Data Sheet
FEATURES
Output frequency range: 700 MHz to 2700 MHz
Modulation bandwidth: dc to 160 MHz (large signal BW)
1 dB output compression: 5.6 dBm @ 2140 MHz
Output disable function: output below –50 dBm in < 50 ns
Noise floor: –156 dBm/Hz
Phase quadrature error: 0.3 degrees @ 2140 MHz
Amplitude balance: 0.1 dB
Single supply: 4.75 V to 5.5 V
Pin compatible with AD8345/AD8346s
16-lead, exposed-paddle TSSOP package
700 MHz to 2700 MHz
Quadrature Modulator
FUNCTIONAL BLOCK DIAGRAM
AD8349
IBBP 1
16 QBBP
IBBN 2
15 QBBN
COM1 3
Σ
14 COM3
COM1 4
13 COM3
LOIN 5
PHASE
SPLITTER
12 VPS2
LOIP 6
11 VOUT
APPLICATIONS
Cellular/PCS communication systems infrastructure
WCDMA/CDMA2000/PCS/GSM/EDGE
Wireless LAN/wireless local loop
LMDS/broadband wireless access systems
VPS1 7
BIAS
ENOP 8
10 COM3
03570-0-001
9 COM2
Figure 1.
PRODUCT DESCRIPTION
The AD8349 is a silicon, monolithic, RF quadrature modulator
that is designed for use from 700 MHz to 2700 MHz. Its
excellent phase accuracy and amplitude balance enable high
performance direct RF modulation for communication systems.
The differential LO input signal is buffered, and then split into
an in-phase (I) signal and a quadrature-phase (Q) signal using a
polyphase phase splitter. These two LO signals are further
buffered and then mixed with the corresponding I channel and
Q channel baseband signals in two Gilbert cell mixers. The
mixers’ outputs are then summed together in the output
amplifier. The output amplifier is designed to drive 50 Ω loads.
The RF output can be switched on and off within 50 ns by
applying a control pulse to the ENOP pin.
The AD8349 can be used as a direct-to-RF modulator in digital
communication systems such as GSM, CDMA, and WCDMA
base stations, and QPSK or QAM broadband wireless access
transmitters. Its high dynamic range and high modulation
accuracy also make it a perfect IF modulator in local multipoint
distribution systems (LMDS) using complex modulation
formats.
The AD8349 is fabricated using Analog Devices’ advanced
complementary silicon bipolar process, and is available in a 16-
lead, exposed-paddle TSSOP package. Its performance is
specified over a –40°C to +85°C temperature range.
Rev. B
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
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