Analog Devices Inc./Maxim Integrated MAX44242AKA+T

Overview

The MAX44242AKA+T from Analog Devices is a dual, rail-to-rail output operational amplifier optimized for high-impedance sensor interfacing, featuring 0.5pA (max) input bias current, 5nV/√Hz input voltage noise, and 10MHz gain-bandwidth product. It operates from a single 2.7V to 20V supply or ±1.35V to ±10V split supplies, consumes 1.2mA per channel, and is rated for -40°C to +125°C automotive operation in an 8-pin SOT23 package.

For engineers reviewing the MAX44242AKA+T datasheet, MAX44242AKA+T pinout, MAX44242AKA+T application, or MAX44242AKA+T equivalent, key selection criteria include ultra-low input bias current for photodiode transimpedance stages, low-noise performance in precision instrumentation, EMI-filtered inputs for noisy environments, and stable capacitive load drive up to 200pF without external compensation.

Technical Context

The MAX44242AKA+T employs a BiCMOS input stage enabling sub-picoampere input bias current across its full -40°C to +125°C operating range, critical for pH sensors and photodiode current-to-voltage conversion. Its integrated EMI filter suppresses RF interference at 400–2400MHz, with rejection ratios from 35dB to 57dB.

This unity-gain stable amplifier delivers 8V/µs slew rate and maintains phase margin ≥60° with 20pF load, supporting fast settling (1µs to 0.01%) and clean signal conditioning in medical pulse oximetry and industrial process control loops where DC accuracy and AC fidelity are both required.

Key Specifications

Pinout & Package

MAX44242AKA+T is housed in an 8-pin SOT23 package (JEDEC MO-178AA), with 0.65mm pitch, 2.9mm × 1.6mm footprint, and thermal resistance θ_JA = 196°C/W. Pin 4 (VSS) serves as the negative supply reference or ground in single-supply configurations.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual, low-input-bias-current op-amp applications.

Compared with LTC6078IS8#PBF and OPA2189IDR, the MAX44242AKA+T uniquely balances 10MHz bandwidth, 0.5pA bias current, and on-chip EMI filtering-making it the only option among the three qualified for automotive-grade photodiode interfaces where RF immunity and AC fidelity are co-required.

Availability

MAX44242AKA+T is available at Aetrix Electronics and suitable for chemical sensor interfaces, photodiode-based medical devices, industrial process controllers, precision instrumentation, and automotive subsystems requiring stable component supply across extended temperature ranges.

Supply support for MAX44242AKA+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

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.

The MAX44242AKA+T belongs to Analog Devices' precision amplifier portfolio, engineered specifically for high-impedance, low-noise sensor signal conditioning in harsh environments where reliability, EMI resilience, and DC accuracy are non-negotiable.

FAQ

What is the maximum capacitive load the MAX44242AKA+T can drive without oscillation?

The MAX44242AKA+T is specified to drive up to 200pF capacitive load without external isolation resistor compensation while maintaining stability (no sustained oscillation). This capability is verified across the full -40°C to +125°C temperature range and applies to both channels independently. For loads exceeding 200pF, a series isolation resistor (typically 10Ω–100Ω) at the output is recommended to preserve phase margin. The MAX44242AKA+T's internal compensation network enables this robust capacitive drive without sacrificing bandwidth or settling time.

Does the MAX44242AKA+T support true rail-to-rail input common-mode range?

No, the MAX44242AKA+T features rail-to-rail *output* swing but not rail-to-rail *input*. Its input common-mode voltage range is specified from VSS − 0.05V to VDD − 1.5V. This means the device cannot accept input signals within 1.5V of the positive rail (VDD) or 50mV below the negative rail (VSS). For applications requiring full rail-to-rail input, such as direct sensing of battery voltage down to 0V, an alternative amplifier with extended input range would be necessary. The MAX44242AKA+T's input range is intentionally optimized for high-impedance sensor buffering where common-mode levels are typically mid-supply.

How does the integrated EMI filter in the MAX44242AKA+T improve system-level robustness?

The MAX44242AKA+T integrates passive on-die EMI filters at both inputs, providing frequency-selective attenuation of RF interference. It achieves 57dB rejection at 2.4GHz, 50dB at 1.8GHz, and 40dB at 900MHz-critical for medical devices operating near WiFi/Bluetooth bands or industrial equipment near switch-mode power supplies. Unlike external RC filters that degrade bandwidth and add board space, this monolithic filter preserves the amplifier's 10MHz GBW and 8V/µs slew rate while eliminating RF rectification artifacts that cause baseline wander or false triggers. This makes the MAX44242AKA+T especially valuable in unshielded pulse oximeter probes or handheld gas analyzers.

What is the typical input offset voltage drift of the MAX44242AKA+T over temperature?

The MAX44242AKA+T has a guaranteed input offset voltage drift of 0.25µV/°C to 2.5µV/°C (typical 0.25µV/°C), as specified in the datasheet Note 3 and confirmed by design. This low drift ensures minimal output error accumulation across the full -40°C to +125°C operating range-critical for DC-coupled sensor interfaces like pH meters or strain gauge bridges where calibration intervals are long. At 100°C temperature change, typical drift contributes only 25µV of additional offset, far less than the 800µV max total VOS over temperature. This performance stems from its BiCMOS process and laser-trimmed input stage, making the MAX44242AKA+T suitable for high-stability industrial instrumentation.

Can the MAX44242AKA+T be used with a single 3.3V supply in low-power portable devices?

Yes, the MAX44242AKA+T is fully specified for single-supply operation from 2.7V to 20V, including 3.3V. At VDD = 3.3V and TA = +25°C, it draws only 1.2mA per channel (2.4mA total), delivering rail-to-rail output swing (within 25mV of each rail) and maintaining 10MHz GBW. Its input common-mode range extends to VSS − 0.05V (ground) and VDD − 1.5V (1.8V), accommodating typical 3.3V sensor outputs. This makes the MAX44242AKA+T ideal for battery-powered gas detectors, wearable biosensors, and handheld test equipment where low voltage, low power, and precision are simultaneously required.