Analog Devices Inc. AD8641ARZ-REEL7

Overview

AD8641ARZ-REEL7 from Analog Devices is a precision JFET-input operational amplifier optimized for low-power, rail-to-rail output applications. It delivers 250 µA max supply current, 1 pA max input bias current, and 750 µV max offset voltage across −40°C to +125°C, enabling high-accuracy signal conditioning in battery-powered instrumentation and photodiode amplifiers.

For engineers reviewing the AD8641ARZ-REEL7 datasheet, AD8641ARZ-REEL7 pinout, AD8641ARZ-REEL7 application, or AD8641ARZ-REEL7 equivalent, key selection criteria include ultra-low input bias current for high-impedance sensor interfaces, rail-to-rail output swing under single-supply operation (5 V to 26 V), and unity-gain stability with >500 pF capacitive load drive capability.

Technical Context

The AD8641ARZ-REEL7 employs a JFET input stage to achieve femtoampere-level input bias current, critical for photodiode and precision current-sensing circuits. Its rail-to-rail output stage supports full dynamic range utilization in single-supply systems, while internal compensation ensures unity-gain stability without external components.

It operates over ±2.5 V to ±13 V dual supply or 5 V to 26 V single supply, with guaranteed performance across −40°C to +125°C. Input common-mode range extends to the negative rail, and output swings within 50 mV of both rails at 1 mA load, supporting direct interfacing with CMOS DACs and ASICs.

Key Specifications

Pinout & Package

AD8641ARZ-REEL7 is housed in an 8-lead SOIC (R-8) package per JEDEC MS-012-AA, with exposed pad not present. Pin 1 is marked by a beveled corner or dot; device orientation follows standard SOIC top-view convention.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA376AIDBVR and LT1462ACS8#PBF, AD8641ARZ-REEL7 uniquely balances femtoampere input bias, micropower consumption, and rail-to-rail output-making it irreplaceable in photodiode amplifiers and multi-channel portable instrumentation where thermal and leakage constraints are dominant.

Availability

AD8641ARZ-REEL7 is available at Aetrix Electronics and suitable for photodiode amplifiers, precision current sensing, and medical instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD8641ARZ-REEL7 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 AD8641ARZ-REEL7 belongs to Analog Devices' precision JFET op-amp product line, engineered specifically for ultra-low input bias current and micropower operation in high-impedance, battery-constrained signal conditioning applications.

FAQ

What is the maximum capacitive load the AD8641ARZ-REEL7 can drive while remaining stable?

The AD8641ARZ-REEL7 remains stable with capacitive loads exceeding 500 pF, as confirmed in the datasheet's General Description and Typical Performance Characteristics. This allows direct driving of ADC input capacitors, long cables, or filtering networks without external isolation resistors-reducing component count and phase error in precision acquisition paths. Stability is maintained across its full operating temperature range.

Does the AD8641ARZ-REEL7 support true rail-to-rail input operation?

The AD8641ARZ-REEL7 features rail-to-rail *output*, but its input common-mode range extends only to the negative rail (VEE) and up to 3 V with a 5 V supply-not fully to VCC. On ±13 V supplies, input range is −13 V to +10 V. This partial rail-to-rail input enables ground-referenced sensor interfaces but requires level-shifting for signals near the positive rail. The AD8641ARZ-REEL7 datasheet explicitly defines these limits in Table 1 and Table 2.

What is the typical slew rate of the AD8641ARZ-REEL7 and how does it affect settling time?

The AD8641ARZ-REEL7 has a typical slew rate of 2 V/µs on 5 V supply and 3 V/µs on ±13 V supply. At unity gain, this supports 0.1% settling in under 1 µs for a 1 V step, as shown in Figure 35. For higher gains or larger steps, settling time increases linearly with output voltage swing-critical for multiplexed data acquisition where channel switching speed impacts throughput. The AD8641ARZ-REEL7's slew rate is sufficient for 100 kHz closed-loop bandwidths at moderate gains.

How does the AD8641ARZ-REEL7 perform in single-supply configurations below 5 V?

The AD8641ARZ-REEL7 is specified down to 5 V single supply; operation below 5 V is not characterized or guaranteed. Datasheet Absolute Maximum Ratings list minimum supply as 5 V (single) or ±2.5 V (dual). Attempting 3.3 V operation may result in degraded output swing, increased offset drift, or instability. For sub-5 V systems, consider purpose-designed low-voltage op-amps such as the AD8605, not the AD8641ARZ-REEL7.

Is the AD8641ARZ-REEL7 pin-compatible with other members of the AD864x family?

No-the AD8641ARZ-REEL7 (single amplifier, SOIC-8) is not pin-compatible with AD8642 (dual, SOIC-8 or MSOP-8) or AD8643 (quad, SOIC-14 or LFCSP-16). While all share functional similarity, pinouts differ significantly: AD8641ARZ-REEL7 uses pins 1–4 and 7–8, leaving pins 5–6 unconnected, whereas AD8642 assigns dedicated inputs/outputs to all eight pins. Interchanging them requires PCB redesign. Always verify pin mapping against the specific AD8641ARZ-REEL7 datasheet Figure 2.