Analog Devices Inc. ADA4665-2ARMZ

Overview

ADA4665-2ARMZ from Analog Devices is a dual, rail-to-rail input/output CMOS operational amplifier optimized for low-power, high-voltage precision applications. It delivers 1.2 MHz gain bandwidth, 1 V/μs slew rate, and 290 μA per amplifier supply current at 16 V, enabling use in portable medical sensors and high-density power budget systems.

For engineers reviewing the ADA4665-2ARMZ datasheet, ADA4665-2ARMZ pinout, ADA4665-2ARMZ application, or ADA4665-2ARMZ equivalent, key selection criteria include its 1 pA max input bias current, −40°C to +125°C operating range, rail-to-rail swing at 5 V–16 V single-supply, and MSOP-8 packaging for space-constrained designs.

Technical Context

The ADA4665-2ARMZ employs dual complementary MOS input stages (nMOS and pMOS) to achieve true rail-to-rail input operation, with transition near 1 V below V₊ causing measurable offset voltage shift. Its unity-gain stable architecture supports active filter and transimpedance configurations without external compensation.

Designed for wide supply flexibility, it operates from ±2.5 V to ±8 V dual supply or 5 V to 16 V single supply, maintaining 3 μV/°C typical offset drift and 75 dB CMRR over 0–100 kHz - critical for physiological measurement front ends and precision reference buffering where common-mode rejection and thermal stability are non-negotiable.

Key Specifications

Pinout & Package

ADA4665-2ARMZ is housed in an 8-lead MSOP (RM-8) package, 3.0 mm × 3.0 mm × 0.85 mm body, with exposed pad for thermal enhancement. Pin 1 marked via laser indentation; JEDEC MO-187-AA compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual precision op amp applications.

Compared with AD8667ARMZ and ADA4091-2ARMZ, ADA4665-2ARMZ uniquely balances ultra-low bias current, rail-to-rail input capability across full supply range, and sub-300 μA quiescent current - making it optimal for battery-powered precision analog front ends where both input range and power efficiency are simultaneously critical.

Availability

ADA4665-2ARMZ is available at Aetrix Electronics and suitable for portable medical sensors, high-voltage industrial monitoring, and current shunt sensing requiring stable component supply across extended temperature and voltage ranges.

Supply support for ADA4665-2ARMZ 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, serving industrial, communications, automotive, and healthcare markets since 1965.

The ADA4665-2ARMZ belongs to Analog Devices' precision rail-to-rail op amp product line, engineered specifically for low-power, high-voltage applications demanding nanoscale input bias current and guaranteed operation from −40°C to +125°C.

FAQ

What is the maximum supply voltage for ADA4665-2ARMZ?

The ADA4665-2ARMZ has an absolute maximum supply voltage rating of 16.5 V. Its specified operating range is 5 V to 16 V single supply or ±2.5 V to ±8 V dual supply. Operation beyond 16 V risks permanent damage per Absolute Maximum Ratings Table 5. The ADA4665-2ARMZ achieves optimal performance - including full rail-to-rail output swing and 1.2 MHz bandwidth - within this 5–16 V window.

Does ADA4665-2ARMZ support true rail-to-rail input at 5 V supply?

Yes, ADA4665-2ARMZ supports true rail-to-rail input at 5 V supply, with common-mode voltage range specified from 0 V to 5 V over temperature. Its dual-input-stage architecture (nMOS and pMOS) enables continuous operation across the entire supply range, though a small offset voltage shift occurs near V₊ −1 V due to input pair crossover - documented in Figures 5 and 8 of the datasheet. This behavior is inherent to rail-to-rail input design and does not impair functionality in 5 V systems.

What is the thermal resistance (θ_JA) of ADA4665-2ARMZ in MSOP-8 package?

The ADA4665-2ARMZ in MSOP-8 (RM-8) package has a junction-to-ambient thermal resistance (θ_JA) of 186°C/W, measured on a 4-layer JEDEC standard PCB. This value assumes worst-case board layout; actual θ_JA improves with copper pour and thermal vias under the exposed pad. The junction-to-case (θ_JC) is 52°C/W, enabling accurate junction temperature estimation using case temperature measurements during thermal validation.

Can ADA4665-2ARMZ drive 10 kΩ loads at 16 V supply while maintaining rail-to-rail output?

Yes, ADA4665-2ARMZ drives 10 kΩ loads at 16 V supply with VOH ≥15.9 V and VOL ≤75 mV - achieving rail-to-rail output swing within 100 mV of both rails. Per Table 3, VOH = 15.9 V min and VOL = 75 mV max at RL = 10 kΩ, confirming full-scale signal delivery to downstream 16-bit ADCs or comparators. Performance remains stable across −40°C to +125°C, with VOH degrading only to 15.8 V and VOL rising to 150 mV at temperature extremes.

Is ADA4665-2ARMZ suitable for transimpedance amplifier (TIA) circuits with photodiodes?

Yes, ADA4665-2ARMZ is well-suited for TIA circuits with photodiodes due to its 1 pA maximum input bias current, 7 pF common-mode input capacitance, and 1.2 MHz bandwidth - all critical for minimizing dark current error and ensuring stability with typical 1–10 pF diode junction capacitance. Its rail-to-rail output allows full utilization of the feedback resistor's dynamic range, and its 32 nV/√Hz voltage noise at 1 kHz supports low-noise optical detection in portable analyzers.