AD9775EB AD [Analog Devices], AD9775EB Datasheet - Page 2

• Manufacturer Part Number: AD9775EB
• Description: 14-Bit, 160 MSPS 2X/4X/8X Interpolating Dual TxDAC+ D/A Converter
• Manufacturer: AD [Analog Devices]

AD9775
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errors associated with analog quadrature modulators. The 6 dB
of gain adjustment range can also be used to control the output
power level of each DAC.
The AD9775 features the ability to perform f
digital modulation and image rejection when combined with an
analog quadrature modulator. In this mode, the AD9775 ac-
cepts I and Q complex data (representing a single or multicarrier
waveform), generates a quadrature modulated IF signal along with
its orthogonal representation via its dual DACs, and presents
these two reconstructed orthogonal IF carriers to an analog
quadrature modulator to complete the image rejection
upconversion process. Another digital modulation mode (i.e.,
the Direct IF Mode) allows the original baseband signal repre-
sentation to be frequency translated such that pairs of images fall
at multiples of one-half the DAC update rate.
The AD977x family includes a flexible clock interface accepting
differential or single-ended sine wave or digital logic inputs. An
internal PLL clock multiplier is included and generates the
necessary on-chip high frequency clocks. It can also be disabled
to allow the use of a higher performance external clock source.
An internal programmable divider simplifies clock generation in
the converter when using an external clock source. A flexible data
input interface allows for straight binary or two’s complement
formats and supports single-port interleaved or dual-port data.
Dual high performance DAC outputs provide a differential
current output programmable over a 2 mA to 20 mA range. The
AD9775 is manufactured on an advanced 0.35 micron CMOS
process, operates from a single supply of 3.1 V to 3.5 V, and
consumes 1.2 W of power.
Targeted at wide dynamic range, multicarrier and multistandard
systems, the superb baseband performance of the AD9775 is ideal
for wideband CDMA, multicarrier CDMA, multicarrier TDMA,
multicarrier GSM, and high performance systems employing
high order QAM modulation schemes. The image rejection
feature simplifies and can help to reduce the number of signal
band filters needed in a transmit signal chain. The direct IF
mode helps to eliminate a costly mixer stage for a variety of
communications systems.
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PRODUCT HIGHLIGHTS
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10. Flexible clock input with single-ended or differential input,
11. Low power: Complete CMOS DAC operates on 1.2 W
12. On-chip voltage reference: The AD9775 includes a 1.20 V
13. 80-lead thermally enhanced TQFP.
The AD9775 is the 14-bit member of the AD977x pin-
compatible, high performance, programmable 2×/4×/8×
interpolating TxDAC+ family.
Direct IF transmission capability for 70 MHz + IFs through
a novel digital mixing process.
f
selectable image rejection to simplify/remove cascaded
SAW filter stages.
A 2×/4×/8× user-selectable interpolating filter eases data
rate and output signal reconstruction filter requirements.
User-selectable two’s complement/straight binary data
coding.
User-programmable channel gain control over 1 dB
range in 0.01 dB increments.
User-programmable channel offset control ± 10% over
the FSR.
Ultra high speed 400 MSPS DAC conversion rate.
Internal clock divider provides data rate clock for easy
interfacing.
CMOS, or 1 V p-p LO sine wave input capability.
from a 3.1 V to 3.5 V single supply. The 20 mA full-scale
current can be reduced for lower power operation and
several sleep functions are provided to reduce power dur-
ing idle periods.
temperature compensated band gap voltage reference.
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