AD9851BRSZ

Description

IC DDS / DAC SYNTHESIZER 28SSOP

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 func- tion. 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 0.04 Hz with a 180 MHz system clock. The AD9851 contains a unique 6 REFCLK Multiplier circuit that eliminates the need for a high speed reference oscillator. The 6 REFCLK Multiplier has minimal impact on SFDR and phase noise char- acteristics. 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, 6 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 break- through level of functionality on just 555 mW of power dissipation (5 V supply), at the maximum clock rate of 180 MHz. 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°C to +85°C at >3.0 V supply voltage. Below 3.0 V, the specifications apply over the commercial temperature range of 0°C to 85°C.

Specifications

Alternate Descriptions