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LTC1668

16-Bit, 50Msps DAC

February 2000

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50Msps Update Rate

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16-Bit Resolution

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Differential Current Outputs

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30ns Settling Time

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5pV-s Glitch Impulse

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Low Power: 180mW from

±5V Supplies

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TTL/CMOS (3.3V or 5V) Inputs

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Small Package: 28-Pin SSOP

The LTC

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.

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Cellular Base Stations

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Multicarrier Base Stations

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Wireless Communication

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Direct Digital Synthesis (DDS)

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xDSL Modems

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Arbitrary Waveform Generation

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Automated Test Equipment

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Instrumentation

16-Bit, 50Msps DAC

Final Electrical Specifications

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.

–

+

16-BIT

HIGH SPEED

DAC

2.5V

REFERENCE

–5V

CLOCK

INPUT

16-BIT DATA

INPUT

LADCOM

AGND DGND

CLK

DB15

DB0

1668 TA01

0.1

µF

LTC1668

5V

52.3

Ω

REFOUT

COMP1

COMP2

C2

0.1

µF

0.1

µF

C1

0.1

µF

2k

52.3

Ω

DIFFERENTIAL

+

–

0.1

µF

FREQUENCY (1.25MHz/DIV)

0.05

–45

–25

–5

1668 G01

–65

–85

–55

–35

–15

–75

–95

–105

6.3

12.55

AMPLITUDE = 0dBFS

= –8.5dBm

SFDR = 86dBc

Single Tone SFDR

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO