AD9830ASTZ

Overview

The AD9830ASTZ is a complete Direct Digital Synthesis (DDS) device integrating a numerically controlled oscillator, sine look-up table, and 10-bit digital-to-analog converter on a single CMOS chip. It supports clock rates up to 50 MHz with frequency accuracy of one part in 4 billion. The device features parallel loading via a microprocessor interface, phase and frequency modulation capabilities, and a power-down option. Operating on a +5 V supply, it consumes 250 mW and delivers a spurious-free dynamic range of 72 dB. The component is housed in a 48-pin QFP package.

Feature Summary

• Integrates a 32-bit phase accumulator, sine look-up table, and 10-bit DAC for direct waveform generation.
• Supports parallel data loading through a dedicated microprocessor interface for register updates.
• Provides internal modulation functions including phase shift keying and frequency shift keying.
• Includes an onboard voltage reference and full-scale current adjustment control.

Applications

• Direct Digital Synthesis tuning
• Digital demodulation systems
• Frequency shift keying (FSK) modulation
• Phase shift keying (PSK) modulation

Procurement Notes

Verify the specific suffix 'ASTZ' against the manufacturer's official documentation to confirm the industrial temperature grade (-40°C to +85°C) and lead-free packaging status. Ensure the parallel interface requirements match the system design, as this model does not support serial communication protocols found in other variants within the same product family.

Selection Notes

Select this component when a high-speed DDS solution with parallel interface compatibility is required. The 50 MHz maximum clock rate and 10-bit resolution are suitable for applications demanding precise frequency control. Consider the 48-pin QFP footprint during PCB layout planning to ensure adequate spacing for analog and digital ground separation.

Part Context

The AD9830 belongs to Analog Devices' series of complete DDS synthesizers. Unlike serial-interface models such as the AD9833 or AD9834, this variant utilizes a parallel bus for data transfer. It shares core architectural elements like the 32-bit phase accumulator with other members but differs in interface speed and pin count.

Replacement Considerations

The AD9831ASTZ offers similar functionality but operates with a lower maximum clock frequency of 25 MHz. Both devices utilize the 48-pin LQFP package and parallel interface, though electrical specifications and performance metrics differ significantly between the two models.

FAQ

How is the full-scale output current adjusted?

The full-scale current is determined by connecting an external resistor (RSET) between the FS ADJUST pin and AGND. The relationship is defined by IOUTFULL-SCALE = 16 * VREFIN / RSET.

What is the purpose of the FSELECT pin?

The FSELECT pin controls which frequency register (FREQ0 or FREQ1) is used by the phase accumulator. It allows for frequency switching without phase discontinuity.

How many phase registers are available?

The AD9830 contains four 12-bit phase offset registers (PHASE0 through PHASE3), selectable via the PSEL0 and PSEL1 inputs.