DAC908
8
0
9
C
A
D
SBAS109B – JUNE 2003
TM
8-Bit, 165MSPS
DIGITAL-TO-ANALOG CONVERTER
FEATURES
● SINGLE +5V OR +3V OPERATION
APPLICATIONS
● MEDICAL INSTRUMENTATION
Ultrasound (DBF)
●
HIGH SFDR: 5.04MHz Output at 100MSPS: 67dBc
● VIDEO, DIGITAL TV
● LOW GLITCH: 3pV-s
● WAVEFORM GENERATION
● LOW POWER: 170mW at +5V
Direct Digital Synthesis (DDS)
● INTERNAL REFERENCE:
Optional Ext. Reference
Adjustable Full-Scale Range
Multiplying Option
Arbitrary Waveform Generation (ARB)
● TEST INSTRUMENTATION
● COMMUNICATIONS
For noncontinuous operation of the DAC908, a power-down mode
results in only 45mW of standby power.
DESCRIPTION
The DAC908 is a high-speed, Digital-to-Analog Converter (DAC)
offering an 8-bit resolution option within the SpeedPlus family of
high-performance converters. Featuring pin compatibility among
family members, the DAC900, DAC902, and DAC904 provide a
component selection option to an 10-, 12-, and 14-bit resolution,
respectively. All models within this family of DACs support update
rates in excess of 165MSPS with excellent dynamic performance,
and are especially suited to fulfill the demands of a variety of
applications.
The DAC908 comes with an integrated 1.24V bandgap reference
and edge-triggered input latches, offering a complete converter
solution. Both +3V and +5V CMOS logic families can be inter-
faced to the DAC908.
The reference structure of the DAC908 allows for additional
flexibility by utilizing the on-chip reference, or applying an exter-
nal reference. The full-scale output current can be adjusted over a
span of 2mA to 20mA, with one external resistor, while maintain-
ing the specified dynamic performance.
The advanced segmentation architecture of the DAC908 is opti-
mized to provide a high Spurious-Free Dynamic Range (SFDR) for
single-tone, as well as for multi-tone signals—essential when used
for the transmit signal path of communication systems.
The DAC908 is available in the SO-28 and TSSOP-28 packages.
+VA
BW
+VD
DAC908
The DAC908 has a high impedance (200kΩ) current output with a
nominal range of 20mA and an output compliance of up to 1.25V.
The differential outputs allow for both a differential or single-
ended analog signal interface. The close matching of the current
outputs ensures superior dynamic performance in the differential
configuration, which can be implemented with a transformer.
IOUT
IOUT
BYP
LSB
Switches
FSA
Current
Sources
REFIN
Segmented
Switches
INT/EXT
Utilizing a small geometry CMOS process, the monolithic DAC908
can be operated on a wide, single-supply range of +2.7V to +5.5V.
Its low power consumption allows for use in portable and battery-
operated systems. Further optimization can be realized by lowering
the output current with the adjustable full-scale option.
Latches
PD
+1.24V Ref.
8-Bit Data Input
D7...D0
AGND
CLK
DGND
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Copyright © 2002-2003, Texas Instruments Incorporated
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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