Analog Devices Inc. AD620BNZ

Overview

AD620BNZ from Analog Devices is a low-cost, high-accuracy instrumentation amplifier with gain set by a single external resistor (1–10,000), 50 μV max input offset voltage, 0.6 μV/°C max offset drift, and 1.3 mA max supply current. It operates from ±2.3 V to ±18 V and is widely used in precision ECG front-ends and bridge-based weigh scale signal conditioning.

For engineers reviewing the AD620BNZ datasheet, AD620BNZ pinout, AD620BNZ application, or AD620BNZ equivalent, this page delivers verified specifications, validated pin functions, confirmed medical and industrial use cases, and two rigorously cross-checked alternative parts for design continuity and sourcing flexibility.

Technical Context

The AD620BNZ employs a monolithic three-op-amp architecture with Superβeta bipolar input transistors, enabling 1.0 nA max input bias current and 9 nV/√Hz input voltage noise at 1 kHz. Its laser-trimmed 24.7 kΩ internal resistors ensure accurate gain programming via RG.

It features a reference terminal (REF) for level-shifting output, rail-to-rail-compatible input voltage range (−VS + 1.9 V to +VS − 1.4 V), and 120 kHz small-signal bandwidth at G = 100. Settling time is 15 μs to 0.01% for 10 V steps across G = 1–100.

Key Specifications

Pinout & Package

AD620BNZ is housed in an 8-lead PDIP (Plastic Dual In-line Package) with 0.3-inch body width and through-hole mounting. Pin spacing is 0.1 inch, compatible with standard PCB layouts and socketing for prototyping.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD620BNZ, AD8221ARMZ offers superior dc precision but lacks REF pin flexibility, while AD8226ARMZ achieves 73% lower supply current at the cost of 67% higher voltage noise - making AD620BNZ the balanced choice for medical and industrial applications demanding both accuracy and adaptability.

Availability

AD620BNZ is available at Aetrix Electronics and suitable for ECG front-ends, weigh scale signal chains, and transducer interface circuits requiring stable component supply across industrial, medical, and test equipment lifecycles.

Supply support for AD620BNZ 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.

The AD620 belongs to Analog Devices' precision instrumentation amplifier product line, designed specifically for low-drift, low-noise amplification of weak differential signals from bridges, thermocouples, and biopotential sensors in resource-constrained environments.

FAQ

What is the maximum gain achievable with AD620BNZ?

The AD620BNZ supports a gain range of 1 to 10,000, set by a single external resistor RG connected between Pins 1 and 8. At G = 10,000, RG = 4.94 Ω (1% tolerance recommended). The AD620BNZ maintains 12 kHz bandwidth and 150 μs settling time to 0.01% under this condition, making it suitable for high-gain sensor interfaces where resolution outweighs speed.

Does AD620BNZ support single-supply operation?

Yes, AD620BNZ operates from ±2.3 V to ±18 V, and its input and output stages function correctly with asymmetric or single-ended supplies (e.g., +5 V and GND), provided the REF pin is biased appropriately. For true single-supply use, tie REF to mid-supply (e.g., 2.5 V) and ensure input signals remain within −VS + 1.9 V to +VS − 1.4 V relative to the chosen reference.

What is the purpose of the REF pin on AD620BNZ?

The REF pin on AD620BNZ sets the output DC level relative to the desired system ground or ADC reference. It allows level-shifting without external op amps - for example, tying REF to 2.5 V enables full-scale output swing from 0.1 V to 4.9 V when using a 5 V supply. This feature is essential in single-supply data acquisition systems interfacing with unipolar ADCs.

How does AD620BNZ compare to discrete three-op-amp instrumentation amplifier designs?

AD620BNZ replaces discrete three-op-amp IAs with monolithic integration, delivering 10× lower supply current (1.3 mA vs. 15 mA), 40% smaller PCB footprint, and guaranteed matching of internal resistors. Its laser-trimmed architecture reduces gain error to 0.15% at G = 100 - eliminating manual calibration needed in discrete designs - while maintaining identical functional behavior and pin compatibility in most legacy layouts.

Can AD620BNZ drive an ADC directly?

Yes, AD620BNZ can directly drive SAR and delta-sigma ADCs with input impedances ≥10 kΩ and acquisition times ≥15 μs. Its 15 μs settling time to 0.01% ensures full accuracy for 12-bit to 14-bit conversion at sample rates up to 50 kSPS per channel. For lower-impedance ADCs or faster sampling, add a unity-gain buffer; the AD620BNZ output swing remains within ±VS − 1.4 V at G = 100, aligning with typical ADC input ranges.