The AD9851BRS is a highly integrated device that uses advancedDDS technology, coupled with an internal high-speed, highperformance D/A converter, and comparator, to form a digitally-programmablefrequency synthesizer and clock generatorfunction. When referenced to an accurate clock source, theAD9851BRS generates a stable frequency and phase-programmabledigitized analog output sinewave. This sinewave can be useddirectly as a frequency source, or internally converted to a squarewave for agile-clock generator applications.
The AD9851'sinnovative high-speed DDS core provides a 32-bit frequencytuning word, which results in an output tuning resolution of 40milli-Hertz, for a 180 MHz reference clock. The AD9851contains a unique X6 reference clock multiplier circuit thatobviates the need for a high-speed reference oscillator. The 6XPLL multiplier has minimal impact on SFDR and phase noisecharacteristics. The device provides 5-bits of digitally-controlledphase modulation which enables phase shifting of its output inincrements of 180°, 90°, 45°, 22.5°, 11.25°, and any combinationthereof.
Feature
- 180 MHz Clock Rate with Selectable 6x Reference Clock Multiplier
- On-Chip High Performance 10-Bit DAC and High Speed Comparator with Hysteresis
- SFDR >43 dB @ 70 MHz AOUT
- 32-Bit Frequency Tuning Word
- Simplified Control Interface: Parallel or Serial Asynchronous Loading Format
- 5-Bit Phase Modulation and Offset Capability
- Comparator Jitter <80 ps p-p @ 20 MHz
- 2.7 V to 5.25 V Single-Supply Operation
- Low Power: 555 mW @ 180 MHz
- Power-Down Function, 4 mW @ 2.7V
- Ultrasmall 28-Lead SSOP Packaging
