Analog Devices Inc./Maxim Integrated MAX9919FASA+T

Overview

The MAX9919FASA+T from Maxim Integrated is a fixed-gain, high-accuracy current-sense amplifier optimized for automotive and industrial inductive load monitoring. It features a -20V to +75V input common-mode range, 45V/V fixed gain, 400µV max input offset voltage, and operates from a single 4.5V–5.5V supply across -40°C to +125°C. It enables precision unidirectional or bidirectional current sensing in H-bridge motor control and solenoid drivers where inductive kickback causes negative common-mode transients.

For engineers reviewing the MAX9919FASA+T datasheet, MAX9919FASA+T pinout, MAX9919FASA+T application, or MAX9919FASA+T equivalent, key selection criteria include its AEC-Q100 qualification, SO-EP package thermal performance (θ_JA = 41°C/W), rail-to-rail output swing, and support for ±100mV bidirectional sensing when REFIN = V_CC/2.

Technical Context

The MAX9919FASA+T employs dual-level-shifting input architecture to maintain accuracy across its full -20V to +75V common-mode range: one stage handles +2V to +75V, another handles -20V to +2V. Its laser-trimmed 45V/V gain eliminates external resistor networks, reducing layout sensitivity and drift.

It supports both unidirectional operation (REFIN = GND) and bidirectional operation (REFIN = V_CC/2), with output referenced to either ground or the reference input. The rail-to-rail output delivers 100mV headroom from each rail to ensure rated gain accuracy, and shutdown mode reduces supply current to ≤10µA.

Key Specifications

Pinout & Package

Package: 8-pin SOIC with exposed pad (SO-EP), RoHS-compliant, thermal resistance θ_JA = 41°C/W (4-layer board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA240A1QDRQ1 and MAX40056ATA+T, the MAX9919FASA+T offers optimal balance of gain (45V/V), common-mode range (-20V to +75V), and AEC-Q100 qualification for mid-range automotive motor control-requiring no signal conditioning or layout redesign when replacing legacy discrete solutions.

Availability

MAX9919FASA+T is available at Aetrix Electronics and suitable for H-bridge motor control, solenoid actuation, and automotive battery management requiring stable component supply across extended temperature and voltage ranges.

Supply support for MAX9919FASA+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 and mixed-signal ICs for automotive, industrial, and communications markets.

The MAX9918/MAX9919/MAX9920 product line delivers high-accuracy current sensing for safety-critical automotive subsystems-specifically engineered to replace discrete op-amp solutions in motor, solenoid, and battery monitoring applications.

FAQ

What is the maximum continuous differential input voltage for the MAX9919FASA+T?

The MAX9919FASA+T supports ±15V continuous differential input voltage (V_RS+ – V_RS-). This rating allows reliable operation with 50mV full-scale sense voltage across shunts in high-noise automotive environments without clipping or damage, provided common-mode voltage remains within -20V to +75V limits.

Does the MAX9919FASA+T require external gain-setting resistors?

No, the MAX9919FASA+T does not require external gain-setting resistors. It integrates laser-trimmed internal resistors to deliver a fixed 45V/V gain. Pin 6 (FB) must be left unconnected-connecting external components to FB may disrupt internal biasing and degrade accuracy.

How does the MAX9919FASA+T support bidirectional current sensing?

The MAX9919FASA+T supports bidirectional current sensing by setting REFIN (Pin 7) to V_CC/2. This establishes a mid-supply reference, causing the output (OUT) to swing symmetrically around V_CC/2-positive current yields V_OUT > V_CC/2, negative current yields V_OUT < V_CC/2-enabling accurate measurement of charge/discharge direction in battery systems.

Is the MAX9919FASA+T qualified for automotive applications?

Yes, the MAX9919FASA+T is AEC-Q100 Grade 1 qualified (as indicated by the "/V+" suffix in related variants). While the exact "FASA+T" marking denotes the RoHS-compliant SO-EP package, its die and characterization are identical to the AEC-Q100 qualified MAX9919FASA/V+, making it suitable for automotive under-hood use.

What thermal design considerations apply to the MAX9919FASA+T's exposed pad?

The exposed pad (EP) of the MAX9919FASA+T must be soldered to a large-area contiguous ground plane to achieve θ_JA = 41°C/W. It is not a substitute for Pin 4 (GND); both must be connected. Insufficient copper area or thermal vias increases junction temperature, risking gain drift and accelerated aging-especially at 1.2mA supply current in +125°C ambient.