Analog Devices Inc./Maxim Integrated MAX4209HAUA+T

Overview

The MAX4209HAUA+T from Maxim Integrated is a fixed-gain (100V/V), ultra-low offset and drift instrumentation amplifier in an 8-pin μMAX package, featuring ±20μV max input offset voltage, 0.2μV/°C max offset drift, 750kHz gain-bandwidth product, rail-to-rail output, and buffered REFIN/MODE for precision bipolar operation in single-supply systems - ideal for strain-gauge signal conditioning in automotive sensor modules.

For engineers reviewing the MAX4209HAUA+T datasheet, MAX4209HAUA+T pinout, MAX4209HAUA+T application, or MAX4209HAUA+T equivalent, key selection criteria include its guaranteed ±0.25% max gain error over -40°C to +125°C, 1pA CMOS input bias current enabling ground-sensing, and integrated REF buffer eliminating loading errors when using resistive dividers or ADC references.

Technical Context

The MAX4209HAUA+T employs a spread-spectrum autozeroing architecture that continuously measures and corrects input offset, eliminating 1/f noise and drift over time and temperature. Its transconductance-based core enables true ground-sensing capability while maintaining high common-mode rejection (90dB min over full temperature range).

This device uses a factory-laser-trimmed internal resistor network to fix gain at 100V/V with ±0.03% typical accuracy. The buffered REFIN/MODE pin operates as a triple-function terminal: reference input (when biased between VSS+0.2V and VDD−1.3V), shutdown enable (at VDD), or high-impedance disable (at VSS), directly controlling internal REF buffer state and supply current (750μA active, 1.4μA shutdown).

Key Specifications

Pinout & Package

The MAX4209HAUA+T is housed in an 8-pin μMAX package (3mm × 3mm, 0.8mm height), optimized for space-constrained automotive and portable medical PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar instrumentation amplifier applications.

Compared with INA128UA and AD8429ARZ, the MAX4209HAUA+T uniquely combines fixed 100V/V gain with integrated REF buffering, automotive temperature rating, and sub-2μA shutdown - making it optimal for compact, low-power, ground-sensing sensor interfaces where layout area and long-term calibration stability are critical.

Availability

The MAX4209HAUA+T is available at Aetrix Electronics and suitable for strain-gauge amplification, precision low-side current sensing, and battery-powered medical equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX4209HAUA+T 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, designs precision analog, mixed-signal, and power management ICs for demanding industrial, automotive, and medical applications.

The MAX4209HAUA+T belongs to the MAX4208/MAX4209 family of autozeroing instrumentation amplifiers engineered specifically for ultra-low-drift, ground-sensing signal conditioning in sensor front-ends where DC accuracy and long-term stability are non-negotiable.

FAQ

What is the maximum differential input voltage supported by the MAX4209HAUA+T?

The MAX4209HAUA+T supports a maximum differential input voltage of ±100mV. Exceeding this range degrades linearity and gain accuracy, as confirmed in the Electrical Characteristics table and Applications Information section. Operation beyond ±100mV may cause measurable nonlinearity (>700ppm) and increased gain error, especially at temperature extremes. For reliable 0.03% typical gain accuracy and <150ppm nonlinearity, the input must remain within this specified limit.

Does the MAX4209HAUA+T require external gain-setting resistors?

No, the MAX4209HAUA+T does not require external gain-setting resistors. It features a factory-laser-trimmed internal resistor network that fixes gain at 100V/V with ±0.03% typical accuracy. Unlike the adjustable-gain MAX4208, the MAX4209HAUA+T has FB internally connected to these precision resistors - simplifying layout, eliminating resistor matching concerns, and improving thermal tracking stability in the final design.

How does the REFIN/MODE pin function in shutdown mode for the MAX4209HAUA+T?

In shutdown mode, the REFIN/MODE pin of the MAX4209HAUA+T must be driven to VDD (typically 5V). This action disables the internal amplifier core and REF buffer, reducing supply current to 1.4μA (typ). The output enters high-impedance state, and REF is no longer buffered. Shutdown recovery time is 20ms, as specified in the Electrical Characteristics table. Driving REFIN/MODE to VDD is the only method to activate shutdown - no additional control logic or external circuitry is needed.

Can the MAX4209HAUA+T operate with a single 3.3V supply?

Yes, the MAX4209HAUA+T operates with a single 3.3V supply, as its specified supply range is 2.85V to 5.5V. At 3.3V, it maintains full functionality: rail-to-rail output swing (VSS + 40mV to VDD − 60mV), 750μA supply current (buffer off), and guaranteed performance across -40°C to +125°C. Output swing is reduced proportionally versus 5V operation, but the 7.5kHz small-signal bandwidth and ±20μV offset remain unchanged - making it suitable for compact 3.3V IoT sensor nodes.

What is the purpose of the CFB capacitor connection in the MAX4209HAUA+T?

The CFB capacitor connects from OUT to FB on the MAX4209HAUA+T to reduce autozero-related noise spikes, particularly in the 10Hz–1kHz band. Though FB is internally connected to gain resistors, the CFB path provides a low-impedance shunt for high-frequency noise generated by the spread-spectrum autozeroing clock. Typical values range from 1nF to 10nF; 1nF reduces noise by ~30% without compromising 0.1% settling time (120μs), as verified in the Typical Operating Characteristics plots.