Analog Devices Inc. AD648KRZ

Overview

AD648KRZ from Analog Devices is a dual precision, low-power BiFET operational amplifier in an 8-lead SOIC package, delivering 1 MHz unity-gain bandwidth, 1.8 V/µs slew rate, and ≤1 mV input offset voltage (AD648K grade) with 10 µV/°C max drift. It operates from ±4.5 V to ±18 V supplies, draws ≤400 µA quiescent current per amplifier, and targets high-impedance, battery-powered instrumentation front ends and CMOS DAC buffers.

For engineers reviewing the AD648KRZ datasheet, AD648KRZ pinout, AD648KRZ application, or AD648KRZ equivalent, key selection criteria include guaranteed low bias current (≤10 pA warmed up), laser-trimmed dc precision, dual-amplifier matching (≤2 mV offset match), and SOIC surface-mount compatibility for space-constrained analog signal conditioning.

Technical Context

The AD648KRZ integrates two matched JFET-input op amps on a single die using ion-implanted FET and laser wafer trimming. Its input stage delivers ultra-low bias current over full common-mode range (±11 V), while open-loop gain ≥700 V/mV (RL ≥ 10 kΩ) supports 12-bit linearity in high-Z buffer configurations.

Designed for dual-supply operation, it features 82 dB min CMRR (B-grade), –120 dB crosstalk at 1 kHz, and 2 µV p-p 0.1 Hz–10 Hz input voltage noise - enabling stable performance in precision photodiode preamps and log-ratio amplifiers where self-heating and leakage-induced errors must be minimized.

Key Specifications

Pinout & Package

AD648KRZ is housed in an 8-lead SOIC (R-8) package, 3.9 mm × 4.9 mm body, 1.27 mm lead pitch, compliant with JEDEC MS-012 AA. Thermal resistance θ_JA = 160°C/W, θ_JC = 42°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL062CDR and OP27GS, AD648KRZ uniquely balances sub-10 pA bias current, ≤1 mV offset, ≤10 µV/°C drift, and ≤400 µA total supply current - making it the only dual op amp qualified for simultaneous high-Z sensor interfacing and multi-day battery operation in portable instrumentation.

Availability

AD648KRZ is available at Aetrix Electronics and suitable for precision instrumentation front ends, battery-powered medical sensors, and industrial DAC output buffering requiring stable component supply across extended temperature ranges (–40°C to +85°C).

Supply support for AD648KRZ 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, founded in 1965 and headquartered in Wilmington, MA.

The AD648 product line was engineered specifically for dual-channel, low-power precision analog signal conditioning - targeting applications where laser-trimmed dc accuracy, ultra-low input current, and SOIC manufacturability converge in legacy industrial and test equipment.

FAQ

What is the maximum operating temperature range for AD648KRZ?

The AD648KRZ is rated for industrial temperature operation from –40°C to +85°C. This rating is explicitly defined in the datasheet for the "K" grade variant and applies to all electrical specifications unless otherwise noted. The device maintains guaranteed performance across this full range, including input offset voltage ≤3.0 mV and bias current ≤10 pA (warmed up) at +85°C. Operation beyond +85°C is not characterized and may result in parametric degradation.

Does AD648KRZ support single-supply operation?

AD648KRZ is specified and optimized for dual-supply operation (±4.5 V to ±18 V). While it can function with asymmetric supplies (e.g., +15 V and ground), true single-supply operation (e.g., 0 V and +15 V) is not supported - its input common-mode range extends only to within ~1 V of the positive rail and ~3 V above the negative rail. For single-supply applications, the AD648KRZ requires level-shifting circuitry or a negative charge pump to establish a virtual ground, as confirmed by its ±11 V common-mode specification relative to V+ and V–.

Is AD648KRZ pin-compatible with other dual op amps?

Yes, AD648KRZ uses the industry-standard 8-pin SOIC dual op amp pinout (Pin 1: A-invert, Pin 2: A-noninv, Pin 3: A-out, Pin 4: V–, Pin 5: B-noninv, Pin 6: B-invert, Pin 7: B-out, Pin 8: V+), matching LF442, TL062, and AD642. This allows direct replacement in existing layouts without PCB modification, provided supply rails, loading, and thermal constraints remain within AD648KRZ's specifications - particularly its lower quiescent current and higher input impedance.

What is the guaranteed input bias current for AD648KRZ after warm-up?

The AD648KRZ guarantees ≤10 pA maximum input bias current for either amplifier after five minutes of operation at +25°C, as specified for the "K" grade in the warmed-up condition. This value holds across the full common-mode voltage range (±11 V) and is validated per Analog Devices' laser-trimming process. At +85°C, bias current increases to ≤0.65 nA due to JFET thermal doubling every 10°C - a design-critical parameter for photodiode and electrometer applications.

How does AD648KRZ handle input overvoltage conditions?

AD648KRZ is guaranteed to withstand input voltages equal to its supply rails (±18 V absolute max), but exceeding the negative supply voltage on either input forward-biases the substrate junction and may cause permanent damage. Phase reversal occurs if inputs exceed the negative common-mode limit (–11 V), forcing output high. To protect against faults like sensor shorts, external current-limiting resistors (e.g., 100 kΩ) are recommended - as detailed in Figure 23b - since the internal ESD protection is not rated for sustained overvoltage stress.