Analog Devices Inc. AD7856ARSZ-REEL7

Overview

AD7856ARSZ-REEL7 from Analog Devices is a 14-bit, 285 kSPS successive approximation register (SAR) analog-to-digital converter (ADC) operating from a single 5 V supply. It features eight single-ended or four pseudo-differential analog inputs, on-chip 4.096 V reference, self- and system calibration, and SPI/QSPI/μP-compatible serial interface. It targets high-accuracy data acquisition in battery-powered instrumentation and control systems.

For engineers reviewing the AD7856ARSZ-REEL7 datasheet, AD7856ARSZ-REEL7 pinout, AD7856ARSZ-REEL7 application, or AD7856ARSZ-REEL7 equivalent, key selection criteria include throughput rate (285 kSPS), integral nonlinearity (±2 LSB max), power-down modes (2.5 mW typ), track-and-hold acquisition time (500 ns), and support for flexible reference voltages (1.2 V to VDD).

Technical Context

The AD7856ARSZ-REEL7 implements a charge redistribution SAR architecture with integrated track-and-hold, internal DAC, and calibration memory. Its conversion sequence is triggered by CONVST or software command via the control register, and completion is signaled by BUSY.

It supports two serial interface modes: Mode 2 (3-wire, DIN as input only) and Mode 1 (2-wire, DIN bidirectional). Calibration is initiated via CAL pin or control register bits (CALMD, CALSLT1/0, STCAL), with full self-calibration requiring ~41.7 ms at 6 MHz CLKIN.

Key Specifications

Pinout & Package

AD7856ARSZ-REEL7 is housed in a 24-lead SSOP (Shrink Small Outline Package) with 0.15 mm lead pitch and body size 7.6 × 4.4 mm. The package is RoHS-compliant and designed for surface-mount reflow assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7856ARSZ-REEL7, AD7980BRMZ-REEL offers higher resolution and speed at the cost of increased system complexity, while ADS8325IPW trades throughput and calibration capability for lower power and simpler integration in 3 V domains.

Availability

AD7856ARSZ-REEL7 is available at Aetrix Electronics and suitable for battery-powered instrumentation, industrial process monitoring, medical vital sign acquisition, communications baseband digitization, and high-accuracy sensor interface applications requiring stable component supply across extended temperature ranges.

Supply support for AD7856ARSZ-REEL7 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, with design and manufacturing operations worldwide.

The AD7856ARSZ-REEL7 belongs to Analog Devices' precision SAR ADC product line, engineered for high-speed, low-power, and high-accuracy data acquisition in demanding industrial, medical, and instrumentation environments.

FAQ

What is the maximum sample rate of the AD7856ARSZ-REEL7?

The AD7856ARSZ-REEL7 achieves a maximum throughput rate of 285 kSPS under A-grade conditions (–40°C to +105°C) with a 6 MHz master clock. This corresponds to a conversion time of 3.5 µs. At the K-grade specification (0°C to +105°C), the maximum rate drops to 102 kSPS using a 4 MHz clock. The part maintains full 14-bit performance across this range.

Does the AD7856ARSZ-REEL7 require an external reference voltage?

No-the AD7856ARSZ-REEL7 includes an internal 4.096 V reference accessible at the REFIN/REFOUT pin, enabling fully self-contained operation. However, it also supports external references from 1.2 V to VDD, allowing users to optimize full-scale range, noise, or temperature drift for specific applications.

How does the AD7856ARSZ-REEL7 handle power management in portable systems?

The AD7856ARSZ-REEL7 supports multiple low-power states: automatic power-down after conversion (2.5 mW typ), SLEEP pin–controlled full shutdown (5 µA typ with clock off), and partial power-down (400 µA typ). These modes preserve calibration data and allow rapid wake-up, making AD7856ARSZ-REEL7 ideal for duty-cycled battery-powered devices.

Can the AD7856ARSZ-REEL7 interface directly with an 8051 microcontroller?

Yes-the AD7856ARSZ-REEL7's serial interface is explicitly compatible with 8051-family controllers. It supports Mode 2 (standard 3-wire SPI) and Mode 1 (2-wire with bidirectional DIN), both configurable via the control register. Timing parameters (e.g., t7 = 30 ns setup, t8 = 20 ns hold) meet 8051 bus requirements at standard clock speeds.

What calibration capabilities does the AD7856ARSZ-REEL7 provide?

The AD7856ARSZ-REEL7 provides both self-calibration (on-chip DAC and offset/gain adjustment) and system calibration (user-applied reference for end-to-end error correction). Calibration is triggered via the CAL pin or control register bits (STCAL, CALMD), with full self-calibration taking ~41.7 ms at 6 MHz. Offset and gain calibration spans are ±0.0375×VREF and ±0.01875×VREF respectively.