Analog Devices Inc. AD823AARZ

Overview

AD823AARZ from Analog Devices is a dual-channel, JFET-input operational amplifier optimized for precision wideband signal conditioning in single- or dual-supply systems. It delivers 17 MHz −3 dB bandwidth (G = +1), 30 V/μs slew rate, rail-to-rail output swing within 20 mV of rails at ≤100 μA load, and 700 μV max input offset voltage - enabling high-fidelity photodiode preamplification and active filter design in medical instrumentation and data acquisition.

For engineers reviewing the AD823AARZ datasheet, AD823AARZ pinout, AD823AARZ application, or AD823AARZ equivalent, key selection considerations include its 14–19 MHz bandwidth across 3 V to ±18 V supplies, 0.6 pF differential input capacitance for photodiode interface stability, 40 mA linear output drive capability, and guaranteed operation over −40°C to +85°C industrial temperature range.

Technical Context

The AD823AARZ employs an N-channel JFET input stage fabricated on Analog Devices' XFCB process, supporting input voltages down to 0.2 V below −VS and delivering sub-picoamp bias current (0.3 pA typ). Its rail-to-rail bipolar output stage provides 40 mA linear drive with <33 Ω saturation resistance and maintains stability driving ≥500 pF capacitive loads in unity-gain configuration.

This architecture enables simultaneous high dc precision (1 μV/°C offset drift, 10¹³ Ω input resistance) and ac performance (14 nV/√Hz input voltage noise at 10 kHz, −108 dBc SFDR at 20 kHz), making it suitable for low-noise, high-dynamic-range transimpedance amplifiers where source impedances exceed 1 GΩ.

Key Specifications

Pinout & Package

AD823AARZ is housed in an 8-lead SOIC_N (Small Outline Integrated Circuit, Narrow) package with standard JEDEC MS-012AC footprint and 1.27 mm lead pitch. Thermal resistance θ_JA is 120°C/W in typical PCB layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA2134PA and TL072CDR, AD823AARZ uniquely combines 17 MHz bandwidth, rail-to-rail output, sub-picoamp bias current, and <1 pF input capacitance - making it the only option among the three capable of stable, high-fidelity transimpedance amplification at >2 MHz with 1 GΩ+ source impedance.

Availability

AD823AARZ is available at Aetrix Electronics and suitable for photodiode preamplifiers, active filters, and precision instrumentation requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for AD823AARZ 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, with R&D and manufacturing facilities worldwide.

The AD823A product line targets precision, wideband signal conditioning in low-noise, high-impedance sensor interfaces - specifically engineered for photodiode preamps, medical instrumentation, and 12–16-bit data acquisition systems operating from 3 V to ±18 V supplies.

FAQ

What is the maximum capacitive load the AD823AARZ can drive stably in unity-gain configuration?

The AD823AARZ is characterized to drive ≥500 pF directly in G = +1 configuration without external compensation, maintaining ≥35° phase margin. This capability is verified in Figure 36 of the Rev. B datasheet with 470 pF load and confirmed across supply voltages from 3 V to ±15 V. For loads exceeding 500 pF, a series output resistor (per Figure 28) or increased closed-loop gain improves stability. The AD823AARZ's integrator capacitor and low-frequency output impedance (<0.01 Ω) prevent instability even under heavy capacitive loading.

Does the AD823AARZ exhibit phase reversal when input voltage exceeds the positive supply rail?

No - the AD823AARZ does not exhibit phase reversal for input voltages up to and including +VS, as confirmed in Figure 39 of the datasheet. When driven beyond +VS (e.g., +VS + 1 V), internal junctions forward-bias and input current reverses direction (Figure 11), but output polarity remains correct. To prevent damage during sustained overvoltage, a 1 kΩ series resistor is recommended if input may exceed +VS by >300 mV or fall below −VS by >300 mV for more than 10 seconds.

What is the input common-mode voltage range of the AD823AARZ at 3.3 V single supply?

At +VS = 3.3 V, the AD823AARZ input common-mode voltage range is −0.2 V to +1.8 V (Table 2, page 4), extending 0.2 V below ground and 1.5 V below the positive rail. This allows direct interfacing with sensors referenced to ground or negative bias while maintaining specified offset and CMRR performance. Operation outside this range degrades bandwidth and increases common-mode error but does not cause phase reversal.

How does the AD823AARZ's input bias current compare to other dual JFET op amps, and why does it matter?

The AD823AARZ specifies 0.3 pA typical input bias current (25 pA max), significantly lower than alternatives like TL072CDR (30 pA typ) or OPA2134PA (10 pA typ). This ultra-low bias current minimizes voltage error across high-impedance sources - e.g., a 1 GΩ photodiode shunt resistor contributes only 0.3 mV DC offset. In precision instrumentation, this enables accurate DC-coupled measurements without guard traces or active bias cancellation circuits.

Can the AD823AARZ operate from a 3 V single supply while maintaining rail-to-rail output swing?

Yes - the AD823AARZ is fully specified for 3 V single supply (Table 2, page 4). At +VS = 3 V and −VS = 0 V, output swing reaches 0.006 V to 3.28 V at ±100 μA load, i.e., within 6 mV of ground and 22 mV of +3 V. Linear output current remains 40 mA within 0.5 V of either rail (0.5 V to 2.5 V), enabling full utilization of 3 V ADC reference ranges. Input common-mode extends to −0.2 V, supporting level-shifting from negative sensor outputs.