Analog Devices Inc. AD9238BST-40

Overview

AD9238BST-40 from Analog Devices is a dual, 12-bit, 40 MSPS analog-to-digital converter with differential input, 500 MHz analog bandwidth, and integrated voltage reference. It operates from a single 3 V supply (2.7 V–3.6 V), delivers 70.2 dB SNR and 80.5 dBc SFDR at 9.7 MHz input, and targets IF sampling in wireless receivers and ultrasound front-ends.

For engineers reviewing the AD9238BST-40 datasheet, AD9238BST-40 pinout, AD9238BST-40 application, or AD9238BST-40 equivalent, this page provides verified technical context, real-world design meaning for key specs, validated pin functions, confirmed alternatives, and supply support for industrial and medical instrumentation designs.

Technical Context

The AD9238BST-40 uses a multistage differential pipelined architecture with output error correction logic to guarantee 12-bit accuracy and no missing codes across −40°C to +85°C. Its dual sample-and-hold amplifiers support flexible analog input ranges (1 V_p-p or 2 V_p-p) and enable high-fidelity simultaneous sampling of two channels.

Dual independent clock inputs (CLK_A/CLK_B) control conversion cycles, and the integrated duty cycle stabilizer maintains performance over wide clock duty cycle variation. Digital outputs are configurable as offset binary or twos complement, with multiplexed data output mode enabling single-port operation.

Key Specifications

Pinout & Package

AD9238BST-40 is packaged in a 64-lead LQFP (Leadless Quad Flat Package) with exposed pad requiring connection to AGND. Pinout is fully defined per Analog Devices Rev. D datasheet Figure 3 and Table 6.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD9238BST-40, AD9248BST-40 trades 2 extra bits for 27% higher power and reduced wideband SFDR, while ADS5272IPFP sacrifices 2.7 dB SNR and integrated reference to reduce size and cost-making AD9238BST-40 optimal for balanced IF-sampling systems needing self-contained, low-crosstalk dual conversion.

Availability

AD9238BST-40 is available at Aetrix Electronics and suitable for ultrasound beamforming, IF sampling receivers, and battery-powered scopemeters requiring stable component supply across extended product lifecycles.

Supply support for AD9238BST-40 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, automotive, and healthcare markets since 1965.

The AD9238 belongs to Analog Devices' high-speed data converter product line, designed specifically for dual-channel, medium-speed digitization in medical imaging, wireless infrastructure, and portable test equipment where channel matching, low power, and integrated references are critical.

FAQ

What is the maximum analog input frequency supported by the AD9238BST-40?

The AD9238BST-40 features a 500 MHz analog input bandwidth, enabling faithful digitization of signals up to 200 MHz using undersampling techniques. At Nyquist-limited operation (20 MHz), it achieves 70.2 dB SNR and 80.5 dBc SFDR per channel-verified in datasheet Figure 14 and Table 2 for f_IN = 9.7 MHz and 32.5 MHz conditions. The 500 MHz bandwidth is measured differentially and applies to both channels independently.

Does the AD9238BST-40 require an external voltage reference?

No, the AD9238BST-40 integrates a precision 1.0 V (or 0.5 V) voltage reference with ±35 mV output error and 0.8 mV load regulation at 1 mA. The SENSE pin configures reference mode, and REFT/REFB pins provide differential reference connections per channel. External reference is optional only if higher accuracy or custom voltage is needed-confirmed in datasheet Sections "Internal Voltage Reference" and Figure 1.

How does the duty cycle stabilizer (DCS) function in the AD9238BST-40?

The DCS circuit in AD9238BST-40 corrects wide variations in input clock duty cycle (e.g., 30%–70%) to maintain consistent aperture jitter and preserve SNR/SFDR performance. When DCS is enabled (DCS pin tied high), SINAD remains stable within ±0.5 dB across 40%–60% duty cycle-demonstrated in Figure 24. This eliminates need for external clock conditioning in systems with imperfect clock sources.

Can the AD9238BST-40 operate with a single-ended analog input?

Yes-the AD9238BST-40 supports single-ended analog inputs via AC-coupled configuration using one input pin referenced to common-mode voltage (typically AVDD/2). The datasheet specifies flexible input structure (Section "Analog Input") and confirms single-ended use cases in General Description: "wide bandwidth, differential SHA allows for … single-ended applications." Performance metrics assume differential drive, but layout guidelines accommodate single-ended adaptation.

What is the pipeline latency of the AD9238BST-40, and why does it matter?

The AD9238BST-40 has a fixed 7-cycle pipeline latency from CLK edge to valid output data-specified in Table 4 and Figure 2. This deterministic delay enables precise timing alignment in FPGA-based processing pipelines, especially for dual-channel phase-coherent applications like I/Q demodulation or beamforming. Latency is independent of sample rate and input frequency, simplifying synchronization logic.