Dual, 16-Bit, 1000 MSPS,
TxDAC+ Digital-to-Analog Converter
AD9125
FEATURES
GENERAL DESCRIPTION
Flexible CMOS interface allows dual-word, word, or byte load
Single-carrier W-CDMA ACLR = 80 dBc at 122.88 MHz IF
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
Gain and phase adjustment for sideband suppression
Multichip synchronization interface
High performance, low noise PLL clock multiplier
Digital inverse sinc filter
Low power: 900 mW at 500 MSPS, full operating conditions
72-lead, exposed paddle LFCSP
The AD9125 is a dual, 16-bit, high dynamic range TxDAC+®
digital-to-analog converter (DAC) that provides a sample rate of
1000 MSPS, 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 allows programming/readback of many inter-
nal parameters. Full-scale output current can be programmed
over a range of 8.7 mA to 31.7 mA. The AD9125 comes in a
72-lead LFCSP.
APPLICATIONS
PRODUCT HIGHLIGHTS
Wireless infrastructure
W-CDMA, CDMA2000, TD-SCDMA, WiMAX, GSM, LTE
Digital high or low IF synthesis
Transmit diversity
1. Ultralow noise and intermodulation distortion (IMD)
enable high quality synthesis of wideband signals from
baseband to high intermediate frequencies.
Wideband communications: LMDS/MMDS, point-to-point
Cable modem termination systems
2. A proprietary DAC output switching technique enhances
dynamic performance.
3. The current outputs are easily configured for various
single-ended or differential circuit topologies.
4. The flexible CMOS digital interface allows the standard
32-wire bus to be reduced to a 16-wire bus.
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
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