ADI AD9851BRSZ

The AD9851 is a highly integrated device that uses advanced DDS technology, coupled with an internal high speed, high performance D/A converter, and comparator, to form a digitally programmable frequency synthesizer and clock generator function. When referenced to an accurate clock source, the AD9851 generates a stable frequency and phase- programmable digitized analog output sine wave. This sine wave can be used directly as a frequency source, or internally converted to a square wave for agile- clock generator applications. The AD9851's innovative high speed DDS core accepts a 32- bit frequency tuning word, which results in an output tuning resolution of approximately 0.04Hz with a 180MHz system clock. The AD9851 contains a unique 6x REFCLK Multiplier circuit that eliminates the need for a high speed reference oscillator. The 6x REFCLK Multiplier has minimal impact on SFDR and phase noise characteristics. The AD9851 provides five bits of programmable phase modulation resolution to enable phase shifting of its output in increments of 11.25°. The AD9851 contains an internal high speed comparator that can be configured to accept the (externally) filtered output of the DAC to generate a low jitter output pulse. The frequency tuning, control, and phase modulation words are asynchronously loaded into the AD9851 via a parallel or serial loading format. The parallel load format consists of five iterative loads of an 8- bit control word (byte). The first 8- bit byte controls output phase, 6x REFCLK Multiplier, power- down enable and loading format; the remaining bytes comprise the 32- bit frequency tuning word. Serial loading is accomplished via a 40- bit serial data stream entering through one of the parallel input bus lines. The AD9851 uses advanced CMOS technology to provide this breakthrough level of functionality on just 535 mW of power dissipation (5 V supply), at the maximum clock rate of 180MHz. The AD9851 is available in a space- saving 28- lead SSOP, surface- mount package that is pin- for- pin compatible with the popular AD9850 125 MHz DDS. It is specified to operate over the extended industrial temperature range of - 40℃ to +85℃ at >3.0V supply voltage. Below 3.0V, the specifications apply over the commercial temperature range of 0℃ to 85℃.

• 180 MHz Clock Rate with Selectable 6× Reference Clock Multiplier
• On- Chip High Performance 10- Bit DAC and High Speed Comparator with Hysteresis
• OFDR >40 dB @ 70MHz
• 32- Bit Frequency Tuning Word
• Simplified Control Interface: Parallel or Serial
• Asynchronous Loading Format
• 5- Bit Phase Modulation and Offset Capability
• Comparator Jitter < 80 psₚ₋ₚ @ 20 MHz
• 2.7V to 5.25V Single Supply Operation
• Low Power: 555 mW @ 180 MHz
• Power- Down Function, 4mW @ 2.7V
• Ultrasmall 28- Lead SSOP Packaging

• Frequency/Phase- Agile Sine Wave Synthesis
• Clock Recovery and Locking Circuitry for Digital Communications
• Digitally Controlled ADC Encode Generator
• Agile Local Oscillator Applications in Communications
• Quadrature Oscillator
• CW,AM,FM,FSK,MSK Mode Transmitter