Analog Devices Inc. AD7942BRMZ-RL7

Overview

AD7942BRMZ-RL7 from Analog Devices is a 14-bit, pseudo-differential successive approximation register (SAR) ADC with 250 kSPS throughput, ±1 LSB INL max, 85 dB SINAD at 20 kHz, and no pipeline delay. It operates from a single 2.3 V to 5.5 V supply, supports 1.8 V–5 V logic via separate VIO, and targets precision data acquisition in space-constrained, low-power systems.

For engineers reviewing the AD7942BRMZ-RL7 datasheet, AD7942BRMZ-RL7 pinout, AD7942BRMZ-RL7 application, or AD7942BRMZ-RL7 equivalent, this page delivers verified specifications, validated pin functions, real-world use contexts for battery-powered instrumentation and medical sensors, and two confirmed alternative parts with documented functional and interface differences.

Technical Context

The AD7942BRMZ-RL7 uses a charge redistribution SAR architecture with on-chip track-and-hold, enabling true single-cycle acquisition and zero-latency conversion results. Its pseudo-differential input accepts 0 V to VREF differential signals referenced to IN−, supporting remote ground sensing and rejecting common-mode noise up to 65 dB at 250 kHz.

The proprietary SPI-compatible serial interface supports both CS mode (with busy indicator) and daisy-chain mode (SDI-driven), synchronized by SCK with timing tolerances as tight as 15 ns at 5 V. Conversion is initiated on the CNV rising edge, and output data appears immediately after tCONV (max 3.2 μs), with no internal pipeline staging.

Key Specifications

Pinout & Package

AD7942BRMZ-RL7 is housed in a 10-lead MSOP package (3.0 mm × 3.0 mm × 1.1 mm), RoHS-compliant, with exposed paddle connected to GND (not required for electrical performance but recommended for thermal stability).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 14-bit SAR ADC applications.

Compared with AD7942BRMZ-RL7, AD7940BRMZ-REEL7 trades speed for lower power at reduced throughput, while AD7685BRMZ-REEL7 retains speed but adds 2 bits of resolution - both preserve mechanical and digital interface compatibility for drop-in evaluation or incremental upgrades.

Availability

AD7942BRMZ-RL7 is available at Aetrix Electronics and suitable for battery-powered equipment, medical instruments, and industrial process controls requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for AD7942BRMZ-RL7 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, serving industrial, automotive, communications, and healthcare markets since 1965.

The AD7942BRMZ-RL7 belongs to Analog Devices' PulSAR® family of precision SAR ADCs, engineered for high-speed, low-power, and zero-latency data acquisition in portable and embedded measurement systems.

FAQ

What is the maximum recommended reference voltage for AD7942BRMZ-RL7?

The AD7942BRMZ-RL7 supports VREF from 0.5 V to VDD, with VDD rated up to 5.5 V. Therefore, the absolute maximum reference voltage is 5.5 V. However, for optimal AC performance (e.g., 85 dB SINAD), Analog Devices specifies VREF = 5 V or 2.5 V in characterization - using VREF > VDD is prohibited, and VREF must remain within the absolute maximum rating of GND −0.3 V to VDD + 0.3 V per the datasheet.

Does AD7942BRMZ-RL7 require an external clock source for conversion?

No, AD7942BRMZ-RL7 does not require an external clock for conversion. It contains an internal conversion clock; the SCK signal is used solely for serial data transfer timing. Conversion is triggered by the CNV rising edge, and the result is available after tCONV (max 3.2 μs), independent of SCK activity - enabling deterministic timing even with variable or paused serial clocks.

Can AD7942BRMZ-RL7 interface directly with a 1.8 V microcontroller?

Yes, AD7942BRMZ-RL7 can interface directly with a 1.8 V microcontroller by setting VIO = 1.8 V. Its digital inputs (CNV, SDI, SCK) accept logic thresholds scaled to VIO (VIH = 0.7 × VIO, VIL = 0.3 × VIO), and SDO outputs are compatible with 1.8 V CMOS levels. No level-shifting circuitry is needed, provided VIO is decoupled and stable.

What is the purpose of the IN− pin on AD7942BRMZ-RL7?

The IN− pin on AD7942BRMZ-RL7 serves as the pseudo-differential analog input reference node - it is not internally connected to GND. By tying IN− to the remote ground of a sensor (e.g., at the tip of a thermocouple or ECG electrode), the ADC rejects common-mode noise and eliminates ground loop errors. The valid input is the voltage difference between IN+ and IN−, ranging from 0 V to VREF.

Is AD7942BRMZ-RL7 pin-compatible with any higher-resolution alternatives?

Yes, AD7942BRMZ-RL7 is pin-for-pin compatible with the 16-bit AD7685BRMZ-REEL7, sharing identical 10-lead MSOP footprint, pin assignments, power sequencing, and serial interface protocol. This allows hardware reuse in designs where resolution upgrade is needed - firmware must accommodate 16-bit data width and updated timing margins, but PCB layout and support components remain unchanged.