Analog Devices Inc./Maxim Integrated MAX412CSA+

Overview

The MAX412CSA+ from Maxim Integrated is a dual, precision, low-noise operational amplifier optimized for high-speed, low-voltage systems. It delivers 2.4nV/√Hz input voltage-noise density at 1kHz, 28MHz unity-gain bandwidth, and 4.5V/µs slew rate while operating from ±2.4V to ±5V supplies and consuming only 2.5mA per amplifier. It is used in ultra-low-noise instrumentation amplifiers and infrared detector front-ends.

For engineers reviewing the MAX412CSA+ datasheet, MAX412CSA+ pinout, MAX412CSA+ application, or MAX412CSA+ equivalent, key selection criteria include its guaranteed 2.4nV/√Hz noise floor at 1kHz, ±250µV max input offset voltage (C-grade), SO-8 package compatibility, and stability driving up to 3900pF capacitive loads in unity-gain configuration.

Technical Context

The MAX412CSA+ employs a bipolar input stage engineered for optimal trade-off between voltage noise and current noise - achieving sub-2.4nV/√Hz performance without sacrificing DC accuracy or AC stability. Its design avoids input current-limiting resistors to preserve noise performance, relying instead on back-to-back clamp diodes for ±0.1V differential input protection.

It supports single-supply operation down to 4.8V total supply, maintains 115dB min open-loop gain and 135dB channel separation at 1kHz, and remains unity-gain stable with output swing of ±3.6V into 2kΩ from ±5V rails - enabling use in precision signal conditioning where rail-to-rail output is not required but low distortion and wide dynamic range are critical.

Key Specifications

Pinout & Package

The MAX412CSA+ is housed in an 8-pin SO (Small Outline) package with standard dual op-amp pinout and exposed pad not connected internally. Pin 1 is OUT1, Pin 2 is IN1−, Pin 3 is IN1+, Pin 4 is V−, Pin 5 is IN2+, Pin 6 is IN2−, Pin 7 is OUT2, and Pin 8 is V+.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual low-noise op amp applications.

Compared with OPA211IDR and AD8620ARZ, the MAX412CSA+ offers the optimal balance of ultra-low noise (2.4nV/√Hz), low quiescent current (2.5mA), and proven stability with large capacitive loads - making it uniquely suited for dual-channel, ±5V, high-fidelity sensor signal conditioning where power, noise, and layout simplicity are jointly constrained.

Availability

MAX412CSA+ is available at Aetrix Electronics and suitable for low-noise instrumentation, infrared detection, frequency synthesizer filtering, and high-fidelity audio amplification requiring stable component supply across industrial and test equipment lifecycles.

Supply support for MAX412CSA+ 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

Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MAX412CSA+ belongs to Maxim's precision op amp product line, designed specifically for applications demanding ultra-low noise, wide bandwidth, and robust DC accuracy in space- and power-constrained systems.

FAQ

What is the maximum capacitive load the MAX412CSA+ can drive stably in unity-gain configuration?

The MAX412CSA+ remains unity-gain stable when driving capacitive loads up to 3900pF, as verified in the Typical Operating Characteristics section of the datasheet. This eliminates the need for external isolation resistors in most sensor buffering and filter applications. For loads exceeding 3900pF, a series output resistor (e.g., 10Ω) is recommended to restore phase margin. The MAX412CSA+'s internal compensation is optimized for this behavior without requiring external components under standard conditions.

Does the MAX412CSA+ support single-supply operation, and what is the minimum total supply voltage?

Yes, the MAX412CSA+ supports single-supply operation with a minimum total supply voltage of 4.8V (e.g., 0V to +4.8V). Its specified operating range extends from ±2.4V to ±5V, meaning it functions correctly with asymmetric supplies such as +5V and −2.4V. The input common-mode range is V− + 1.5V to V+ − 1.5V, and output swing is typically ±3.6V into 2kΩ from ±5V - all guaranteed across the 0°C to +70°C temperature range for the MAX412CSA+.

What is the guaranteed input offset voltage specification for the MAX412CSA+ over temperature?

The MAX412CSA+ has a guaranteed maximum input offset voltage of ±250µV over the 0°C to +70°C operating temperature range. Its offset voltage tempco is ±1µV/°C, meaning worst-case drift across the full range adds ±70µV. This ensures predictable calibration requirements in production test and long-term stability in precision measurement systems using the MAX412CSA+.

How does the MAX412CSA+ achieve its low 2.4nV/√Hz noise without compromising input protection?

The MAX412CSA+ achieves its 2.4nV/√Hz noise floor by omitting input current-limiting resistors - which would increase thermal noise - and instead uses back-to-back clamp diodes for ±0.1V differential input protection. This design preserves low-noise performance while providing basic ESD and overvoltage safeguarding. For applications requiring protection beyond ±0.1V, external series resistors (to limit input current to <20mA) must be added - a deliberate trade-off documented in the Applications Information section of the MAX412CSA+ datasheet.

Is the MAX412CSA+ pin-compatible with other dual op amps in SO-8 packages, such as the OP27 or AD822?

No, the MAX412CSA+ is not pin-compatible with OP27 or AD822. It follows the industry-standard dual op-amp SO-8 pinout (OUT1, IN1−, IN1+, V−, IN2+, IN2−, OUT2, V+), whereas OP27 is a single op-amp in 8-pin DIP/SO and AD822 uses a different pin assignment (e.g., V− on Pin 4, V+ on Pin 8, but IN1− on Pin 2 and IN1+ on Pin 3 - same as MAX412CSA+ - however OUT1 is on Pin 1 and OUT2 on Pin 7, matching MAX412CSA+). While the pinout matches AD822, electrical characteristics (noise, bandwidth, supply range) differ significantly - substitution requires full circuit validation. The MAX412CSA+ pinout is confirmed in the "Pin Configurations" diagram on page 1 of the datasheet.