Analog Devices Inc. AD9850BRS-REEL

Overview

AD9850BRS-REEL from Analog Devices is a CMOS, 125 MHz complete direct digital synthesis (DDS) synthesizer IC integrating a 10-bit DAC, high-speed comparator, and 32-bit frequency tuning engine. It generates spectrally pure, digitally programmable sine waves up to 62.5 MHz and low-jitter square waves for agile clock generation. Key confirmed specs: 32-bit tuning resolution (0.0291 Hz @ 125 MHz CLKIN), DAC SFDR >50 dBc @ 40 MHz AOUT, 28-pin SSOP package, –40°C to +85°C operation.

For engineers reviewing the AD9850BRS-REEL datasheet, AD9850BRS-REEL pinout, AD9850BRS-REEL application, or AD9850BRS-REEL equivalent, this page delivers verified functional identity, exact pin roles, real-world timing behavior (e.g., 18-cycle frequency update latency), DAC output compliance (1.5 V), and comparator jitter (80 ps p-p), all critical for DDS-based signal source design and clock recovery systems.

Technical Context

The AD9850BRS-REEL implements a numerically controlled oscillator (NCO) with a 32-bit phase accumulator and proprietary amplitude/cosine conversion algorithm using a reduced-ROM lookup table. Its DDS core accepts parallel (5×8-bit) or serial (40-bit) tuning word loading, with asynchronous frequency/phase updates triggered by FQ_UD.

It features dual power domains (AVDD/DVDD), differential DAC outputs (IOUT/IOUTB), and comparator inputs (VINP/VINN) supporting flexible analog interface configurations. The on-chip comparator converts filtered DAC output to TTL/CMOS square wave with 5.5 ns propagation delay (5 V) and 80 ps output jitter, enabling precise clock generation without external logic.

Key Specifications

Pinout & Package

AD9850BRS-REEL is housed in a 28-lead Shrink Small Outline Package (SSOP), RS-28 package option, with exposed pad not present and surface-mount mounting.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DDS synthesizer applications.

Compared with AD9851ASTZ and AD9910BCPZ, the AD9850BRS-REEL delivers proven 125 MHz DDS performance in a compact SSOP package with dual parallel/serial control-making it ideal for industrial clocking and agile LO applications where simplicity, reliability, and footprint matter more than extreme bandwidth or resolution.

Availability

AD9850BRS-REEL is available at Aetrix Electronics and suitable for frequency-agile local oscillator design, digital communications clock recovery, and programmable ADC encode generation requiring stable component supply across industrial temperature ranges.

Supply support for AD9850BRS-REEL includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and DSP technologies, serving industrial, communications, and automotive markets since 1965.

The AD9850 belongs to Analog Devices' Direct Digital Synthesis (DDS) product line, designed specifically for applications demanding digitally programmable, phase-continuous, low-jitter frequency sources-especially in communications infrastructure, test instrumentation, and agile RF systems.

FAQ

What is the maximum output frequency achievable with the AD9850BRS-REEL?

The AD9850BRS-REEL supports output frequencies up to one-half the reference clock frequency. With its rated 125 MHz clock input (5 V supply), the maximum fundamental output frequency is 62.5 MHz. Higher frequencies appear as aliased images per Nyquist theory, so practical use limits output to <33% of CLKIN (e.g., ≤41 MHz) to avoid in-band spurs without aggressive filtering. The AD9850BRS-REEL's architecture ensures phase-continuous transitions even at these upper limits.

How does the AD9850BRS-REEL achieve 0.0291 Hz frequency resolution?

The AD9850BRS-REEL achieves 0.0291 Hz resolution using its 32-bit frequency tuning word and a 125 MHz reference clock, per the formula fOUT = (∆Phase × CLKIN) / 2³². With ∆Phase ranging from 0 to 2³²−1, the smallest nonzero step yields 125,000,000 / 4,294,967,296 ≈ 0.0291 Hz. This resolution is inherent to the AD9850BRS-REEL's NCO architecture and requires no external interpolation or dithering.

Can the AD9850BRS-REEL operate from a 3.3 V supply?

Yes, the AD9850BRS-REEL supports single-supply operation at either 3.3 V or 5 V. At 3.3 V, it operates up to 110 MHz CLKIN (vs. 125 MHz at 5 V), dissipates 155 mW typical at 110 MHz, and maintains full functionality-including DAC output, comparator operation, and parallel/serial programming. Logic thresholds adjust accordingly (e.g., Logic 1 = 2.4 V min at 3.3 V), and all timing parameters remain valid per the datasheet's VI test level.

What is the purpose of the RSET pin on the AD9850BRS-REEL?

The RSET pin (Pin 12) sets the full-scale output current of the AD9850BRS-REEL's integrated 10-bit DAC via an external resistor to ground. The relationship is IOUT = 32 × (1.248 V / RSET); using 3.9 kΩ yields 10.24 mA full scale. This allows scaling DAC output drive strength and optimizing SFDR vs. power trade-offs. RSET also affects DAC gain error and temperature coefficient, making precision resistor selection critical for stable amplitude accuracy in the AD9850BRS-REEL.

Does the AD9850BRS-REEL support phase modulation, and how is it implemented?

Yes, the AD9850BRS-REEL provides 5-bit digital phase modulation, enabling discrete phase shifts of 11.25°, 22.5°, 45°, 90°, or 180°, plus any combination thereof. Phase modulation is encoded in the most significant bits of the first parallel load byte (W0[4:0]) or bits W39–W35 in serial mode. When applied, the AD9850BRS-REEL adds the selected offset to the phase accumulator output before cosine conversion-enabling simple BPSK or QPSK modulation without external circuitry.