Analog Devices Inc. AD9238BSTZRL-20

Overview

AD9238BSTZRL-20 from Analog Devices is a dual-channel, 12-bit, 20 MSPS analog-to-digital converter (ADC) fabricated in advanced CMOS, featuring integrated sample-and-hold amplifiers, on-chip voltage reference, and differential input with 500 MHz bandwidth. It operates from a single 3 V supply (2.7–3.6 V), delivers 70 dB SNR and 86 dBc SFDR at 2.4 MHz input, and supports offset binary or twos complement output formats for ultrasound and IF-sampling receiver applications.

For engineers reviewing the AD9238BSTZRL-20 datasheet, AD9238BSTZRL-20 pinout, AD9238BSTZRL-20 application, or AD9238BSTZRL-20 equivalent, key selection considerations include its 20 MSPS sampling rate, dual-channel crosstalk immunity (>85 dB), clock duty cycle stabilizer, flexible 1–2 V_p-p analog input range, and LQFP-64 industrial-grade packaging.

Technical Context

The AD9238BSTZRL-20 implements a multistage differential pipelined ADC architecture with output error correction logic to guarantee 12-bit accuracy and no missing codes across −40°C to +85°C. Its dual independent sample-and-hold amplifiers support simultaneous sampling of two analog channels with exceptional channel isolation.

It features dual single-ended clock inputs (CLK_A/CLK_B), a clock duty cycle stabilizer (DCS) that maintains performance over wide duty cycle variation, and configurable data output muxing via MUX_SELECT. Digital outputs are CMOS-compatible with DRVDD-supplied levels and programmable format (DFS pin).

Key Specifications

Pinout & Package

The AD9238BSTZRL-20 is packaged in a Pb-free, 64-lead LQFP (10 mm × 10 mm, 0.5 mm pitch) with exposed thermal pad connected to AGND. Pin 1 identifier located at top-left corner; AGND pins distributed across package for low-impedance analog grounding.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel ADC applications.

Compared with AD9238BSTZRL-20, the -40 variant offers doubled throughput at modest power cost, while AD9248BSTZRL-20 trades 2 bits of resolution for improved DC linearity-making the -20 optimal for cost-sensitive, medium-bandwidth communications and portable test gear where 12-bit dynamic fidelity is sufficient.

Availability

AD9238BSTZRL-20 is available at Aetrix Electronics and suitable for ultrasound beamforming, IF sampling receivers, and battery-powered scopemeters requiring stable component supply, long-term industrial temperature support (−40°C to +85°C), and RoHS-compliant LQFP packaging.

Supply support for AD9238BSTZRL-20 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 digital signal processing semiconductors, headquartered in Norwood, MA, with design centers worldwide and a legacy of precision data conversion innovation since 1965.

The AD9238 product line delivers dual-channel, low-power, high-speed ADCs optimized for medical imaging, wireless infrastructure, and portable test equipment-designed to replace discrete ADC + reference + driver solutions with integrated, production-ready signal chains.

FAQ

What is the maximum sampling rate of the AD9238BSTZRL-20?

The AD9238BSTZRL-20 is a speed-graded variant rated for a maximum sampling rate of 20 MSPS. This is fixed by internal design and cannot be increased beyond specification-even with faster clock inputs-due to pipeline stage timing constraints and guaranteed AC performance validation at this rate. The AD9238BSTZRL-20 datasheet specifies 20 MSPS as the maximum conversion rate under all operating conditions.

Does the AD9238BSTZRL-20 support both offset binary and twos complement output formats?

Yes, the AD9238BSTZRL-20 supports both output formats. The DFS pin controls format selection: logic low configures offset binary (default), and logic high selects twos complement. This setting affects all 12-bit outputs (D0–D11) for both Channel A and Channel B simultaneously, and is latched on power-up or reset.

What is the purpose of the MUX_SELECT pin on the AD9238BSTZRL-20?

The MUX_SELECT pin enables or disables the internal data multiplexer. When logic low, the AD9238BSTZRL-20 outputs alternating Channel A and Channel B samples on the shared D0–D11 bus (time-multiplexed mode). When high, it disables multiplexing, allowing independent parallel access to both 12-bit buses-required for true simultaneous dual-channel capture in FPGA-based systems.

How does the clock duty cycle stabilizer (DCS) function in the AD9238BSTZRL-20?

The DCS circuit in the AD9238BSTZRL-20 actively corrects clock duty cycle distortion across 30–70% range, ensuring consistent aperture timing and minimizing jitter-induced SNR degradation. Enabled by tying the DCS pin high, it operates independently per channel (CLK_A/CLK_B) and maintains <0.5 ps rms aperture uncertainty even with highly asymmetric clocks-critical for IF sampling stability.

What package type is used for the AD9238BSTZRL-20?

The AD9238BSTZRL-20 uses a 64-lead LQFP (Leadless Quad Flat Package) with 10 mm × 10 mm body, 0.5 mm lead pitch, and exposed thermal pad. The "Z" in the part number denotes Pb-free LQFP packaging, and the "RL" suffix indicates tape-and-reel delivery. This package is specified for industrial temperature operation (−40°C to +85°C) and requires AGND connection to the exposed pad for thermal and noise performance.