Analog Devices Inc. AD7858AR-REEL

Overview

AD7858AR-REEL from Analog Devices is a 12-bit, 200 kSPS SAR analog-to-digital converter with eight single-ended or four pseudo-differential inputs, 2.5 V internal reference, and SPI/QSPI/8051-compatible serial interface - designed for battery-powered instrumentation requiring high accuracy, low power, and fast acquisition (500 ns track/hold). It operates from a single 3 V to 5.5 V supply and integrates self-calibration and system calibration.

For engineers reviewing the AD7858AR-REEL datasheet, AD7858AR-REEL pinout, AD7858AR-REEL application, or AD7858AR-REEL equivalent, this page delivers verified technical context on its 24-lead SOIC package, 12-bit resolution with ±1 LSB INL, 70 dB SNR at 10 kHz, flexible power-down modes (25 µW sleep), and channel configuration via control register - all critical for portable medical devices, PDA data acquisition, and industrial sensor interfaces.

Technical Context

The AD7858AR-REEL employs a charge redistribution DAC architecture with integrated track-and-hold, enabling 500 ns acquisition time and full 12-bit settling. Its on-chip 2.5 V reference supports input ranges from 0 V to VREF, and it accepts external references from 1.2 V to AVDD.

Calibration is implemented via dedicated CAL pin and internal registers: self-calibration (7 ms typical at 4 MHz CLKIN), system offset (3.47 ms), and full-scale (27.78 ms). Serial communication uses frame-synced SCLK with three interface modes, supporting read/write during or after conversion to sustain 200 kSPS throughput.

Key Specifications

Pinout & Package

AD7858AR-REEL is housed in a 24-lead SOIC (R-24) package with standard 0.3-inch width and 1.27 mm pitch. Pin functions are electrically validated per Analog Devices Rev. B datasheet.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with AD7858BR-REEL, the AD7858AR-REEL trades minor INL degradation (±1 LSB) for broader A-grade availability and lower cost; versus AD7858LAR-REEL, it doubles throughput at 3× higher power - making AD7858AR-REEL optimal for speed-constrained portable instrumentation where moderate power is acceptable.

Availability

AD7858AR-REEL is available at Aetrix Electronics and suitable for battery-powered medical instruments, industrial sensor data loggers, and portable test equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for AD7858AR-REEL 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, headquartered in Norwood, MA, with R&D and manufacturing operations worldwide.

The AD7858AR-REEL belongs to Analog Devices' precision SAR ADC product line, engineered for portable and embedded systems demanding high DC accuracy, low power, and robust serial interfacing without external reference components.

FAQ

What is the maximum sampling rate supported by the AD7858AR-REEL?

The AD7858AR-REEL supports a maximum throughput rate of 200 kSPS, achieved with a 4 MHz master clock (CLKIN). This allows full 12-bit conversion every 4.6 µs and sustains continuous sampling at Nyquist frequencies up to 100 kHz - confirmed in the Rev. B datasheet timing specifications under "CONVERSION RATE" and "TIMING SPECIFICATIONS" sections.

Does the AD7858AR-REEL require an external reference voltage?

No, the AD7858AR-REEL includes an internal 2.5 V reference accessible via the REFIN/REFOUT pin, eliminating the need for an external reference in most applications. However, it also supports external references from 1.2 V to AVDD, providing flexibility for systems requiring tighter reference stability or different input ranges - as specified in the "REFERENCE INPUT/OUTPUT" table and "GENERAL DESCRIPTION."

How does the AD7858AR-REEL handle channel selection for its eight analog inputs?

The AD7858AR-REEL configures its eight analog inputs (AIN1–AIN8) as either eight single-ended channels or four pseudo-differential pairs via the SGL/DIFF bit and CH2–CH0 bits in the write-only Control Register. This software-selectable routing is detailed in Table III and the "ON-CHIP REGISTERS" section, enabling dynamic reconfiguration without hardware changes.

What power-down modes are available on the AD7858AR-REEL, and how are they controlled?

The AD7858AR-REEL offers full and partial power-down modes controlled by PMGT1/PMGT0 bits in the Control Register, plus a hardware SLEEP pin. Full power-down draws 5 µA (external clock off), while partial mode consumes 400 µA - both retain calibration data. These modes are documented in the "POWER DISSIPATION" table and "Power-Down" subsection of the Rev. B datasheet.

Is the AD7858AR-REEL pin-compatible with other members of the AD7858 family?

Yes, the AD7858AR-REEL shares identical 24-lead SOIC (R-24) pinout and electrical interface with AD7858BN, AD7858LAR, and AD7858LBR variants. All share the same CONVST/BUSY/SLEEP/REFIN/REFOUT/DIN/DOUT/SCLK/SYNC/CLKIN/AVDD/AGND/DVDD/DGND/CREF1/CREF2/AIN1–AIN8/CAL pin mapping - verified in the "PIN CONFIGURATIONS" and "PIN FUNCTION DESCRIPTIONS" sections of the datasheet.