a
10-Bit, 170 MSPS
D/A Converter
AD9731
FEATURES
170 MSPS Update Rate
TTL/High Speed CMOS-Compatible Inputs
Wideband SFDR: 66 dB @ 2 MHz/50 dB @ 65 MHz
Pin-Compatible, Lower Cost Replacement for
Industry Standard AD9721 DAC
Low Power: 439 mW @ 170 MSPS
Fast Settling: 3.8 ns to 1/2 LSB
Internal Reference
Two Package Styles: 28-Lead SOIC and SSOP
OBS
APPLICATIONS
Digital Communications
Direct Digital Synthesis
Waveform Reconstruction
High Speed Imaging
5 MHz to 65 MHz HFC Upstream Path
FUNCTIONAL BLOCK DIAGRAM
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
ANALOG
RETURN
TTL
DRIVE
LOGIC
DECODERS
AND
DRIVERS
REGISTER
SWITCH
NETWORK
IOUT
IOUT
REF IN
CLOCK
CONTROL
AMP
OLE
GENERAL DESCRIPTION
The AD9731 is a 10-bit, 170 MSPS, bipolar D/A converter that is
optimized to provide high dynamic performance, yet offer lower
power dissipation and more economical pricing than afforded by
previous bipolar high performance DAC solutions. The AD9731
was designed primarily for demanding communications systems
applications where wideband spurious-free dynamic range (SFDR)
requirements are strenuous and could previously only be met by
using a high performance DAC such as the industry-standard
AD9721. The proliferation of digital communications into base
station and high volume subscriber-end markets has created a
demand for excellent DAC performance delivered at reduced
levels of power dissipation and cost. The AD9731 is the answer
to that demand.
INTERNAL VOLTAGE
REFERENCE
RSET
REF OUT
AMP OUT
CONTROL
AMP IN
DIGITAL DIGITAL ANALOG
+VS
–VS
–VS
TE
Optimized for direct digital synthesis (DDS) waveform reconstruction, the AD9731 provides 50 dB of wideband harmonic
suppression over a dc-to-65 MHz analog output bandwidth.
This signal bandwidth addresses the transmit spectrum in many
of the emerging digital communications applications where
signal purity is critical. Narrowband, the AD9731 provides an
SFDR of greater than 79 dB. This excellent wideband and
narrowband ac performance, coupled with a lower pricing structure,
make the AD9731 the optimum high performance DAC value.
The AD9731 is packaged in 28-lead SOIC (same footprint
as the industry-standard AD9721) and super space-saving
28-lead SSOP; both are specified to operate over the extended
industrial temperature range of –40∞C to +85∞C.
REV. B
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. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.
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© 2003 Analog Devices, Inc. All rights reserved.
