AD9742 Datasheet, PDF (1/20 Pages) Analog Devices – 12-Bit, 165 MSPS TxDAC D/A Converter

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FEATURES
High Performance Member of Pin-Compatible
TxDAC Product Family
Excellent Spurious-Free Dynamic Range Performance
SNR @ 5 MHz Output, 125 MSPS: 73 dB
Two’s Complement or Straight Binary Data Format
Differential Current Outputs: 2 mA to 20 mA
Power Dissipation: 135 mW @ 3.3 V
Power-Down Mode: 15 mW @ 3.3 V
On-Chip 1.20 V Reference
CMOS-Compatible Digital Interface
Package: 28-Lead SOIC and TSSOP Packages
Edge-Triggered Latches
APPLICATIONS
Wideband Communication Transmit Channel:
Direct IF
Base Stations
Wireless Local Loop
Digital Radio Link
Direct Digital Synthesis (DDS)
Instrumentation
12-Bit, 165 MSPS
TxDAC^® D/A Converter
AD9742^*
FUNCTIONAL BLOCK DIAGRAM
3.3V
0.1␮F
R_{SET 3.3V}
CLOCK
REFLO
+1.20V REF
REFIO
FS ADJ
150pF
AVDD ACOM
CURRENT
SOURCE
ARRAY
AD9742
DVDD
DCOM
SEGMENTED
SWITCHES
LSB
SWITCHES
IOUTA
IOUTB
CLOCK
LATCHES
MODE
DIGITAL DATA INPUTS (DB11–DB0)
SLEEP
PRODUCT DESCRIPTION
The AD9742 is a 12-bit resolution, wideband, third generation
member of the TxDAC series of high-performance, low power
CMOS digital-to-analog converters (DACs). The TxDAC family,
consisting of pin-compatible 8-, 10-, 12-, and 14-bit DACs, is
specifically optimized for the transmit signal path of communica-
tion systems. All of the devices share the same interface options,
small outline package, and pinout, providing an upward or down-
ward component selection path based on performance, resolution,
and cost. The AD9742 offers exceptional ac and dc performance
while supporting update rates up to 165 MSPS.
The AD9742’s low power dissipation makes it well suited for
portable and low power applications. Its power dissipation can be
further reduced to a mere 60 mW with a slight degradation in
performance by lowering the full-scale current output. Also, a
power-down mode reduces the standby power dissipation to
approximately 15 mW. A segmented current source architecture
is combined with a proprietary switching technique to reduce
spurious components and enhance dynamic performance. Edge-
triggered input latches and a 1.2 V temperature compensated
band gap reference have been integrated to provide a complete
monolithic DAC solution. The digital inputs support 3 V CMOS
logic families.
TxDAC is a registered trademark of Analog Devices, Inc.
* Protected by U.S. Patent Numbers 5568145, 5689257, and 5703519.
PRODUCT HIGHLIGHTS
1. The AD9742 is the 12-bit member of the pin compatible
TxDAC family that offers excellent INL and DNL
performance.
2. Data input supports two’s complement or straight binary
data coding.
3. High-speed, single-ended CMOS clock input supports
165 MSPS conversion rate.
4. Low power: Complete CMOS DAC function operates on
135 mW from a 3.0 V to 3.6 V single supply. The DAC full-
scale current can be reduced for lower power operation, and
a sleep mode is provided for low power idle periods.
5. On-chip voltage reference: The AD9742 includes a 1.2 V
temperature-compensated band gap voltage reference.
6. Industry standard 28-lead SOIC and TSSOP packages.
REV. 0
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