Analog Devices Inc. ADA4665-2ARMZ-RL

Overview

ADA4665-2ARMZ-RL from Analog Devices is a dual CMOS rail-to-rail input/output 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-RL datasheet, ADA4665-2ARMZ-RL pinout, ADA4665-2ARMZ-RL application, or ADA4665-2ARMZ-RL equivalent, key selection criteria include its 1 pA max input bias current, ±2.5 V to ±8 V dual-supply compatibility, rail-to-rail output swing down to 4 mV from rails at 10 kΩ load, and operation across −40°C to +125°C.

Technical Context

The ADA4665-2ARMZ-RL employs complementary input stage topology (nMOS/pMOS differential pairs) 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 designs including Sallen-Key low-pass and high-pass topologies up to 10 kHz cutoff.

Designed for single-supply (5 V–16 V) or dual-supply (±2.5 V–±8 V) operation, it maintains 75 dB CMRR and 95 dB PSRR at 25°C while delivering 100 dB open-loop gain and 50° phase margin-enabling robust performance in transimpedance amplifiers and precision reference buffers without external compensation.

Key Specifications

Pinout & Package

ADA4665-2ARMZ-RL is housed in an 8-lead MSOP (RM-8) package with 0.65 mm lead pitch, 3.0 mm × 3.0 mm body, and exposed pad for thermal enhancement. Thermal resistance θJA = 186°C/W (JEDEC 4-layer board).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual rail-to-rail op amp applications.

Compared with AD8667ARZ and ADA4091-2ARMZ, ADA4665-2ARMZ-RL uniquely balances 1.2 MHz bandwidth, 290 μA supply current, and 1 pA input bias-making it optimal for portable medical devices needing both precision and speed without thermal derating.

Availability

ADA4665-2ARMZ-RL is available at Aetrix Electronics and suitable for portable medical sensors, high-side current sensing, precision reference buffering, and multipole active filters requiring stable component supply across extended temperature ranges.

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

The ADA4665-2ARMZ-RL belongs to Analog Devices' precision low-power op amp family, engineered specifically for battery-constrained instrumentation and high-voltage sensor signal chains demanding rail-to-rail operation and nanoscale input bias.

FAQ

What supply voltage range does the ADA4665-2ARMZ-RL support?

The ADA4665-2ARMZ-RL operates from 5 V to 16 V single supply or ±2.5 V to ±8 V dual supply. At 16 V, it draws 290 μA per amplifier typical; at 5 V, supply current drops to 270 μA typical. Absolute maximum supply is 16.5 V, with input voltage range extending from GND −0.3 V to VSY +0.3 V.

How does the rail-to-rail input architecture affect offset voltage in the ADA4665-2ARMZ-RL?

The ADA4665-2ARMZ-RL uses dual nMOS/pMOS input stages, causing a ~1 V transition zone near the positive rail where offset voltage shifts due to differing pair characteristics. This results in 1–6 mV offset at VCM = 0–16 V (16 V supply), with 9 mV max over −40°C to +125°C-documented in Figures 5 and 8 of the datasheet.

Can the ADA4665-2ARMZ-RL drive 10 kΩ loads while maintaining rail-to-rail output swing?

Yes. At 16 V supply and 25°C, ADA4665-2ARMZ-RL delivers VOH = 15.9 V and VOL = 40 mV into 10 kΩ loads-within 100 mV of both rails. Performance degrades slightly at temperature extremes: VOL reaches 150 mV at +125°C, still enabling >98% dynamic range utilization in 12-bit systems.

What is the maximum capacitive load the ADA4665-2ARMZ-RL can drive without instability?

The ADA4665-2ARMZ-RL remains unity-gain stable with up to 100 pF capacitive load when properly decoupled (0.1 μF ceramic at V+ and V–). Figure 29 shows <5% overshoot at 50 pF with RL = 10 kΩ; for >100 pF, external isolation resistor (≥100 Ω) is recommended per Analog Devices Application Note AN-102.

Does the ADA4665-2ARMZ-RL require external compensation for unity-gain configurations?

No. The ADA4665-2ARMZ-RL is internally compensated for unity-gain stability across its full operating range. Electrical Characteristics tables confirm stable 50° phase margin at AV = 1 with RL = 10 kΩ and CL = 50 pF-verified in Figure 21's open-loop gain/phase plots for both 5 V and 16 V supplies.