接收器 RoHS:否 制造商:Skyworks Solutions, Inc. 類型:GPS Receiver 封裝 / 箱體:QFN-24 工作頻率:4.092 MHz 工作電源電壓:3.3 V 封裝:Reel |
| MAX2720EUP+ | 功能描述:射頻接收器 RoHS:否 制造商:Skyworks Solutions, Inc. 類型:GPS Receiver 封裝 / 箱體:QFN-24 工作頻率:4.092 MHz 工作電源電壓:3.3 V 封裝:Reel |
| MAX2720EUP+T | 功能描述:射頻接收器 RoHS:否 制造商:Skyworks Solutions, Inc. 類型:GPS Receiver 封裝 / 箱體:QFN-24 工作頻率:4.092 MHz 工作電源電壓:3.3 V 封裝:Reel |
| MAX2720EUP-T | 功能描述:射頻接收器 RoHS:否 制造商:Skyworks Solutions, Inc. 類型:GPS Receiver 封裝 / 箱體:QFN-24 工作頻率:4.092 MHz 工作電源電壓:3.3 V 封裝:Reel |
| MAX2720EVKIT | 功能描述:射頻接收器 RoHS:否 制造商:Skyworks Solutions, Inc. 類型:GPS Receiver 封裝 / 箱體:QFN-24 工作頻率:4.092 MHz 工作電源電壓:3.3 V 封裝:Reel |
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