Analog Devices Inc. AD9241AS

Overview

AD9241AS from Analog Devices is a monolithic 14-bit, 1.25 MSPS analog-to-digital converter (ADC) with on-chip sample-and-hold amplifier and programmable voltage reference. It operates on a single +5 V supply, delivers 78.0 dB SNR+D at 100 kHz input, exhibits ±2.5 LSB integral nonlinearity, and uses a 44-pin MQFP package for imaging and communications data acquisition systems.

For engineers reviewing the AD9241AS datasheet, AD9241AS pinout, AD9241AS application, or AD9241AS equivalent, this page provides verified DC/AC specifications, differential input configuration guidance, straight-binary output timing, out-of-range (OTR) flag behavior, and thermal performance data under industrial temperature range (–40°C to +85°C).

Technical Context

The AD9241AS employs a four-stage differential pipelined architecture with digital error correction logic to guarantee no missing codes across its full operating temperature range. It integrates a high-performance switched-capacitor sample-and-hold amplifier optimized for both single-ended and differential inputs, supporting configurable input spans of 2 V or 5 V p-p via internal reference selection (1 V or 2.5 V).

Conversion is clocked by a single edge-triggered input; sampling occurs on the rising edge while the SHA holds during the high phase. The device features three independent power domains (AVDD, DVDD, DRVDD), enabling flexible digital interface compatibility with +3 V or +5 V CMOS logic families through dedicated DRVDD/DRVSS pins.

Key Specifications

Pinout & Package

AD9241AS is housed in a 44-pin Metric Quad Flatpack (MQFP) with 0.8 mm lead pitch and exposed thermal pad. Package thermal resistance is θ_JA = 53.2°C/W, suitable for convection-cooled industrial environments.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 14-bit, ~1 MSPS ADC applications.

Compared with AD9241AS, AD9240ARSZ trades integrated reference and MQFP thermal performance for compact packaging, while ADS8325IPFBT sacrifices speed and analog front-end integration to achieve higher static accuracy-making each suitable only in distinct system-level trade-off contexts.

Availability

AD9241AS is available at Aetrix Electronics and suitable for medical ultrasound imaging, direct-IF communications receivers, and industrial data acquisition systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD9241AS 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, founded in 1965 and headquartered in Wilmington, MA.

The AD9241AS belongs to Analog Devices' high-speed precision ADC product line, engineered for demanding data acquisition applications where resolution, speed, and dc/ac accuracy must coexist within strict power and thermal constraints.

FAQ

What is the maximum recommended clock frequency for continuous operation of the AD9241AS?

The AD9241AS is specified for a minimum clock period of 800 ns, corresponding to a maximum sustained sampling rate of 1.25 MSPS. While the clock period may be extended to 1 ms without performance degradation at +25°C, the device is characterized and guaranteed only up to 1.25 MSPS across its full industrial temperature range. Exceeding this rate risks violating setup/hold timing margins and degrading AC performance metrics such as SFDR and SINAD. Always verify timing compliance using the AD9241AS's tCH/tCL specifications under worst-case voltage and temperature conditions.

Does the AD9241AS support differential input configurations, and how is common-mode level set?

Yes, the AD9241AS natively supports true differential input operation via VINA and VINB pins. Common-mode level is set using the CML pin, which must be biased to AVDD/2 (typically 2.5 V) for optimal THD performance. This is achieved by connecting CML directly to a clean 2.5 V source or via a low-impedance resistive divider. Deviations from midsupply increase RON modulation in the input switches, degrading ac distortion-especially at higher input frequencies. The AD9241AS datasheet confirms that THD improves significantly when CML = 2.5 V versus 1.0 V under identical 2 V input span conditions.

How does the internal voltage reference selection affect the AD9241AS input span and accuracy?

The AD9241AS internal reference is selected via the SENSE pin: grounded for 2.5 V mode (5 V p-p input span), open or pulled high for 1 V mode (2 V p-p input span). In 2.5 V mode, INL is ±2.5 LSB typ and input referred noise is 0.36 LSB rms; in 1 V mode, noise rises to 0.9 LSB rms while INL remains unchanged. Gain error is tighter in 2.5 V mode (0.75% FSR max excluding reference) due to reduced sensitivity to reference drift. Therefore, 2.5 V mode is preferred for high-SNR applications, while 1 V mode suits systems needing lower full-scale voltage swing.

What is the function of the OTR (Out-of-Range) signal on the AD9241AS, and how should it be interpreted?

The OTR signal on the AD9241AS is an active-high, synchronous flag indicating analog input overload-either exceeding +VREF (high overflow) or falling below –VREF (low overflow). It is registered with the same clock as data outputs and aligns with the corresponding conversion result. To distinguish high vs. low overflow, combine OTR with BIT 1 (MSB): MSB = 1 with OTR = 1 indicates high overflow; MSB = 0 with OTR = 1 indicates low overflow. This dual-signal decoding avoids ambiguity during transient saturation events and supports real-time clipping detection in closed-loop systems without post-processing.

Can the AD9241AS operate with separate analog and digital supply voltages, and what are the implications?

No-the AD9241AS requires AVDD = DVDD = DRVDD = +5 V ±5% for specified operation. Although the device separates analog (AVDD/AVSS), digital core (DVDD/DVSS), and output driver (DRVDD/DRVSS) domains, all three supplies must be regulated to the same nominal +5 V level. Using mismatched voltages violates absolute maximum ratings and causes undefined behavior, including latch-up risk and degraded INL/DNL. The separation exists solely to enable independent decoupling and ground isolation-not independent voltage scaling. All supply currents (IAVDD ≈ 10 mA, IDVDD ≈ 2 mA, IDRVDD ≈ 1 mA) are specified only at +5 V.