Analog Devices Inc. AD7894BRZ-10REEL7

Overview

AD7894BRZ-10REEL7 from Analog Devices is a 14-bit, 5 µs successive-approximation analog-to-digital converter (ADC) with integrated track/hold amplifier, on-chip clock, and high-speed two-wire serial interface. It operates from a single +5 V supply, accepts ±10 V analog input range, delivers 77 dB SNR at 70 kHz input, and consumes 20 mW typical power-designed for precision data acquisition in industrial instrumentation and automated test equipment.

For engineers reviewing the AD7894BRZ-10REEL7 datasheet, AD7894BRZ-10REEL7 pinout, AD7894BRZ-10REEL7 application, or AD7894BRZ-10REEL7 equivalent, key selection considerations include its ±10 V bipolar input range, twos-complement output coding, 5 µs conversion time in high-sampling mode, SO-8 package compatibility, and support for 160 kHz throughput with proper timing coordination between CONVST, BUSY, and SCLK.

Technical Context

The AD7894BRZ-10REEL7 implements a laser-trimmed internal clock driving a 14-bit R-2R ladder SAR core, with on-chip signal scaling enabling ±10 V full-scale input while powered from +5 V only. Its track/hold amplifier achieves 0.35 µs acquisition time and >7.5 MHz small-signal bandwidth, supporting accurate digitization of fast-changing signals up to Nyquist frequency.

It supports two operating modes: Mode 1 (high sampling) initiates conversion on falling CONVST edge with 5 µs conversion time; Mode 2 enables automatic power-down after conversion, requiring wake-up before next CONVST-reducing IDD to 20 µA max in standby. Serial data is output as 16-bit frame (two leading zeros + 14-bit twos-complement result) synchronized to falling SCLK edges.

Key Specifications

Pinout & Package

AD7894BRZ-10REEL7 is housed in an 8-lead narrow-body SOIC (SO-8) package with standard JEDEC MS-012AC footprint (5.3 mm × 4.4 mm, 1.27 mm pitch). Pin 1 is marked by beveled corner or dot; device is lead-free and RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7894ARZ-10, the AD7894BRZ-10REEL7 offers tighter linearity for demanding calibration tasks; compared with ADS8860IDRCT, it trades resolution for integration-eliminating external reference and track/hold components while delivering sufficient accuracy for industrial control loops.

Availability

AD7894BRZ-10REEL7 is available at Aetrix Electronics and suitable for industrial process monitoring, automated test equipment, and portable data loggers requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for AD7894BRZ-10REEL7 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 AD7894 product line delivers integrated, single-supply SAR ADCs optimized for space-constrained, low-power industrial data acquisition systems-emphasizing ease of use, timing simplicity, and robust analog front-end performance.

FAQ

What is the maximum recommended SCLK frequency for reliable operation of the AD7894BRZ-10REEL7?

The AD7894BRZ-10REEL7 supports up to 16 MHz SCLK, but system-level timing must respect t₄ (60 ns max data access time) and t₅ (10 ns min data hold time) to avoid read errors. At 16 MHz, the 16-bit serial read completes in 1.0 µs, enabling 160 kHz throughput only when combined with 5 µs conversion time and 250 ns quiet period. Lower frequencies simplify timing margining in noise-prone environments.

Does the AD7894BRZ-10REEL7 require an external reference, and what are the consequences of reference inaccuracy?

Yes, the AD7894BRZ-10REEL7 requires an external +2.5 V ±5% reference applied to the REF IN pin. Reference inaccuracy directly contributes to gain error-e.g., a 0.1% error in REF IN causes ~0.1% full-scale error in the AD7894BRZ-10REEL7 output. Precision references like the AD780 or ADR4525 are recommended to maintain specified ±1.5 LSB INL performance across temperature.

How does the auto power-down mode function in the AD7894BRZ-10REEL7, and when should it be used?

In auto power-down mode (Mode 2), the AD7894BRZ-10REEL7 enters standby after BUSY goes low, reducing IDD to 20 µA max. It wakes up upon rising CONVST edge, with ~5 µs wake-up time before conversion begins. This mode is ideal for low-duty-cycle applications like periodic sensor polling, where average power must be minimized without sacrificing per-sample accuracy or timing determinism.

What is the significance of the "B" grade in AD7894BRZ-10REEL7, and how does it differ from "A" grade variants?

The "B" grade in AD7894BRZ-10REEL7 specifies ±1.5 LSB integral nonlinearity (INL) over –40°C to +85°C, versus ±2 LSB for "A" grade (e.g., AD7894ARZ-10). Both grades share identical pinout, timing, power, and package. The B grade is selected for applications demanding tighter DC accuracy-such as calibrated instrumentation-where the 0.5 LSB improvement validates its typically higher unit cost.

Can the AD7894BRZ-10REEL7 interface directly with common microcontrollers, and what logic level compatibility should be observed?

Yes, the AD7894BRZ-10REEL7 interfaces directly with 5 V-tolerant microcontrollers. Its digital inputs (CONVST, SCLK) accept VIH ≥2.4 V and VIL ≤0.8 V at VDD = 5 V ±5%, matching standard TTL/CMOS thresholds. SDATA output drives VOH ≥4.0 V (at 400 µA) and VOL ≤0.4 V (at 1.6 mA), ensuring robust noise margins. No level-shifting is needed for 5 V MCU hosts.