Analog Devices Inc. AD8671ARMZ

Overview

AD8671ARMZ from Analog Devices is a precision, very low noise, low input bias current operational amplifier in an 8-lead MSOP package. It delivers 2.8 nV/√Hz voltage noise density, 10 MHz gain bandwidth, 75 µV max offset voltage, and operates from ±5 V to ±15 V supplies across –40°C to +125°C. It is used in high-stability PLL filters, GPS receiver front-end signal conditioning, and professional audio preamplification.

For engineers reviewing the AD8671ARMZ datasheet, AD8671ARMZ pinout, AD8671ARMZ application, or AD8671ARMZ equivalent, key selection criteria include verified ultralow noise performance at 1 kHz, guaranteed input bias current ≤12 nA over temperature, unity-gain stability with >1000 pF capacitive load drive, and MSOP package thermal resistance (θ_JA = 142°C/W) for thermal-aware layout planning.

Technical Context

The AD8671ARMZ employs a precision bipolar input stage optimized for ultralow voltage noise and minimal drift, achieving 0.5 µV/°C max offset drift over –40°C to +125°C. Its open-loop gain exceeds 120 dB and remains stable under unity-gain configuration with no phase reversal - even when inputs exceed supply rails by 1 V.

It supports dual-supply operation from ±5 V to ±15 V, delivers ±10 mA output current into 2 kΩ loads, and maintains 77 nV p-p (0.1 Hz to 10 Hz) integrated noise. The 8-lead MSOP package enables compact placement while requiring attention to PCB thermal relief due to θ_JA = 142°C/W.

Key Specifications

Pinout & Package

AD8671ARMZ is housed in an 8-lead MSOP (RM-8) package per JEDEC MO-187-AA, with 0.65 mm pitch, 3.0 mm × 3.0 mm body, and exposed pad for thermal enhancement (not electrically connected). Pin 1 identifier located at top-left corner with 15° max bevel.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD8671ARMZ, AD8675ARZ trades extended temperature rating for identical noise and bandwidth in SOIC-8, while ADA4004-1ARMZ offers superior noise at the cost of bandwidth and power efficiency - making AD8671ARMZ optimal for wideband, high-temp, low-noise precision applications.

Availability

AD8671ARMZ is available at Aetrix Electronics and suitable for PLL loop filter design, GPS receiver signal chains, and medical instrumentation requiring stable component supply with full traceability and extended temperature qualification.

Supply support for AD8671ARMZ 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 demanding both dc accuracy and dynamic performance - including instrumentation, communications infrastructure, and high-end audio.

FAQ

What is the maximum capacitive load the AD8671ARMZ can drive without external compensation?

The AD8671ARMZ is specified to drive capacitive loads exceeding 1000 pF while maintaining stability in unity-gain configuration. Test data shows clean step response with 1 nF loads; however, for loads >1 nF or in low closed-loop gain configurations, external RC compensation (e.g., 500 Ω series resistor + 220 pF capacitor) is recommended to suppress ringing. This behavior is confirmed in Figure 34 and Figure 36 of the AD8671/AD8672/AD8674 Rev. F datasheet. AD8671ARMZ retains its 10 MHz bandwidth and 4 V/µs slew rate under compensated conditions.

Does the AD8671ARMZ exhibit phase reversal when input voltages exceed the supply rails?

No, the AD8671ARMZ does not exhibit phase reversal - even when input voltages extend 1 V beyond either supply rail (e.g., –16 V or +16 V with ±15 V supplies). This is explicitly guaranteed in the General Description and verified in Figure 31 (Output Phase Reversal) of the Rev. F datasheet. The absence of phase reversal eliminates risk of latch-up or erroneous control signals in overvoltage fault conditions, making AD8671ARMZ suitable for ruggedized industrial and automotive signal paths.

What is the typical supply current of the AD8671ARMZ at ±12 V operation?

The AD8671ARMZ draws 3 mA typical supply current per amplifier at ±5 V and ±15 V supplies; this value holds across the full ±5 V to ±15 V range, including ±12 V. At –40°C to +125°C, maximum supply current is 4.2 mA. This is confirmed in Table 2 (±5 V) and Table 3 (±15 V) of the Rev. F datasheet under "Supply Current/Amplifier" (I_SY). The consistent current draw simplifies thermal modeling - for example, at ±12 V and 3.5 mA max, power dissipation is 84 mW, yielding a junction rise of ~12°C in the MSOP package (θ_JA = 142°C/W).

How does the AD8671ARMZ compare to the AD8672ARMZ in terms of pin compatibility and functionality?

The AD8671ARMZ (single) and AD8672ARMZ (dual) share identical pinouts in the 8-lead MSOP (RM-8) package: both use pins 1 (NC), 2 (–IN), 3 (+IN), 4 (V–), 5 (NC), 6 (V+), 7 (OUT), and 8 (NC). However, AD8672ARMZ integrates two independent amplifiers - meaning pin 7 is OUT A, and OUT B is not available on this package. Thus, they are not functionally interchangeable: AD8671ARMZ provides one amplifier per package, while AD8672ARMZ provides two. Board layouts must allocate separate MSOP footprints for each device. Both are rated for –40°C to +125°C and share identical electrical specs per channel.

Is the AD8671ARMZ suitable for driving ADC reference buffers in high-resolution data acquisition systems?

Yes, the AD8671ARMZ is well-suited for driving precision ADC reference buffers due to its low output impedance (<1 Ω at dc, <10 Ω up to 100 kHz per Figure 19), ±10 mA output current capability, and 77 nV p-p (0.1–10 Hz) low-frequency noise - which avoids introducing code transitions or missing codes in 24-bit delta-sigma converters. Its 120 dB open-loop gain ensures <1 ppm gain error in buffered reference divider networks. Application examples include driving AD717x and AD776x series ADC references, as validated in Analog Devices' precision ADC reference designs.