Analog Devices Inc. AD9238BSTZ-20

Overview

AD9238BSTZ-20 from Analog Devices is a dual-channel, 12-bit, 20 MSPS analog-to-digital converter (ADC) with differential input architecture, 500 MHz analog input bandwidth, and integrated voltage reference. It operates from a single 3 V supply (2.7–3.6 V), delivers 70.4 dB SNR at 2.4 MHz input, and supports offset binary or twos complement output formats. It is used in ultrasound front-ends and handheld scopemeters requiring low-power, high-isolation sampling.

For engineers reviewing the AD9238BSTZ-20 datasheet, AD9238BSTZ-20 pinout, AD9238BSTZ-20 application, or AD9238BSTZ-20 equivalent, key selection criteria include dual-channel crosstalk immunity (>85 dB), clock duty cycle stabilizer (DCS) support, flexible 1–2 V_p-p input range, and LQFP-64 industrial-grade packaging for embedded signal acquisition systems.

Technical Context

The AD9238BSTZ-20 employs a multistage differential pipelined ADC architecture with output error correction logic to guarantee no missing codes across −40°C to +85°C. Its dual sample-and-hold amplifiers (SHAs) enable simultaneous sampling of two independent analog channels with exceptional channel-to-channel isolation.

It features a dedicated duty cycle stabilizer (DCS) circuit that maintains performance over wide clock duty cycle variations, and supports multiplexed data output via MUX_SELECT to reduce interface complexity. Digital outputs are CMOS-compatible, driven by DRVDD (2.25–3.6 V), with pipeline latency fixed at 7 clock cycles.

Key Specifications

Pinout & Package

AD9238BSTZ-20 is housed in a Pb-free, 64-lead LQFP (10 mm × 10 mm, 0.5 mm pitch) with exposed pad connected to AGND. Pinout conforms to Figure 3 in Rev. D datasheet, supporting dual-channel analog input, independent clocking (CLK_A/CLK_B), and separate digital I/O control per channel.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD9238BSTZ-40 and AD9248BSTZ-20, the AD9238BSTZ-20 offers optimal balance of power efficiency (180 mW), industrial temperature rating, and proven crosstalk immunity for cost-sensitive dual-channel acquisition-making it preferred for battery-operated and thermally constrained designs where 12-bit fidelity suffices.

Availability

AD9238BSTZ-20 is available at Aetrix Electronics and suitable for ultrasound equipment, handheld scopemeters, and battery-powered instrumentation requiring stable component supply, long-lifecycle support, and guaranteed industrial-temperature grade performance.

Supply support for AD9238BSTZ-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.

The AD9238 product line delivers dual-channel, low-power, high-isolation ADCs optimized for portable medical imaging, communications infrastructure, and test equipment where channel matching and power efficiency are critical.

FAQ

What is the maximum analog input frequency supported by the AD9238BSTZ-20?

The AD9238BSTZ-20 features a 500 MHz 3 dB analog input bandwidth, enabling undersampling of RF/IF signals up to ~200 MHz while maintaining SNR >68 dB. Performance degrades gradually above Nyquist (10 MHz for 20 MSPS), but usable digitization extends well beyond due to its wideband SHA design and low aperture uncertainty (0.5 ps rms). For best results above 50 MHz, ensure proper layout and impedance matching per the datasheet's analog input section.

Does the AD9238BSTZ-20 require an external voltage reference?

No, the AD9238BSTZ-20 integrates a precision 1.0 V (or 0.5 V) voltage reference with ±35 mV max output error and load regulation of ≤0.8 mV at 1.0 mA. External reference is optional and only needed if tighter initial accuracy (<±5 mV) or temperature drift (<±12 ppm/°C) is required. The SENSE and SHARED_REF pins configure reference mode and routing.

How does the clock duty cycle stabilizer (DCS) function in the AD9238BSTZ-20?

The DCS circuit in the AD9238BSTZ-20 actively corrects clock duty cycle deviations between 30% and 70%, ensuring consistent sampling aperture timing and preserving AC performance (SNR/SFDR) even with asymmetric clocks from PLLs or dividers. When enabled (DCS pin = high), it eliminates need for external duty cycle correction circuits and relaxes clock source design constraints.

Can both channels of the AD9238BSTZ-20 operate independently with different clock sources?

Yes, the AD9238BSTZ-20 accepts asynchronous clocks on CLK_A and CLK_B, allowing fully independent sampling of two analog signals. Each channel has dedicated power-down (PWDN_A/PWDN_B), output enable (OEB_A/OEB_B), and data format control (DFS), enabling flexible use cases like time-interleaved sampling or staggered acquisition without cross-channel synchronization overhead.

What package type and RoHS status does the AD9238BSTZ-20 have?

The AD9238BSTZ-20 is supplied in a Pb-free, 64-lead LQFP (10 mm × 10 mm, 0.5 mm pitch) with exposed thermal pad connected to AGND. It complies with RoHS Directive 2011/65/EU and is rated for the industrial temperature range (−40°C to +85°C). The "Z" suffix in the part number explicitly denotes lead-free LQFP packaging per Analog Devices' ordering guide.