Analog Devices Inc. AD8672AR

Overview

AD8672AR from Analog Devices is a dual, precision, very low noise, low input bias current operational amplifier in an 8-lead SOIC_N package. It delivers 2.8 nV/√Hz voltage noise, 10 MHz gain bandwidth, ≤75 µV offset voltage, ±5 V to ±15 V dual-supply operation, and unity-gain stability - enabling high-fidelity signal conditioning in GPS receiver filters and precision instrumentation.

For engineers reviewing the AD8672AR datasheet, AD8672AR pinout, AD8672AR application, or AD8672AR equivalent, key selection criteria include verified low-noise performance at 1 kHz, guaranteed −40°C to +125°C operation, channel separation >130 dB at 1 kHz, and confirmed absence of phase reversal under overvoltage conditions.

Technical Context

The AD8672AR implements a bipolar input stage optimized for ultralow voltage noise (2.8 nV/√Hz) and low input bias current (≤12 nA), with rail-to-rail output swing capability into 2 kΩ loads. Its open-loop gain exceeds 120 dB and CMRR reaches 120 dB, supporting high-accuracy closed-loop configurations in sensor front-ends and PLL loop filters.

It features no phase reversal when inputs exceed supply rails by up to 1 V, stable operation with >1000 pF capacitive loads, and thermal design support via documented θJA = 120°C/W for the SOIC_N package - critical for industrial embedded systems requiring long-term reliability at elevated ambient temperatures.

Key Specifications

Pinout & Package

AD8672AR is housed in an 8-lead SOIC_N (R-8) package per JEDEC MS-012-AA, with 1.27 mm lead pitch, 5.00 mm × 4.00 mm body size, and 1.75 mm maximum height.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OP27GS and ADA4004-2, AD8672AR uniquely combines 10 MHz bandwidth, 2.8 nV/√Hz noise, ≤12 nA input bias, and −40°C to +125°C operation - making it the only dual op amp in this group qualified for high-accuracy, wide-temperature industrial signal chains without performance trade-offs.

Availability

AD8672AR is available at Aetrix Electronics and suitable for GPS receiver design, precision instrumentation, professional audio line driving, and industrial sensor signal conditioning requiring stable component supply across extended temperature ranges.

Supply support for AD8672AR 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 AD867x family was designed specifically for precision, low-noise, wide-bandwidth applications in instrumentation, medical devices, and communications infrastructure - emphasizing dc accuracy, noise performance, and robustness over temperature.

FAQ

What is the maximum capacitive load the AD8672AR can drive stably in unity-gain configuration?

The AD8672AR is specified to drive capacitive loads exceeding 1000 pF without instability. Data Sheet Figure 34 shows clean step response with 1 nF load at unity gain, and the General Description explicitly states "Outputs are stable with capacitive loads of over 1000 pF." For heavier loads (>2 nF) or demanding transient response, external compensation (e.g., series resistor + feedback capacitor) is recommended per Figure 35. The AD8672AR's internal compensation ensures unconditional stability in standard configurations without added components.

Does the AD8672AR exhibit phase reversal when input voltages exceed the supply rails?

No, the AD8672AR does not exhibit phase reversal. The General Description and Output Phase Reversal section confirm: "The AD8671/AD8672/AD8674 do not exhibit phase reversal even when the input voltage is 1 V beyond the supplies." This behavior is verified in Figure 31, which shows stable output polarity during overvoltage transients. This eliminates risk of latch-up or erroneous control signals in systems where input transients may exceed rails - a critical advantage over many legacy precision op amps.

What is the guaranteed input offset voltage specification for the AD8672AR over its full operating temperature range?

The AD8672AR guarantees a maximum input offset voltage of 125 µV over the full −40°C to +125°C operating temperature range, as stated in Table 2 (Electrical Characteristics, ±5.0 V) and Table 3 (±15 V). At 25°C, the limit is tighter: 75 µV max. This drift performance (0.3–0.8 µV/°C) ensures predictable error contribution in high-accuracy measurement systems, such as 16-bit data acquisition front-ends where 125 µV corresponds to <2 LSB error at 10 V full scale.

Is the AD8672AR pin-compatible with other op amps in the AD867x family?

Yes, the AD8672AR shares identical 8-lead SOIC_N (R-8) pinout with AD8671ARZ and AD8672ARZ variants, as shown in Figure 2 of the datasheet. All share OUT A, –IN A, +IN A, V–, V+, –IN B, +IN B, OUT B pin assignments. However, AD8671 (single) and AD8674 (quad) use different packages (8-lead and 14-lead respectively) and are not pin-compatible. Board designs using AD8672AR can directly substitute AD8672ARZ or AD8672ARMZ (MSOP) with footprint adaptation, but not AD8671 or AD8674.

What thermal resistance (θ_JA) applies to the AD8672AR in its SOIC_N package?

The AD8672AR in the 8-lead SOIC_N (R-8) package has a junction-to-ambient thermal resistance (θ_JA) of 120°C/W, as documented in Table 5 (Package Characteristics). This value assumes worst-case conditions: device soldered on a 4-layer PCB. With typical supply current of 3.5 mA per amplifier at ±15 V (7 mA total), power dissipation is 105 mW, resulting in a 12.6°C junction-to-ambient rise at 25°C ambient - well within the 150°C absolute maximum junction temperature rating.