Analog Devices Inc. AD8513AR

Overview

AD8513AR from Analog Devices is a quad precision JFET operational amplifier optimized for high-impedance sensor signal conditioning and low-noise current measurement. It delivers 400 μV max offset voltage, 8 nV/√Hz voltage noise at 1 kHz, 20 V/μs slew rate, and operates from ±5 V to ±15 V supplies across −40°C to +125°C. It is used in photodiode amplifiers and precision instrumentation front-ends.

For engineers reviewing the AD8513AR datasheet, AD8513AR pinout, AD8513AR application, or AD8513AR equivalent, key selection criteria include input bias current (25 pA typ at ±15 V), unity-gain stability with capacitive loads up to 1000 pF, 0.5 μs settling time to 0.1%, and guaranteed operation over extended industrial temperature range.

Technical Context

The AD8513AR employs a JFET-input architecture enabling ultra-low input bias current and minimal input capacitance (12.5 pF differential), critical for high-Z sensor interfaces. Its internal compensation ensures unity-gain stability without external components, even with 500 pF load capacitance.

It features no phase reversal under input overvoltage conditions and maintains fast overload recovery (<200 ns), supporting robust operation in transient-rich environments such as multipole filter stages and precision I-V conversion circuits.

Key Specifications

Pinout & Package

AD8513AR is supplied in a 14-lead SOIC_N (R suffix) package with standard JEDEC outline, 1.27 mm pitch, and 8.65 mm × 3.90 mm footprint. Thermal resistance θ_JA is 120°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA4134UA and LT1028CSW, AD8513AR uniquely balances quad-channel integration, 25 pA input bias, and 8 nV/√Hz noise - making it optimal for space-constrained, high-impedance multichannel systems like portable diagnostic equipment and multi-sensor data loggers.

Availability

AD8513AR is available at Aetrix Electronics and suitable for precision instrumentation, medical device design, and industrial sensor signal conditioning requiring stable component supply and long-term lifecycle support.

Supply support for AD8513AR 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 AD851x family was designed specifically for precision DC-coupled applications demanding low offset, ultra-low input bias current, and wide bandwidth - targeting instrumentation, test equipment, and high-fidelity sensor interfaces.

FAQ

What is the maximum capacitive load the AD8513AR can drive stably in unity gain?

The AD8513AR is unconditionally stable driving up to 1000 pF in unity-gain configuration without external compensation. With a 500 pF load, overshoot is reduced from 55% to <3% using a 100 Ω series resistor and 1 nF capacitor snubber network. This capability simplifies photodiode TIA and filter design without sacrificing output swing or requiring layout iterations. The AD8513AR datasheet confirms stability across the full −40°C to +125°C range.

Does the AD8513AR exhibit phase reversal when input voltages exceed the supply rails?

No, the AD8513AR does not suffer from output phase reversal when input voltages exceed the common-mode range - a known failure mode in older JFET op-amps. Its internal protection circuitry safely handles inputs up to 0.7 V beyond the rails without polarity inversion or latch-up. This behavior is verified in Figure 40 of the AD8513AR datasheet and ensures reliable operation in sensor interfaces subject to ESD or transient overvoltage.

What is the typical input bias current of the AD8513AR at ±5 V supply?

The AD8513AR exhibits 21 pA typical input bias current at ±5 V supply and 25 pA at ±15 V, as specified in Table 1 of the AD8513AR datasheet. This ultra-low value remains stable across temperature (≤7.5 nA at +125°C), enabling accurate amplification of signals from high-impedance sources such as piezoelectric sensors, pH electrodes, and photodiodes without significant current-induced offset errors.

Can the AD8513AR be used in single-supply configurations?

The AD8513AR is specified for dual-supply operation from ±5 V to ±15 V and is not characterized for true single-supply use (e.g., 0 V to +10 V). Its input voltage range is asymmetric (e.g., −2.0 V to +2.5 V at ±5 V), and output swing does not rail-to-rail. For single-supply applications, consider rail-to-rail input/output op-amps like the AD8605 family. The AD8513AR datasheet provides no performance data for V– = 0 V operation.

How does the AD8513AR's noise performance compare between 10 Hz and 1 kHz?

The AD8513AR's voltage noise density decreases from 34 nV/√Hz at 10 Hz to 8.0 nV/√Hz at 1 kHz, reflecting dominant 1/f noise at low frequencies and white noise dominance above ~100 Hz. Its 0.1–10 Hz peak-to-peak noise is 2.4–5.2 μV p-p, critical for DC precision applications. This spectral profile is documented in Figures 23–25 and Table 1 of the AD8513AR datasheet, confirming suitability for both low-frequency sensor conditioning and higher-bandwidth signal chains.