250 MHz–1000 MHz
Quadrature Modulator
a
AD8345
FEATURES
FUNCTIONAL BLOCK DIAGRAM
250 MHz–1000 MHz Operating Frequency
+2.5 dBm P1 dB @ 800 MHz
–155 dBm/Hz Noise Floor
0.5 Degree RMS Phase Error (IS95)
0.2 dB Amplitude Balance
Single 2.7 V–5.5 V Supply
Pin-Compatible with AD8346
16-Lead Exposed Paddle TSSOP Package
AD8345
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
QBBP
QBBN
COM3
COM3
VPS2
IBBP
IBBN
COM3
COM1
LOIN
+
APPLICATIONS
PHASE
SPLITTER
VOUT
COM2
COM3
Cellular Communication Systems
W-CDMA/CDMA/GSM/PCS/ISM Transceivers
Fixed Broadband Access Systems LMDS/MMDS
Wireless LAN
LOIP
VPS1
ENBL
BIAS
Wireless Local Loop
Digital TV/CATV Modulators
Single Sideband Upconverter
PRODUCT DESCRIPTION
APPLICATIONS
The AD8345 is a silicon RFIC quadrature modulator, designed
for use from 250 MHz to 1000 MHz. Its excellent phase accu-
racy and amplitude balance enable the high performance direct
modulation of an IF carrier.
The AD8345 Modulator can be used as the IF transmit modu-
lator in digital communication systems such as GSM and PCS
transceivers. It can also directly modulate an LO signal to
produce QPSK and various QAM formats for 900 MHz com-
munication systems as well as digital TV and CATV systems.
The AD8345 accurately splits the external LO signal into two
quadrature components through the polyphase phase-splitter
network. The two I and Q LO components are mixed with the
baseband I and Q differential input signals. Finally, the outputs
of the two mixers are combined in the output stage to provide a
single-ended 50 Ω drive at VOUT.
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 AD8345 Modulator is supplied in a 16-lead TSSOP pack-
age with exposed paddle. Its performance is specified over a
–40°C to +85°C temperature range. This device is fabricated on
Analog Devices’ advanced silicon bipolar 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, norforanyinfringementsofpatentsorotherrightsofthirdpartiesthat
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: 781/329-4700
Fax: 781/326-8703
www.analog.com
© Analog Devices, Inc., 2001