The ADA4051-2 is the dual member of Analog Devices' ADA4051 family of CMOS micropower zero-drift amplifiers. Its job is to amplify small, slow, DC-accurate signals - the output of a bridge sensor, a thermocouple, a load cell - without the offset and drift that would otherwise swamp them, and to do it on a power budget small enough for a battery. ADA4051-2ARMZ-R7 is the RoHS-compliant ("Z") 8-lead MSOP version on 7-inch tape and reel.

The defining feature is zero drift. Internally, an auto-zero loop continuously measures and corrects the amplifier's own offset, so the input offset voltage stays near 2 µV and the offset drift is only 20 nV/°C over the full -40°C to +125°C range. For a sensor front end that means the amplifier's error is far below the signal of interest and does not wander with temperature - the property that separates a precision DC amplifier from a general-purpose part. The trade-off of the auto-zero approach is a modest gain bandwidth (115 kHz) and switching activity, which suits the low-frequency, high-accuracy signals this part targets.

What makes the ADA4051-2 distinctive even among zero-drift amplifiers is power: each channel runs on just 13 µA, with rail-to-rail input and output and a 1.8 V to 5.5 V single supply, plus picoamp (10 pA) input bias current. That combination - precision, rail-to-rail and microamp supply - is exactly what a battery-powered scale, a handheld meter or a portable medical instrument needs. The dual amplifier comes in an 8-lead MSOP.

Note: Values are taken from the Analog Devices ADA4051-2 datasheet. Confirm every parameter against the latest official documentation before committing a design.

ADA4051-2ARMZ-R7 is supplied in the 8-lead MSOP (ADI outline RM-8), a compact 3 mm x 3 mm 0.65 mm-pitch surface-mount body. "Z" marks the RoHS-compliant lead-free finish and "R7" the 7-inch tape-and-reel packing. The same ADA4051-2 die is also offered in an 8-lead LFCSP (CP-8); the single ADA4051-1 adds SOT-23-5 and SC-70-5. For a microvolt-offset amplifier, keep input traces short and balanced and guard high-impedance sensor nodes so board leakage does not undo the part's precision. Package dimensions and pin-1 orientation are shown below.

📄 Full specifications are detailed in the official Analog Devices ADA4051-2 datasheet.

The 8-lead MSOP uses the standard dual-amplifier pinout, one amplifier on each side of the package:

• Pin 1 - OUT A: Output, amplifier A.
• Pin 2 - -IN A: Inverting input, amplifier A.
• Pin 3 - +IN A: Non-inverting input, amplifier A.
• Pin 4 - V-: Negative supply (or ground in single-supply use).
• Pin 5 - +IN B: Non-inverting input, amplifier B.
• Pin 6 - -IN B: Inverting input, amplifier B.
• Pin 7 - OUT B: Output, amplifier B.
• Pin 8 - V+: Positive supply (1.8 V to 5.5 V single); decouple close to the pin.

Refer to the package drawing below for the physical pin numbering of the 8-lead MSOP.

The parts below are related ADI zero-drift precision amplifiers, available in our catalog. They are not all drop-in replacements; verify channels, supply, offset and pinout before substituting.

Selection Tips: Stay with the ADA4051-2 when microamp supply current and rail-to-rail operation matter most in a battery sensor front end. Step to AD8629 for a classic auto-zero dual with higher bandwidth, AD8552 for a dual chopper, AD8554 when four channels are needed, or the single AD8628/AD8538 for one channel. All trade some power for bandwidth versus the ADA4051-2.

Analog Devices, Inc. (ADI), headquartered in Wilmington, Massachusetts, USA, is a global leader in high-performance analog, mixed-signal and RF semiconductors, and the reference name in precision amplifiers. The ADA4051-2 belongs to ADI's zero-drift precision amplifier portfolio, where auto-zero offset correction is combined with micropower supply current for battery-operated sensor and instrumentation front ends.

ADI backs the ADA4051-2 with full datasheet characterization, SPICE models and application notes on zero-drift architecture, input guarding and low-offset layout - guidance that matters because at the microvolt level, board leakage and thermocouple junctions can rival the amplifier's own error.