Analog Devices Inc./Maxim Integrated MAX4173FESA

Overview

MAX4173FESA from Maxim Integrated is a precision high-side current-sense amplifier with fixed 50V/V gain, operating from +3V to +28V supply, delivering ±0.5% full-scale accuracy and 1.4MHz bandwidth in an 8-pin SO package. It enables accurate battery current monitoring in notebook computers and smart chargers without disrupting ground paths.

For engineers reviewing the MAX4173FESA datasheet, MAX4173FESA pinout, MAX4173FESA application, or MAX4173FESA equivalent, this page provides verified specifications, SO-package terminal mapping, real-world use cases in battery-powered systems, and validated alternative parts for current-sense amplifier selection.

Technical Context

The MAX4173FESA implements a high-impedance current-mirror-based sensing architecture that maintains 0V to +28V input common-mode range independent of VCC. Its output voltage is directly proportional to (I_LOAD × R_SENSE) × 50, eliminating external gain-setting resistors.

It features internal biasing that ensures functional operation down to 0V common-mode voltage - critical for deep-discharge battery monitoring - and delivers 420µA supply current across –40°C to +85°C while maintaining ±3mV input offset voltage and 12kΩ output impedance.

Key Specifications

Pinout & Package

MAX4173FESA is housed in an 8-pin SO (Small Outline) package with exposed pad option not specified; footprint matches standard 8SO outline 21-0041.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-side current-sense amplifier applications.

Compared with INA219BIDR and LT6106HS5#TRMPBF, MAX4173FESA uniquely combines 50V/V gain, 0V–28V common-mode operation, and 8SO package with explicit RS+/RS− terminals - making it optimal for analog-intensive, wide-input-voltage battery monitoring where ADC-free signal conditioning is required.

Availability

MAX4173FESA is available at Aetrix Electronics and suitable for notebook computers, smart battery chargers, and portable medical devices requiring stable component supply and long-term industrial availability.

Supply support for MAX4173FESA 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 is a U.S.-based semiconductor company specializing in analog and mixed-signal ICs for power, sensing, and communication applications.

The MAX4173 family was designed specifically for high-accuracy, high-side current sensing in space-constrained, battery-powered systems - emphasizing supply independence, low quiescent current, and robust common-mode performance.

FAQ

What is the gain setting of MAX4173FESA and how is it implemented?

The MAX4173FESA has a fixed gain of 50V/V, achieved through internal laser-trimmed resistor ratios and current-mirror topology - no external components are needed. This gain is factory-set and cannot be adjusted. The 'F' suffix explicitly denotes the 50V/V variant, distinguishing it from the T (20V/V) and H (100V/V) versions. Gain accuracy is guaranteed at ±0.5% over temperature, ensuring consistent scaling between sense voltage and output voltage across the full operating range of MAX4173FESA.

Does MAX4173FESA support operation with a 0V common-mode input voltage?

Yes, MAX4173FESA is fully functional at 0V common-mode input voltage - a key feature confirmed in its Absolute Maximum Ratings and Electrical Characteristics tables. This capability enables reliable current monitoring during deep battery discharge states where terminal voltage drops below 1V. Unlike many competitors, MAX4173FESA maintains specified accuracy and output behavior down to 0V without phase reversal or latch-up, as noted in the datasheet's Note 7.

What package type and pin count does MAX4173FESA use?

MAX4173FESA uses an 8-pin SO (Small Outline) package, as indicated by the 'ESA' suffix in the part number and confirmed in the Ordering Information table. It is not the SOT23-6 variant (which carries 'EUT' suffix). The 8SO package provides dedicated RS+, RS−, VCC, GND, and OUT pins plus three no-connect (N.C.) terminals - enabling robust Kelvin sensing and noise-immune layout in high-density applications.

Can MAX4173FESA be used with supply voltages below 3V?

No, MAX4173FESA is not rated for operation below +3V supply voltage. Its Absolute Maximum Ratings and Electrical Characteristics specify a guaranteed operating range of +3V to +28V. Attempting to power MAX4173FESA at 2.8V or lower may result in undefined behavior, reduced common-mode range, or failure to meet the ±0.5% full-scale accuracy specification. For sub-3V systems, alternative current-sense amplifiers with rail-to-rail input/output and lower V_CC minima should be evaluated instead of MAX4173FESA.

What is the output impedance of MAX4173FESA and how does it affect system design?

MAX4173FESA has a nominal output impedance of 12kΩ, as specified in the Electrical Characteristics table. This high impedance means the output behaves like a current source, and connecting loads <100kΩ will cause measurable gain compression - for example, a 100kΩ load introduces ~11% error. To preserve accuracy, MAX4173FESA output must drive high-impedance inputs (e.g., SAR ADCs with ≥1MΩ input resistance) or be buffered with a unity-gain op-amp having rail-to-rail input/output and supply ≥V_CC. This design constraint is inherent to MAX4173FESA's internal architecture.