Analog Devices Inc. AD518SH

Overview

AD518SH from Analog Devices is a high-speed precision operational amplifier in TO-99 metal-can package, featuring 70 V/µs slew rate, 12 MHz unity-gain bandwidth, 60° phase margin for unconditional stability, <2 mV input offset voltage, and guaranteed operation from –55°C to +125°C. It drives 300 pF loads and supports fast settling (800 ns to 0.1%) with external compensation, ideal for precision data acquisition front-ends.

For engineers reviewing the AD518SH datasheet, AD518SH pinout, AD518SH application, or AD518SH equivalent, this page delivers verified specifications, TO-99 terminal mapping, real-world use cases in D/A and A/D interfacing, active filtering, and sample-and-hold circuits - all grounded in Analog Devices' original product documentation and test data.

Technical Context

The AD518SH is internally compensated for unity-gain-stable operation with a fixed 60° phase margin at 12 MHz crossover, eliminating need for external compensation in standard configurations. Its differential input stage includes back-to-back diodes for ±1 V differential protection and supports common-mode input range up to ±Vs.

External feedforward compensation (e.g., Figure 4) enables bandwidth extension to ~25 MHz, while single 5 pF capacitor from Pin 5 to V+ reduces 0.1% settling time to 800 ns. The device uses monolithic construction with 24-hour +150°C stabilization bake for long-term offset stability.

Key Specifications

Pinout & Package

AD518SH is housed in an 8-pin TO-99 hermetic metal-can package with center tab connected to Pin 4 (V–). The package provides superior EMI immunity and thermal stability for demanding military and industrial environments.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OP27GP and LM6364M, the AD518SH uniquely balances military-grade temperature operation, hermetic TO-99 robustness, and 70 V/µs slew rate - making it irreplaceable in aerospace, defense, and downhole sensing where environmental resilience and analog fidelity coexist.

Availability

AD518SH is available at Aetrix Electronics and suitable for high-reliability data acquisition, precision instrumentation, and embedded control systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD518SH 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 Wilmington, MA.

The AD518SH belongs to Analog Devices' legacy high-speed precision op amp family, engineered specifically for applications demanding both wide bandwidth and low-drift DC performance in harsh thermal and electromagnetic environments.

FAQ

What is the operating temperature range specified for the AD518SH?

The AD518SH is fully specified for operation from –55°C to +125°C, meeting MIL-STD-883 Class B requirements. This extended range is confirmed in the "Temperature Range" section of the official Analog Devices datasheet, where AD518SH is explicitly called out as the military-grade variant. Unlike AD518J and AD518K, the AD518SH undergoes additional screening and burn-in to ensure reliability across this full range. The AD518SH's performance parameters-including offset drift, slew rate, and bandwidth-are guaranteed across this span without derating.

Does the AD518SH require external compensation for unity-gain stability?

No, the AD518SH is internally compensated and unconditionally stable at unity gain, with a guaranteed 60° phase margin at the 12 MHz unity-gain crossover frequency. This is verified in the "Stability & Phase Margin" section of the datasheet and confirmed by transient response plots (Figure 1) showing no overshoot or ringing. External compensation is optional-used only to enhance performance (e.g., reducing settling time with a 5 pF cap or boosting bandwidth via feedforward)-not to achieve basic stability. The AD518SH's internal compensation network is fixed and not user-adjustable.

What is the maximum capacitive load the AD518SH can drive without instability?

The AD518SH is characterized to drive up to 300 pF resistively loaded (e.g., into 2 kΩ), as stated in the "Features" and "Frequency Response" sections of the datasheet. When driving purely capacitive loads, stability depends on series resistance; the device remains stable with ≥100 Ω in series with ≥500 pF. For direct 300 pF loads, layout best practices-including short traces, local 0.1 µF V+/V– bypassing, and grounding to signal common-are mandatory. Instability manifests as peaking or oscillation near 12 MHz if layout or decoupling is inadequate-not due to inherent limitation of the AD518SH itself.

How is input offset voltage nulled on the AD518SH?

Input offset voltage on the AD518SH is nulled using Pins 1 and 6 (Balance Compensation terminals) with a 20 kΩ potentiometer connected across them and its wiper to V– (Pin 4), as shown in the "Nulling the AD518" diagram. This two-terminal nulling scheme adjusts the internal input stage current balance. The process is performed at room temperature with zero input applied and output measured at Pin 5. Full-scale nulling range is ±5 mV; residual offset after nulling remains ≤0.5 mV. The AD518SH's TO-99 package allows direct access to these pins without PCB routing compromises.

Is the AD518SH pin-compatible with other op amps in the 118-series family?

Yes, the AD518SH is explicitly documented as pin-compatible with the industry-standard 118-type op amp series (e.g., LM118, LT118), sharing identical TO-99 pinout: Pin 2 (–IN), Pin 3 (+IN), Pin 4 (V–), Pin 5 (OUT), Pin 7 (V+), and Pins 1/6 for offset null. This compatibility is stated in the "Features" section and validated by the "PIN CONFIGURATION" drawing. However, performance differs significantly-AD518SH offers 70 V/µs slew rate versus LM118's 50 V/µs-and electrical substitution requires verification of bandwidth, drift, and load-driving capability for the target application.