Analog Devices Inc. AD8278ARMZ

Overview

AD8278ARMZ from Analog Devices is a precision, low-power difference amplifier with fixed gain options of G = ½ or G = 2, designed for high-accuracy signal conditioning in power-constrained systems. It delivers 80 dB minimum CMRR (dc to 20 kHz), 1 MHz bandwidth at G = ½, and operates from single supplies as low as 2.0 V up to 36 V - enabling use in battery-powered voltage/current monitoring and industrial sensor interfaces.

For engineers reviewing the AD8278ARMZ datasheet, AD8278ARMZ pinout, AD8278ARMZ application, or AD8278ARMZ equivalent, key selection criteria include its rail-to-rail input common-mode range beyond supplies (up to ±3×VS), 200 μA max supply current, laser-trimmed internal resistor network for <0.02% gain error, and rugged input overvoltage protection - all in an 8-lead MSOP package.

Technical Context

The AD8278ARMZ integrates matched thin-film resistors and a precision op amp in a monolithic architecture optimized for differential-to-single-ended conversion. Its input stage supports common-mode voltages extending to −3(VS + 0.1) V and +3(VS − 1.5) V at G = ½, enabling direct measurement of high-side signals without level-shifting circuitry.

It features enhanced slew rate (1.4 V/μs), low offset drift (±1 μV/°C max, Grade B), and gain drift (1 ppm/°C max), making it suitable for stable dc-coupled instrumentation where thermal stability is critical. The SENSE terminal enables Kelvin sensing for improved accuracy in current-sense applications.

Key Specifications

Pinout & Package

The AD8278ARMZ is housed in an 8-lead MSOP package (3 mm × 3 mm, 0.87 mm height) with exposed pad for thermal performance. Pin 8 is NC (no connect); all other pins are electrically active and functionally defined per Analog Devices Rev. C datasheet.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar difference amplifier applications.

Compared with AD8276ARMZ and INA199A1DCKR, the AD8278ARMZ uniquely combines dual-gain flexibility (G = ½/2), extended input common-mode range beyond supplies, and Kelvin sensing - making it optimal for precision voltage monitoring and bidirectional current measurement where design adaptability matters.

Availability

AD8278ARMZ is available at Aetrix Electronics and suitable for voltage measurement and monitoring, current measurement and monitoring, and portable, battery-powered equipment requiring stable component supply and long-term industrial-grade availability.

Supply support for AD8278ARMZ 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.

The AD8278ARMZ belongs to Analog Devices' precision difference amplifier product line, engineered for low-power, high-CMRR signal conditioning in industrial, automotive, and portable instrumentation where accuracy, robustness, and supply flexibility are essential.

FAQ

What is the maximum supply voltage for the AD8278ARMZ?

The AD8278ARMZ supports a maximum supply voltage of ±18 V for dual supplies or 36 V for single supplies, as specified in its Absolute Maximum Ratings table. Operation beyond these limits risks permanent damage. At ±15 V, it delivers full performance including 1 MHz bandwidth and 80 dB CMRR; derating applies above ±15 V due to increased power dissipation and thermal constraints. Always verify junction temperature using θJA = 135°C/W (MSOP) under actual load conditions.

Can the AD8278ARMZ be used with a single 3.3 V supply?

Yes, the AD8278ARMZ operates from a single 2.0 V to 36 V supply, including 3.3 V. At 3.3 V, it maintains G = ½ or G = 2 functionality with 870 kHz bandwidth (G = ½), 80 dB CMRR, and input common-mode range from −10.2 V to +1.95 V. The REF pin should be tied to 1.65 V (midsupply) for optimal dynamic range, and output swing is specified as −VS + 0.1 V to +VS − 0.15 V, yielding ~0.1 V to 3.15 V with proper loading.

What is the purpose of the SENSE pin on the AD8278ARMZ?

The SENSE pin on the AD8278ARMZ enables Kelvin (4-wire) sensing to eliminate voltage drop errors caused by PCB trace or shunt resistor lead resistance. When used in current-sense configurations, SENSE connects directly to the shunt's low-side terminal, while −IN and +IN connect to the shunt's high- and low-side measurement points. This forces the amplifier to regulate its output based on the true voltage across the shunt, improving accuracy to within 0.1% even with 100 mΩ trace resistance - critical for precision bidirectional current measurement.

Does the AD8278ARMZ require external resistors for gain setting?

No, the AD8278ARMZ does not require external resistors for gain setting. It integrates laser-trimmed thin-film resistors that fix the gain at either G = ½ or G = 2 depending on the external connection of the SENSE and REF pins. This eliminates gain-setting errors from external component tolerances, reduces board area, improves temperature stability (1 ppm/°C gain drift), and simplifies layout - distinguishing it from discrete op-amp + resistor solutions that typically achieve only 0.1% gain accuracy and 25 ppm/°C drift.

How does the AD8278ARMZ handle input overvoltage conditions?

The AD8278ARMZ incorporates rugged input overvoltage protection that allows each input to withstand voltages from −VS + 40 V to +VS − 40 V without damage or latch-up. This is achieved through internal ESD structures and series current-limiting elements. In practice, this means the device can survive accidental connection to 48 V lines in a 24 V system or transient spikes up to ±40 V relative to supply rails - eliminating the need for external protection diodes in many industrial applications and reducing BOM count and failure modes.