Analog Devices Inc. LT1112IS8#PBF

LT1112IS8#PBF Dual Precision Op Amp Product Summary

The LT1112IS8#PBF, manufactured by Analog Devices Inc., is a dual-channel general-purpose operational amplifier integrated in an 8-lead Small Outline (SO-8) surface-mount package. This device is part of the LT1112/LT1114 family, renowned for combining high-precision specifications with cost-effectiveness, targeting demanding analog applications where low offset voltage, low drift, and excellent matching are essential. Its design ensures compatibility with a broad range of existing precision op amp footprints, offering seamless replacement in instrumentation, industrial, and battery-powered systems.

Key Attributes and Performance Indicators of LT1112IS8#PBF

At the heart of the LT1112IS8#PBF's value proposition is its combination of exceptional DC accuracy and low power consumption. Prime performance figures include a maximum input offset voltage of 60μV (prime grade) or 75μV (standard grade), with an offset voltage drift kept to a maximum of 0.5μV/°C. The amplifier features a remarkably low input bias current of 250pA (max), and a 0.1Hz to 10Hz input noise of just 0.3μV peak-to-peak and 2.2pA peak-to-peak, making it highly suitable for low-frequency and high-impedance sensor applications.

Other notable specifications include:

Supply Current: 400μA max per amplifier, ideal for portable and battery-powered instruments.

Common-Mode Rejection Ratio (CMRR): 120dB minimum ensures excellent disturbance rejection.

Open-Loop Voltage Gain: 1 million minimum, supporting high-accuracy amplification.

Guaranteed operation with supply voltages as low as ±1.0V, enabling flexibility even with low-battery scenarios.

SO-8 packaging with standard pinout for straightforward integration.

Furthermore, the LT1112IS8#PBF provides full matching specifications between the two amplifiers in a package, which is critical for precision bridge, instrumentation, and filter circuits where amplifier matching directly impacts system accuracy.

Electrical Specifications and Absolute Limit Ratings for LT1112IS8#PBF

The LT1112IS8#PBF is characterized for operations with supply voltages up to ±20V, with all electrical performance specified at ±15V and TA=25°C unless otherwise noted. The component is robust, with the following absolute maximum ratings:

Differential Input Voltage: ±20V

Differential Input Current: ±10mA

Output Short Circuit Duration: Indefinite

Storage Temperature Range: -65°C to 150°C

Package Lead Soldering Temperature: 300°C for 10 seconds

Operating Temperature Range: -40°C to 85°C (for industrial-grade versions including LT1112IS8#PBF)

Extensive on-chip input and output protection measures, such as back-to-back diodes, prevent damage from overvoltages in typical operating scenarios.

Application Compatibility and Suggested Usage Scenarios for LT1112IS8#PBF

The LT1112IS8#PBF excels in applications such as picoampere/microvolt instrumentation, two- and three-op amp instrumentation amplifiers, thermocouple and bridge amplifiers, low-frequency active filters, and photo-current amplifiers. Its ultra-low offset/drift parameters, together with high-matching accuracy, facilitate superior common-mode rejection and low error voltage—essential for high-resolution sensor analog front-ends and differential measurement circuits.

In battery-powered systems, the device’s low supply current and guaranteed specifications at supply voltages as low as ±1.0V (allowing operation down to nearly depleted AA cells) make it particularly advantageous.

Typical circuit implementations might include:

Dual buffered voltage references for precision analog biasing in low-voltage systems.

High-source-impedance signal conditioning, leveraging the amplifier’s low bias current and input noise.

Active filters and integrators for precision biomedical or scientific instrumentation.

Packaging Details and Physical Specifications of LT1112IS8#PBF

The LT1112IS8#PBF is offered in the 8-lead SO-8 plastic surface-mount package, compatible with industry-standard footprints. The SO-8 format provides a blend of minimal PCB real estate consumption and robust, reliable connections for automated assembly. Pin assignments are identical to legacy dual op amps, supporting straightforward drop-in replacement for both new designs and upgrades to older systems. Detailed mechanical drawings are available for precise board layout integration.

Technical Factors and Design Guidelines for LT1112IS8#PBF

A notable design feature of the LT1112IS8#PBF is its implementation of comprehensive input and output protection, ensuring ruggedness during common transient events. When the amplifier is operated as a voltage follower and input signals exceed the common-mode range, the output cleanly clips without phase inversion—a behavior contrasted with certain competitive devices such as the OP-297. This results in predictable, safe operation even under over-drive situations.

For circuits requiring high amplifier matching, such as three-op-amp instrumentation amplifiers or tracking voltage references, the guaranteed matching of offset voltage and drift between the two amplifiers is critical. Here, system-level errors are directly minimized by the inherent matching, improving measurement reliability without the need for external trimming.

Engineers should take care with fast large-signal pulses at the input; in certain follower configurations, using a feedback resistor can expedite output recovery by protecting the input diodes and limiting current.

Additionally, board layout can influence high-impedance performance due to parasitic capacitance between package pins. When using dual op amp packages in high-source-resistance instrumentation, consider potential mismatches this can introduce versus quad packages, especially at higher frequencies.

Alternative or Comparable Substitutes for LT1112IS8#PBF

The LT1112IS8#PBF is designed to be a direct replacement for many legacy and competing dual precision op amps. It is pin-compatible with, and provides superior or equivalent performance to:

OP-200, OP-297, and AD706 dual precision op amps.

For designs based on quad configurations, the companion LT1114 serves as a direct replacement for OP-400, OP-497, and AD704 quads.

This ease of interchangeability supports maintenance and supply-chain security for both legacy and new designs, and allows direct footprint and performance upgrades without major PCB revisions.

Conclusion

For engineers and procurement specialists seeking a dual op amp solution that blends high precision, ultra-low input errors, robust performance across temperature, and energy efficiency, the LT1112IS8#PBF from Analog Devices stands out. Its combination of thorough matching specifications, supply voltage flexibility, and rugged protection features enable advanced performance in instrumentation, medical, scientific, and industrial sensor applications. The LT1112IS8#PBF’s compatibility with established industry-standard packages and established equivalents assures both forward-looking design and longstanding support for critical analog channels.