Analog Devices Inc. AD7694ARMZRL7

Overview

AD7694ARMZRL7 from Analog Devices is a 16-bit, pseudo-differential, successive approximation register (SAR) analog-to-digital converter (ADC) with 250 kSPS throughput at 5 V, ±4 LSB INL, 92 dB S/(N + D) at 20 kHz, and no pipeline delay. It operates from a single 2.7 V to 5.25 V supply and targets precision data acquisition in battery-powered instrumentation.

For engineers reviewing the AD7694ARMZRL7 datasheet, AD7694ARMZRL7 pinout, AD7694ARMZRL7 application, or AD7694ARMZRL7 equivalent, key selection considerations include its MSOP-8 package, SPI-compatible serial interface, 1 nA standby current, pseudo-differential input architecture (0 V to VREF), and linear power scaling with throughput.

Technical Context

The AD7694ARMZRL7 employs a charge redistribution SAR architecture with integrated track-and-hold, enabling true single-cycle conversion without latency. Its proprietary serial interface supports SPI/QSPI/MICROWIRE/DSP hosts and outputs 16-bit straight-binary data on the falling edge of SCK after CNV goes low.

It features dynamic reference input impedance requiring local 10 µF ceramic decoupling at REF, and its analog input structure uses a 600 Ω series resistance and 30 pF sampling capacitor to form an anti-aliasing filter. Conversion is initiated by a rising edge on CNV, with results available in 3.2 µs (5 V) or 4.66 µs (2.7 V).

Key Specifications

Pinout & Package

AD7694ARMZRL7 is housed in an 8-lead MSOP package (3.0 mm × 3.0 mm, 0.65 mm pitch) with exposed pad not electrically connected. Pin 1 is REF; pins are arranged with analog signals (REF, IN+, IN−, GND) on left side and digital signals (CNV, SDO, SCK, VDD) on right side to support clean layout separation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit SAR ADC applications.

Compared with LTC1864LIMS8#PBF and AD7685BRMZ, AD7694ARMZRL7 offers balanced speed/linearity in the smallest footprint, making it optimal for space-constrained, battery-operated systems where pseudo-differential input suffices and 250 kSPS is required.

Availability

AD7694ARMZRL7 is available at Aetrix Electronics and suitable for portable medical sensors, industrial process monitoring, battery-powered data loggers, and test & measurement equipment requiring stable component supply and long-term production continuity.

Supply support for AD7694ARMZRL7 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 semiconductor company specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The AD7694ARMZRL7 belongs to the PulSAR® family of low-power, high-accuracy SAR ADCs designed for battery-powered instrumentation, portable medical devices, and industrial data acquisition where resolution, speed, and energy efficiency are jointly critical.

FAQ

What is the maximum recommended reference voltage for AD7694ARMZRL7?

The AD7694ARMZRL7 supports an external reference voltage (REF) from 1 V up to VDD. When VDD = 5.25 V, REF may be set as high as 5.25 V. Operation at VREF = VDD is explicitly validated in the datasheet and delivers optimal dynamic performance including 92 dB S/(N + D). Reference voltages below 1 V are not supported and may cause specification violations.

Does AD7694ARMZRL7 require an external clock source for conversion?

No, AD7694ARMZRL7 does not require an external clock for the conversion process. It contains an internal conversion clock. The SCK signal is used solely for serial data readout after conversion completion and has no effect on conversion timing or accuracy. This eliminates timing jitter concerns from host-generated clocks and simplifies system design.

Can AD7694ARMZRL7 interface directly with a 3.3 V microcontroller SPI port?

Yes, AD7694ARMZRL7 can interface directly with a 3.3 V microcontroller SPI port when operated at VDD = 3.3 V. Its digital inputs (CNV, SCK) accept VIH ≥ 1.9 V and VIL ≤ 0.45 V at 2.7 V supply, well within 3.3 V logic thresholds. SDO output VOH ≥ VDD − 0.3 V ensures compatible high-level signaling, and VOL ≤ 0.4 V meets standard CMOS low-level requirements.

What is the purpose of the IN− pin on AD7694ARMZRL7?

The IN− pin on AD7694ARMZRL7 serves as the analog ground sense reference for the pseudo-differential input pair (IN+, IN−). It is not a true differential input but enables rejection of common-mode noise by referencing IN+ to a remote ground point-such as a sensor's local ground-thereby eliminating ground potential differences between sensor and ADC. IN− must be connected to a clean analog ground plane or remote sense point, not left floating.

How does power consumption scale with sampling rate in AD7694ARMZRL7?

AD7694ARMZRL7 power consumption scales linearly with throughput due to automatic power-down between conversions. At 100 kSPS and 5 V, it draws 0.8–1.2 mA; at 100 SPS, current drops to ~4 µA (≈4 µW). This behavior is confirmed in Figure 22 of the datasheet and makes AD7694ARMZRL7 especially efficient in burst-mode or event-triggered acquisition systems where average sampling rate is low.