LTC1668 Datasheet, PDF (1/16 Pages) Linear Technology – 16-Bit, 50Msps DAC

FEATURES
s _{50Msps Update Rate}
s _{16-Bit Resolution}
s _{High Spectral Purity: 87dB SFDR at 1MHz fOUT}
s _{Differential Current Outputs}
s _{30ns Settling Time}
s _{5pV-s Glitch Impulse}
s _{Low Power: 180mW from ±5V Supplies}
s _{TTL/CMOS (3.3V or 5V) Inputs}
s _{Small Package: 28-Pin SSOP}
U
APPLICATIO S
s _{Cellular Base Stations}
s _{Multicarrier Base Stations}
s _{Wireless Communication}
s _{Direct Digital Synthesis (DDS)}
s _{xDSL Modems}
s _{Arbitrary Waveform Generation}
s _{Automated Test Equipment}
s _{Instrumentation}
Final Electrical Specifications
LTC1668
16-Bit, 50Msps DAC
February 2000
DESCRIPTIO
The LTC^®1668 is a 16-bit, 50Msps differential current
output DAC implemented on a high performance BiCMOS
process with laser trimmed, thin-film resistors. The com-
bination of a novel current-steering architecture and a
high performance process produces a DAC with excep-
tional AC and DC performance. This is the first 16-bit DAC
in the marketplace to exhibit an SFDR (spurious free
dynamic range) of 87dB for an output signal frequency of
1MHz.
Operating from ±5V supplies, the LTC1668 can be con-
figured to provide full-scale output currents up to 10mA.
The differential current outputs of the DAC allow single-
ended or true differential operation. The –1V to 1V output
compliance of the LTC1668 allows the outputs to be con-
nected directly to external resistors to produce a differ-
ential output voltage without degrading the converter’s
linearity. Alternatively, the outputs can be connected to the
summing junction of a high speed operational amplifier,
or to a transformer.
The LTC1668 is available in a 28-pin SSOP and is fully
specified over the industrial temperature range.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
16-Bit, 50Msps DAC
5V
0.1µF
0.1µF
R_SET
2k
C1
0.1µF
C2
0.1µF
REFOUT
2.5V
V_DD
REFERENCE
I_REFIN
LTC1668
COMP1
COMP2
V_SS
+
16-BIT
HIGH SPEED
–
DAC
AGND DGND CLK DB15 DB0
0.1µF
– 5V
CLOCK 16-BIT DATA
INPUT INPUT
I_{OUT A}
I_{OUT B}
LADCOM
1668 TA01
52.3Ω
52.3Ω
+
V_OUT
–
1V_P-P
DIFFERENTIAL
–5
–15
–25
–35
–45
–55
–65
–75
–85
–95
–105
0.05
Single Tone SFDR
f_CLOCK = 25Msps
f_OUT = 1.007MHz
AMPLITUDE = 0dBFS
= –8.5dBm
SFDR = 86dBc
6.3
FREQUENCY (1.25MHz/DIV)
12.55
1668 G01
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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