a
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
APPLICATIONS
Digital Communications
Direct Digital Synthesis
Waveform Reconstruction
High Speed Imaging
5 MHz–65 MHz HFC Upstream Path
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
CLOCK
TTL
DRIVE
LOGIC
DECODERS
AND
DRIVERS
10-Bit, 170 MSPS
D/A Converter
AD9731
FUNCTIONAL BLOCK DIAGRAM
ANALOG
RETURN
REGISTER
SWITCH
NETWORK
IOUT
IOUT
REF IN
CONTROL
AMP
INTERNAL VOLTAGE
REFERENCE
R
SET
DIGITAL DIGITAL ANALOG
–V
S
+V
S
–V
S
AMP OUT
REF OUT
CONTROL
AMP IN
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 communi-
cations 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 basestation and high volume subscriber-
end markets has created a demand for excellent DAC perfor-
mance delivered at reduced levels of power dissipation and cost.
The AD9731 is the answer to that demand.
Optimized for direct digital synthesis (DDS) waveform recon-
struction, 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 struc-
ture, 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. A
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
World Wide Web Site: http://www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 1999
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