Analog Devices Inc./Maxim Integrated MAX9920ASA/V+T

Overview

The MAX9920ASA/V+T from Maxim Integrated is a single-supply, AEC-Q100 qualified, high-accuracy current-sense amplifier optimized for automotive inductive load monitoring. It features a -20V to +75V input common-mode range, adjustable gain via external resistors (minimum 7.5V/V), ±200mV full-scale sense voltage capability, and rail-to-rail output. It enables precision bidirectional current sensing in H-bridge motor control and solenoid drive circuits where inductive kickback causes negative common-mode transients.

For engineers reviewing the MAX9920ASA/V+T datasheet, MAX9920ASA/V+T pinout, MAX9920ASA/V+T application, or MAX9920ASA/V+T equivalent, this device is selected when ±100mV bidirectional sensing range, 230kHz bandwidth, 400µV max input offset, 0.6% max gain error, and automotive-grade reliability across -40°C to +125°C are required.

Technical Context

The MAX9920 employs dual-level-shifting input architecture to support operation from -20V to +75V common-mode voltage, with one stage active above +2V and another below to handle negative kickback. Its internal instrumentation amplifier provides high CMRR (86dB over full range) and low offset drift (±2.4µV/°C at VCM = +14V).

Gain is set externally via FB pin using R1/R2 network, with attenuation factor of 4 applied at input stage-enabling ±200mV differential input for ±100mV bidirectional operation. Reference input (REFIN) accepts 0V to (VCC – 2.4V), typically VCC/2, to establish bidirectional zero-current output point.

Key Specifications

Pinout & Package

Package: 8-pin SOIC with exposed pad (SO-EP), RoHS-compliant and automotive qualified (+/V suffix). Thermal resistance θJA = 41°C/W (4-layer board), requiring exposed pad soldered to solid ground plane for thermal and electrical performance.

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 MAX9920ASA/V+T uniquely combines AEC-Q100 Grade 0 qualification, ±100mV bidirectional sensing, and externally adjustable gain in an automotive-qualified SO-EP package - making it the only option for calibrated, field-reprogrammable current monitoring in safety-critical vehicle subsystems.

Availability

MAX9920ASA/V+T is available at Aetrix Electronics and suitable for automotive motor control, solenoid actuation, and 48V battery management systems requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for MAX9920ASA/V+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, emphasizing high reliability and signal integrity.

The MAX9918/MAX9919/MAX9920 product line delivers high-common-mode, wide-temperature current-sense amplifiers specifically engineered for automotive inductive load monitoring where reverse battery, load dump, and inductive kickback are routine operating conditions.

FAQ

What is the maximum differential input voltage the MAX9920ASA/V+T can handle?

The MAX9920ASA/V+T supports a continuous differential input voltage (V_RS+ – V_RS–) of ±5V. This is explicitly specified in the Absolute Maximum Ratings table and distinguishes it from the MAX9918/MAX9919 (±15V). Exceeding ±5V may cause permanent damage or parametric shift. The ±200mV full-scale sense voltage is the recommended operating range-not the absolute limit-and is designed to maintain accuracy within ±1.7% gain error and ±3.5µV offset over temperature.

How does the MAX9920ASA/V+T achieve bidirectional current sensing?

The MAX9920ASA/V+T achieves bidirectional current sensing by applying a stable reference voltage-typically V_CC/2-to the REFIN pin. When current flows in one direction, V_OUT rises above REFIN; when reversed, V_OUT falls below REFIN. The internal attenuation stage scales ±200mV input to ±100mV differential output swing relative to REFIN. This architecture enables true zero-centered measurement without external op-amps or level shifters, and is validated across –40°C to +125°C with 75–90dB REFIN CMRR.

Can the MAX9920ASA/V+T be used in high-side current sensing configurations?

Yes, the MAX9920ASA/V+T is expressly designed for high-side current sensing, with its –20V to +75V input common-mode range supporting direct connection between battery positive and load. In such configurations, RS+ connects to battery, RS– to load, and the amplifier rejects common-mode transients like load dump (ISO 7637-2 Pulse 5a) and reverse battery. Its dual-level-shifting input ensures accurate sensing even when V_CM drops below 0V due to inductive kickback-verified in Typical Operating Characteristics plots (toc35, toc36).

What is the minimum gain achievable with the MAX9920ASA/V+T's external resistor network?

The minimum gain for the MAX9920ASA/V+T is 7.5V/V, guaranteed across temperature and process variation. This is defined by internal frequency compensation and confirmed in the Electrical Characteristics table under "Minimum Adjustable Gain". To achieve this, R2/R1 must equal 20 (since G = [1 + (R2/R1)]/4 → 7.5 = [1 + R2/R1]/4 → R2/R1 = 29). Using R1 = 1kΩ and R2 = 20kΩ yields G ≈ 5.25V/V but violates stability; actual design must follow the 7.5V/V floor and use R2/R1 ≥ 29 per datasheet Equation 2.

Is the exposed pad (EP) of the MAX9920ASA/V+T required to be connected to ground?

Yes, the exposed pad (EP) of the MAX9920ASA/V+T must be soldered to a large-area contiguous ground plane. The datasheet explicitly states: "CONNECT EP TO SOLID GROUND FOR PROPER THERMAL AND ELECTRICAL PERFORMANCE" and warns "Do not use as the only ground connection for the part." Failure to connect EP results in degraded thermal resistance (θ_JA increases from 41°C/W to 52°C/W), elevated junction temperature, and potential gain/offset drift beyond specification-especially critical in +125°C automotive environments where 1.5mA supply current generates >75mW dissipation.