LTC1667_15 Datasheet, PDF (1/24 Pages) Linear Technology – 12-Bit, 14-Bit, 16-Bit, 50Msps DACs

FEATURES
s _{50Msps Update Rate}
s _{Pin Compatible 12-Bit, 14-Bit and 16-Bit Devices}
s _{High Spectral Purity: 87dB SFDR at 1MHz fOUT}
s _{5pV-s Glitch Impulse}
s _{Differential Current Outputs}
s _{20ns Settling Time}
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}
LTC1666/LTC1667/LTC1668
12-Bit, 14-Bit, 16-Bit,
50Msps DACs
DESCRIPTIO
The LTC^®1666/LTC1667/LTC1668 are 12-/14-/16-bit,
50Msps differential current output DACs implemented on
a high performance BiCMOS process with laser trimmed,
thin-film resistors. The combination of a novel current-
steering architecture and a high performance process
produces DACs with exceptional AC and DC performance.
The LTC1668 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 LTC1666/LTC1667/
LTC1668 can be configured to provide full-scale output
currents up to 10mA. The differential current outputs of
the DACs allow single-ended or true differential operation.
The –1V to 1V output compliance of the LTC1666/
LTC1667/LTC1668 allows the outputs to be connected
directly to external resistors to produce a differential out-
put voltage without degrading the converter’s linearity. Al-
ternatively, the outputs can be connected to the summing
junction of a high speed operational amplifier, or to a
transformer.
The LTC1666/LTC1667/LTC1668 are pin compatible and
are available in a 28-pin SSOP and are fully specified over
the industrial temperature range.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
LTC1668, 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
1666/7/8 TA01
52.3Ω
52.3Ω
+
V_OUT
1V_P-P
DIFFERENTIAL
–
LTC1668 SFDR vs f_OUT and f_CLOCK
100
5MSPS
90
25MSPS
80
50MSPS
70
60
50
0.1
DIGITAL AMPLITUDE = 0dBFS
1.0
10
f_OUT (MHz)
100
1666/7/8 G05
1