Analog Devices Inc. AD847AQ

Summary of AD847AQ Universal Monolithic Operational Amplifier

The Analog Devices AD847AQ stands out in the landscape of high-speed, general-purpose operational amplifiers—delivering an ideal combination of ac and dc performance for demanding analog signal processing tasks. Housed in an 8-lead ceramic dual-in-line (CERDIP) package, the AD847AQ is engineered for resilience and broad usability, suiting both industrial and high-reliability military applications with a -40°C to +85°C operating temperature range. At its core, this device offers a high gain-bandwidth product, robust slew rate, and low power consumption, making it an attractive choice for engineers and sourcing professionals whose systems demand quality amplification without compromise.

Main Electrical Specifications and Performance Metrics of the AD847AQ

The AD847AQ leverages advanced monolithic architecture to achieve superior dynamic and static parameters. Among its distinguishing features:

Unity-gain bandwidth: Up to 50 MHz (±15 V supply), providing confidence in high-frequency applications.

High slew rate: 300 V/μs (typical at ±15 V), which enables accurate amplification of fast transient signals, crucial in data acquisition and video systems.

Output voltage swing: ±12 V into 1 kΩ (±15 V supplies), accommodating a wide dynamic range.

Input offset voltage: 0.5 mV (typical), ensuring minimal dc error.

Low input bias current: 3.3 μA (typical), beneficial in high-impedance signal paths.

Open-loop gain: 5.5 V/mV (typical, RL = 1 kΩ).

Settling time to 0.1%: 65 ns for a 10 V step, supporting precise step response needs in DAC/ADC buffer stages.

Differential gain and phase: 0.04% / 0.19° (NTSC/PAL), specifically targeting video performance requirements.

Excellent common-mode rejection: ≥78 dB, critical for noisy environments.

Power supply rejection: up to 98 dB, giving robust tolerance to line voltage fluctuations.

Quiescent supply current: Typically 5.3 mA at ±15 V, supporting low power operation in dense designs.

Its wide supply range (±4.5 V to ±18 V) offers flexibility for integration into both traditional ±15 V and modern ±5 V or single-rail architectures.

AD847AQ Pinout, Packaging Choices, and Thermal Management

For seamless system integration, the AD847AQ is supplied in the industry-standard 8-lead CERDIP footprint, with pinout optimized for straightforward PCB layout. The configuration is as follows: pins for inverting and non-inverting inputs, output, supply rails, and optional offsets (null) for fine-trimming input balance. The ceramic package ensures low thermal resistance, enhancing stability under varying load and ambient temperatures.

Thermal derating is an important consideration; the device supports a maximum junction temperature of 175°C, with the CERDIP package rated at 1.1 W power dissipation. Additionally, the AD847AQ features enhanced ESD protection circuitry, although conventional best practices for handling sensitive analog ICs remain essential to avoid latent reliability risks. Storage and soldering temperature ranges are also specified for robust assembly processes.

AD847AQ Application Examples and Engineering Guidelines

The AD847AQ is particularly suited to applications requiring both speed and precision. Key domains include:

Video processing and high-speed cable drivers, utilizing the amplifier’s bandwidth, phase fidelity, and low differential gain/phase distortion for NTSC/PAL compatibility.

High-speed data acquisition and conversion, such as buffer amplifiers for DACs and flash ADCs. The device supports rapid full-power pulse response (12.7 MHz at ±5 V).

Imaging systems—copiers, fax machines, cameras—where precise analog front-end integrity is mandatory.

Multi-pole active filters and other high-density analog signal chains benefiting from low supply current and small package.

Systems susceptible to load or capacitive-driving instability, as the AD847AQ is internally compensated for unity-gain operation and can reliably drive any capacitive load.

In these and similar scenarios, engineers can take advantage of the amplifier’s fast settling and high current output (up to 32 mA short-circuit), promoting high drive capability without the risk of oscillation.

Comparative Analysis and Distinct Benefits of AD847AQ Versus Competing Products

While numerous op amps serve the general-purpose category, the AD847AQ delivers tangible advantages in applications where bandwidth, settling time, and low power converge as critical metrics. Unlike legacy video amplifiers (such as HA2544 or EL2020), the AD847AQ assures superior differential gain/phase control, lower offset for precision tasks, and a minimal quiescent current profile favorable for power-budgeted systems.

Moreover, the AD847AQ supports both ±5 V and ±15 V operation with verified performance across its full rated temperature range. Its enhanced drive capability into low-impedance loads and consistent frequency/phase response under varying supply conditions distinguish it from many competing op amps defined purely for one domain (e.g., only video or only high-speed data).

Alternative or Substitute Models for the AD847AQ

Evaluating alternative or equivalent models remains a key step in procurement and design-ins to mitigate supply chain risks or optimize cost-performance. Engineers seeking close drop-in equivalents or functional replacements for the Analog Devices AD847AQ may consider:

Analog Devices AD827: A dual version providing similar electrical performance in an 8-lead package for higher channel density.

Texas Instruments LM6361: A pin-compatible amplifier often specified as an enhanced replacement for legacy circuits, with comparable slew rate and bandwidth.

Elantec (now Renesas) EL2020: Offers similar high-speed performance parameters, but may require careful analysis for equivalency—especially regarding offset, drive capacity, and package resilience.

Harris/Intersil HA2544, HA2520 series: Older-generation amplifiers that may be appropriate for replacement in legacy or cost-driven designs, with a note on performance limitations when compared to the AD847AQ.

A detailed review of application-specific needs—especially concerning supply voltage tolerances, output drive, and video system requirements—is recommended before final selection.

Conclusion

In summary, the Analog Devices AD847AQ brings a high-performance, general-purpose op amp solution ideal for engineers and procurement professionals addressing demanding analog signal amplification. Blending high slew rate, robust bandwidth, low input offset, and efficient power consumption within a rugged CERDIP package, the AD847AQ is recognized for its versatility across video, instrumentation, and high-speed buffer applications. With a strong foundation in reliable analog design, and an ecosystem supporting alternative solutions, the AD847AQ continues to be a reference choice for next-generation analog circuits.