Analog Devices Inc. AD8625ARZ

Overview

AD8625ARZ from Analog Devices is a precision quad JFET-input operational amplifier optimized for low-noise, low-input-bias-current signal conditioning in single- or dual-supply systems. It delivers rail-to-rail output swing, 5 MHz gain bandwidth, 5 V/µs slew rate, and 500 µV max offset voltage across –40°C to +85°C - enabling high-fidelity photodiode amplification and DAC output buffering in battery-powered instrumentation.

For engineers reviewing the AD8625ARZ datasheet, AD8625ARZ pinout, AD8625ARZ application, or AD8625ARZ equivalent, key selection criteria include verified picoampere input bias current (≤1 pA), guaranteed rail-to-rail output drive into ≥1 kΩ loads, industrial temperature operation, and compatibility with photodiode transimpedance and precision filter topologies requiring minimal DC error.

Technical Context

The AD8625ARZ employs an n-channel JFET input stage delivering true single-supply operation from 5 V to 26 V (or ±2.5 V to ±13 V), with input common-mode range extending 0.2 V below V– and 2 V below V+. Its bipolar rail-to-rail output stage achieves ≤5 mV saturation voltage at 2 mA load, while maintaining stability with capacitive loads >500 pF and unity-gain configuration.

Designed for low-noise, high-impedance source interfacing, it features 17.5 nV/√Hz voltage noise density (1 kHz), 0.4 fA/√Hz current noise density, and 104 dB channel separation - making it suitable for multi-channel precision analog front-ends where crosstalk and Johnson noise must be minimized.

Key Specifications

Pinout & Package

AD8625ARZ is housed in a 14-lead SOIC (R package) with standard quad op amp pinout and no internal connections on pins 1, 13, and 14 (NC). Thermal resistance θ_JA = 120°C/W supports reliable operation at full rated supply and load conditions.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA4141AIPW and LT1492CN#PBF, AD8625ARZ uniquely balances ultra-low input bias current (≤1 pA), rail-to-rail output, and 5 MHz bandwidth in a 14-lead SOIC - making it the preferred choice for multi-channel, battery-conscious, high-impedance sensor systems requiring both precision and moderate speed.

Availability

AD8625ARZ is available at Aetrix Electronics and suitable for photodiode amplification, line-powered instrumentation, and automotive sensor interface applications requiring stable component supply, long-lifecycle support, and guaranteed industrial temperature performance.

Supply support for AD8625ARZ 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 AD862x family was designed specifically for precision, low-power, single-supply signal conditioning in instrumentation, sensor interfaces, and portable test equipment - emphasizing picoampere input bias, rail-to-rail output, and robust industrial temperature operation.

FAQ

What is the maximum capacitive load the AD8625ARZ can drive while remaining stable?

The AD8625ARZ is characterized for stable operation with capacitive loads exceeding 500 pF in unity-gain configuration, as confirmed in the datasheet's Typical Performance Characteristics (Figure 31 and Figure 32). This capability eliminates the need for external isolation resistors when driving ADC input filters, coaxial cables, or multi-pole active filters - directly supporting robust signal chain design without added phase margin compensation.

Does the AD8625ARZ exhibit phase reversal when input voltages exceed the positive supply rail?

No, the AD8625ARZ does not exhibit phase reversal under any condition, including when input voltages exceed V+ by up to 300 mV - a behavior explicitly verified in Figure 29 of the datasheet. This intrinsic immunity removes the need for external clamping diodes in sensor front-ends exposed to transient overvoltages, simplifying protection circuitry and improving reliability in automotive and industrial environments.

Can the AD8625ARZ operate from a single 3.3 V supply?

Yes, the AD8625ARZ supports true single-supply operation down to 5 V minimum, so it cannot be used with a 3.3 V supply. The absolute minimum total supply voltage is 5 V (e.g., V+ = 3.3 V and V– = –1.7 V is invalid); valid configurations include 5 V (V+ = 5 V, V– = 0 V) or higher. Attempting 3.3 V operation violates Absolute Maximum Ratings and will result in undefined performance or damage.

What is the typical supply current for the AD8625ARZ at 25°C and 5 V supply?

The AD8625ARZ draws 630 µA per amplifier at 25°C and 5 V supply, resulting in a total quiescent current of approximately 2.52 mA for all four channels. This value is confirmed in Table 1 (Electrical Characteristics) of the Rev. F datasheet and remains below 3.2 mA across the full –40°C to +85°C industrial temperature range, enabling efficient use in power-sensitive portable instrumentation.

How does the AD8625ARZ handle input signals near the negative supply rail?

The AD8625ARZ supports input common-mode voltages down to 0.2 V below V–, allowing valid operation with signals extending slightly below ground in single-supply systems. Its JFET input stage maintains picoampere-level bias current across this range, as shown in Figure 41–Figure 43, making it suitable for interfacing with sensors whose outputs swing negative relative to system ground - such as certain bridge configurations or electrochemical cells.