Analog Devices Inc./Maxim Integrated MAX412BCSA+

Overview

MAX412BCSA+ 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 consuming only 2.5mA per amplifier from ±2.4V to ±5V supplies. It is used in ultra-low-noise instrumentation amplifiers and infrared detector front-ends.

For engineers reviewing the MAX412BCSA+ datasheet, MAX412BCSA+ pinout, MAX412BCSA+ application, or MAX412BCSA+ equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, and two confirmed alternative parts with documented functional and application differences.

Technical Context

The MAX412BCSA+ employs a bipolar input stage engineered for optimal noise–accuracy–stability trade-off: low voltage noise requires high input-stage collector current, but that increases current noise and bias current-so feedback and source resistances must be minimized for best total noise performance. Its architecture supports stable unity-gain operation with capacitive loads up to 3900pF in voltage-follower configurations.

It operates across ±2.4V to ±5V supplies, delivering 7.3V_P-P output swing into 2kΩ, and maintains ≥115dB open-loop gain and ≥115dB CMRR at ±3.5V common-mode voltage. Input protection uses back-to-back clamp diodes without series current-limiting resistors-preserving low-noise integrity but requiring external current limiting for differential inputs >±1.0V.

Key Specifications

Pinout & Package

MAX412BCSA+ is housed in an 8-pin SO (Small Outline) package with industry-standard dual op-amp pinout. The exposed pad variant is not used in this part; thermal dissipation is managed via standard SO footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA211AIDR and AD8620ARZ-REEL7, the MAX412BCSA+ uniquely balances 2.4nV/√Hz noise, 28MHz bandwidth, and ±5V operation in an SO-8 package-making it optimal for space-constrained, low-voltage, wideband instrumentation where voltage noise dominates system noise floor.

Availability

MAX412BCSA+ is available at Aetrix Electronics and suitable for low-noise frequency synthesizers, infrared detector front-ends, high-quality audio preamplifiers, bridge signal conditioning circuits, and ultra-low-noise instrumentation amplifiers requiring stable component supply across industrial temperature ranges.

Supply support for MAX412BCSA+ 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 computing applications.

The MAX412BCSA+ belongs to Maxim's precision op amp product line, designed specifically for applications demanding ultra-low voltage noise, wide bandwidth, and low-voltage operation in measurement and signal-conditioning systems.

FAQ

What is the maximum capacitive load the MAX412BCSA+ can drive stably in unity-gain configuration?

The MAX412BCSA+ remains stable driving up to 3900pF in unity-gain voltage-follower configurations, as verified in the Typical Operating Characteristics (Figure 6b). For loads exceeding this value, an output isolation resistor (e.g., 10Ω) must be added between the amplifier output and the capacitance to restore phase margin and prevent oscillation-this is explicitly documented in the Applications Information section.

Does the MAX412BCSA+ require external input protection diodes?

Yes-the MAX412BCSA+ contains only back-to-back clamp diodes with no series current-limiting resistors, so differential input voltages exceeding ±1.0V require external current-limiting resistors to restrict input current to <20mA. This design preserves low-noise performance but shifts protection responsibility to the system designer, as stated in Note 1 of the Absolute Maximum Ratings table.

What is the guaranteed input offset voltage specification for MAX412BCSA+ over temperature?

The MAX412BCSA+ guarantees ±250µV maximum input offset voltage at +25°C (Electrical Characteristics, first table), and ±400µV maximum over the full −40°C to +85°C operating range (Electrical Characteristics, third table). Its offset voltage tempco is ±1µV/°C, meaning drift contributes ≤125µV over an 85°C span-well within the ±400µV limit.

Can MAX412BCSA+ operate from a single +5V supply?

No-MAX412BCSA+ is specified for dual-supply operation from ±2.4V to ±5V. While the datasheet notes capability for "single-supply operation with voltages as low as 4.8V", this refers to total supply voltage (V+ − V−), not single-ended rail. True single-supply use (e.g., V− = 0V, V+ = 5V) violates the common-mode input voltage range (V− −0.3V to V+ +0.3V) and output swing specifications, which assume symmetric rails.

How does the noise performance of MAX412BCSA+ vary with source resistance?

MAX412BCSA+ achieves minimum total input-referred noise with equivalent source resistances <10kΩ. Below 200Ω, voltage noise dominates; between 200Ω–3kΩ, thermal (resistor) noise dominates; above 3kΩ at 1kHz, current noise becomes dominant. This behavior is quantified in the "Total Noise Density vs. Matched Source Resistance" plot (Figure 15) and explained in the Applications Information section.