AD9835BRU-REEL7

Overview

The AD9835BRU-REEL7 is a direct digital synthesizer (DDS) waveform generator manufactured by Analog Devices Inc. It integrates a numerically controlled oscillator, a cosine lookup table, and a 10-bit digital-to-analog converter on a single CMOS chip. The device supports clock rates up to 50 MHz with an update rate of 50 MSPS. It features a 32-bit phase accumulator for high frequency accuracy, controllable to one part in 4 billion. The component operates on a 5 V power supply, consuming 200 mW during normal operation and reducing to 1.75 mW in power-down mode. It is housed in a 16-lead TSSOP package and functions within a temperature range of −40°C to +85°C.

Feature Summary

• Integrates a numerically controlled oscillator with a 32-bit phase accumulator and a built-in cosine lookup table for precise signal generation.
• Includes a 10-bit high-impedance current output DAC with adjustable full-scale current via an external resistor.
• Supports serial loading of frequency and phase registers through a standard three-wire interface.
• Provides dedicated hardware inputs for selecting between two frequency registers and four phase offset registers.

Applications

• Frequency stimulus and waveform generation
• Frequency phase tuning and modulation in communications systems
• Liquid and gas flow measurement instrumentation
• Proximity, motion, and defect detection sensory applications

Procurement Notes

Verify the specific ordering suffix RU-REEL7 against the manufacturer's official documentation to confirm reel packaging specifications. Ensure the B version industrial temperature rating matches the operational environment requirements. Cross-reference the pinout configuration with the target PCB layout to guarantee compatibility with the 16-lead TSSOP footprint.

Selection Notes

Select this component when a low-power, single-chip DDS solution is required for generating sine waves up to 25 MHz. Consider the 10-bit resolution and dynamic performance metrics if harmonic distortion and noise floor are critical constraints. Evaluate the serial interface timing requirements against the host microprocessor capabilities to ensure reliable data transfer.

Part Context

This part belongs to the AD9835 family of direct digital synthesizers from Analog Devices. It is designed as a complete system-on-a-chip solution for RF and baseband applications. The BRU variant specifically denotes the industrial temperature grade and TSSOP packaging, distinguishing it from other thermal or package options within the same functional series.

Replacement Considerations

Consult the Analog Devices DDS product selector guide for alternative parts with similar clock speeds or resolution. Verify pin compatibility and register mapping before substituting with other DDS models to avoid redesigning the serial interface logic.

FAQ

How is the full-scale output current adjusted?

The full-scale output current is determined by connecting an external resistor (RSET) between the FS_ADJUST pin and AGND. The relationship is defined by the formula IOUT_FULL_SCALE = 12.5 × V_REFIN / R_SET.

What is the maximum output frequency capability?

While the device supports a master clock (MCLK) up to 50 MHz, the usable output frequency is typically limited to approximately 25 MHz due to Nyquist sampling constraints and filter characteristics.

Can the device perform phase modulation?

Yes, the AD9835 includes four 12-bit phase offset registers that can be selected via PSEL0 and PSEL1 pins or bits to add phase offsets to the phase accumulator output.