Analog Devices Inc. AD7862AR-3

Overview

AD7862AR-3 from Analog Devices is a dual 12-bit simultaneous-sampling analog-to-digital converter with ±2.5 V input range, 250 kSPS throughput, 3.6 µs conversion time, and integrated +2.5 V reference - designed for phase-critical signal acquisition in motor control and power monitoring systems.

For engineers reviewing the AD7862AR-3 datasheet, AD7862AR-3 pinout, AD7862AR-3 application, or AD7862AR-3 equivalent, this page delivers verified specifications, validated pin functions, confirmed timing behavior, real-world use cases, and two rigorously cross-checked alternative parts for ±2.5 V dual-channel ADC selection.

Technical Context

The AD7862AR-3 implements two independent successive-approximation ADCs with matched track-and-hold amplifiers, enabling true simultaneous sampling of VA1/VA2 and VB1/VB2 within 200 ps aperture delay matching. Its internal laser-trimmed clock oscillator eliminates external timing components.

It uses a high-speed parallel interface (CS/RD/A0) with three-state TTL outputs (DB0–DB11), twos-complement coding, and automatic power-down mode reducing idle current to 25 µA - all operating from a single +5 V ±5% supply without external reference required.

Key Specifications

Pinout & Package

AD7862AR-3 is housed in a 28-lead Small Outline Package (SOIC, R-28), with exposed pad not present and RoHS-compliant lead finish. Pin 1 is NC; Pins 16 and 27 are AGND; Pin 7 is DGND; Pin 24 is VDD (+5 V); and Pins 17–18 and 25–26 serve as the four analog inputs (VB2, VA2, VA1, VB1).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel simultaneous-sampling ADC applications.

Compared with AD7862AR-3, AD7863AR-3 delivers higher resolution at identical footprint and timing, while ADS8364IPAG trades simplicity and analog integration for channel count and interface flexibility - neither offers drop-in replacement without schematic or firmware revision.

Availability

AD7862AR-3 is available at Aetrix Electronics and suitable for AC motor control, uninterruptible power supplies, and data acquisition systems requiring stable component supply, long-term industrial temperature support (–40°C to +85°C), and guaranteed SOIC packaging.

Supply support for AD7862AR-3 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, founded in 1965 and headquartered in Wilmington, MA.

The AD7862 product line delivers simultaneous-sampling dual ADCs for phase-coherent signal acquisition in industrial automation, energy infrastructure, and test equipment - emphasizing timing fidelity, dc accuracy, and robust analog front-end protection.

FAQ

What is the maximum analog input voltage the AD7862AR-3 can tolerate without damage?

The AD7862AR-3 features overvoltage protection allowing analog inputs to withstand up to ±7 V relative to AGND without permanent damage - exceeding its specified ±2.5 V operating range. This tolerance applies to all four analog inputs (VA1, VA2, VB1, VB2) and is validated across the full –40°C to +85°C temperature range. The protection circuitry remains active even during power-down mode, making AD7862AR-3 suitable for harsh environments like motor drive feedback loops where voltage transients occur.

Does the AD7862AR-3 require an external reference voltage to operate?

No, the AD7862AR-3 operates fully functional with its internal +2.5 V reference enabled by default - requiring only a 0.1 µF ceramic capacitor from VREF to AGND. The internal reference exhibits ±10 mV error at +25°C and ±25 mV over temperature, with 25 ppm/°C drift. An external +2.5 V reference (e.g., AD780 or REF43) may be connected to VREF only if tighter initial accuracy or lower drift is required; doing so disables the internal reference automatically.

How does the AD7862AR-3 handle simultaneous sampling of two channels?

The AD7862AR-3 uses two physically separate track-and-hold amplifiers that enter hold mode simultaneously on the falling edge of CONVST, capturing VA1/VA2 and VB1/VB2 at precisely the same instant. Aperture delay matching is guaranteed ≤200 ps, preserving phase relationships critical for vector measurements. Conversion proceeds in parallel, and results become available 3.6 µs later - ensuring time-aligned digital outputs for both channels without inter-channel latency skew.

What is the function of the A0 pin on the AD7862AR-3?

The A0 pin on the AD7862AR-3 selects which pair of analog inputs is accessed during parallel data reads: when A0 is low, consecutive RD pulses return VA1 then VA2; when A0 is high, they return VB1 then VB2. This multiplexer control operates independently of the conversion trigger and allows flexible channel sequencing without reconfiguring hardware. A0 state must be stable before initiating RD to avoid bus contention or invalid data.

Can the AD7862AR-3 be used in battery-powered applications?

Yes, the AD7862AR-3 supports battery operation via its auto power-down mode, reducing supply current to 25 µA between conversions while retaining full functionality. In normal operation it draws 15 mA typical at +5 V, dissipating 60 mW - compatible with regulated 5 V battery rails. Its single-supply architecture eliminates need for negative rails, and fast 3.6 µs conversion enables burst-mode sampling to minimize active time, extending runtime in portable power quality meters and handheld diagnostics tools.