Dual, 16-Bit, 1200 MSPS,
TxDAC+® Digital-to-Analog Converter
AD9122
FEATURES
GENERAL DESCRIPTION
Flexible LVDS interface allows word, byte, or nibble load
Single-carrier W-CDMA ACLR = 82 dBc @ 122.88 MHz IF
The AD9122 is a dual 16-bit, high dynamic range, digital-to-
analog converter (DAC) that provides a sample rate of 1200 MSPS,
Analog output: adjustable 8.7 mA to 31.7 mA, RL = 25 Ω to 50 Ω
Novel 2×/4×/8× interpolator/complex modulator allows
carrier placement anywhere in the DAC bandwidth
Digital gain and phase adjustment for sideband suppression
Multiple chip synchronization interfaces
High performance, low noise PLL clock multiplier
Digital inverse sinc filter
Flexible LVDS interface allows word, byte, or nibble load
Low power: 1.5 W @ 1.2 GSPS, 800 mW @ 500 MSPS, full
operating conditions
permitting a multicarrier generation up to the Nyquist frequency.
It includes features optimized for direct conversion transmit
applications, including complex digital modulation, and gain and
offset compensation. The DAC outputs are optimized to interface
seamlessly with analog quadrature modulators, such as the
ADL537x F-MOD series from Analog Devices, Inc. A 4-wire
serial port interface provides for programming/readback of many
internal parameters. Full-scale output current can be programmed
over a range of 8.7 mA to 31.7 mA. The AD9122 comes in a
72-lead LFCSP.
72-lead, exposed paddle LFCSP
PRODUCT HIGHLIGHTS
1. Ultralow noise and intermodulation distortion (IMD)
enable high quality synthesis of wideband signals from
baseband to high intermediate frequencies.
2. A proprietary DAC output switching technique enhances
dynamic performance.
APPLICATIONS
Wireless infrastructure
W-CDMA, CDMA2000, TD-SCDMA, WiMAX, GSM, LTE
Digital high or low IF synthesis
Transmit diversity
Wideband communications: LMDS/MMDS, point-to-point
3. The current outputs are easily configured for various
single-ended or differential circuit topologies.
4. Flexible LVDS digital interface allows the standard 32-wire
bus to be reduced to ½ or ¼ of the width.
TYPICAL SIGNAL CHAIN
COMPLEX BASEBAND
DC
COMPLEX IF
RF
f
LO – f
IF
IF
I DAC
2
2
2/4
2/4
SIN
DIGITAL
ANTIALIASING
FILTER
PA
BASEBAND
AQM
LO
PROCESSOR
COS
Q DAC
NOTES
1. AQM = ANALOG QUADRATURE MODULATOR.
Figure 1.
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 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.
Trademarks and registeredtrademarks arethe property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
www.analog.com
©2009 Analog Devices, Inc. All rights reserved.