AD8346 Datasheet, PDF (1/12 Pages) Analog Devices – 0.8 GHz-2.5 GHz Quadrature Modulator

a
FEATURES
High Accuracy
1 Degree rms Quadrature Error @ 1.9 GHz
0.2 dB I/Q Amplitude Balance @ 1.9 GHz
Broad Frequency Range: 0.8 GHz–2.5 GHz
Sideband Suppression: –46 dBc @ 0.8 GHz
Sideband Suppression: –36 dBc @ 1.9 GHz
Modulation Bandwidth: DC–70 MHz
0 dBm Output Compression Level @ 0.8 GHz
Noise Floor: –147 dBm/Hz
Single 2.7 V–5.5 V Supply
Quiescent Operating Current: 45 mA
Standby Current: 1 ␮A
16-Lead TSSOP Package
APPLICATIONS
Digital and Spread Spectrum Communication Systems
Cellular/PCS/ISM Transceivers
Wireless LAN/Wireless Local Loop
QPSK/GMSK/QAM Modulators
Single-Sideband (SSB) Modulators
Frequency Synthesizers
Image Reject Mixer
0.8 GHz–2.5 GHz
Quadrature Modulator
AD8346
FUNCTIONAL BLOCK DIAGRAM
IBBP 1
IBBN 2
COM1 3
COM1 4
LOIN 5
LOIP 6
VPS1 7
ENBL 8
PHASE
SPLITTER
BIAS
AD8346
16 QBBP
15 QBBN
14 COM4
13 COM4
12 VPS2
11 VOUT
10 COM3
9 COM2
PRODUCT DESCRIPTION
The AD8346 is a silicon RFIC I/Q modulator for use from
0.8 GHz to 2.5 GHz. Its excellent phase accuracy and ampli-
tude balance allow high performance direct modulation to RF.
The differential LO input is applied to a polyphase network
phase splitter that provides accurate phase quadrature from
0.8 GHz to 2.5 GHz. Buffer amplifiers are inserted between
two sections of the phase splitter to improve the signal-to-noise
ratio. The I and Q outputs of the phase splitter drive the LO
inputs of two Gilbert-cell mixers. Two differential V-to-I con-
verters connected to the baseband inputs provide the baseband
modulation signals for the mixers. The outputs of the two mixers
are summed together at an amplifier which is designed to drive a
50 Ω load.
This quadrature modulator can be used as the transmit modula-
tor in digital systems such as PCS, DCS, GSM, CDMA, and
ISM transceivers. The baseband quadrature inputs are directly
modulated by the LO signal to produce various QPSK and
QAM formats at the RF output.
Additionally, this quadrature modulator can be used with direct
digital synthesizers in hybrid phase-locked loops to generate
signals over a wide frequency range with millihertz resolution.
The AD8346 is supplied in a 16-lead TSSOP package, measur-
ing 6.5 × 5.1 × 1.1 mm. It is specified to operate over a
–40°C to +85°C temperature range and 2.7 V to 5.5 V supply
voltage range. The device is fabricated on Analog Devices’ high
performance 25 GHz bipolar silicon process.
REV. 0
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] World Wide Web Site: http://www.analog.com
Fax: [phone]
© Analog Devices, Inc., 1999