Analog Devices Inc./Maxim Integrated LMX331HAUK+T

Overview

LMX331HAUK+T from Maxim Integrated is a single-channel, low-voltage, open-drain comparator with internal 2mV hysteresis, designed for noise-immune threshold detection in automotive and portable systems. It operates from 1.8V to 5.5V, delivers 60µA supply current at 5V, achieves 90ns propagation delay (tPHL) at 100mV overdrive, and supports -40°C to +125°C operation - ideal for battery-monitoring circuits in automotive ECUs.

For engineers reviewing the LMX331HAUK+T datasheet, LMX331HAUK+T pinout, LMX331HAUK+T application, or LMX331HAUK+T equivalent, key selection criteria include guaranteed hysteresis, rail-to-rail input common-mode range including ground, low output saturation voltage (100mV @ 1mA), and SOT23-5 packaging for space-constrained PCB layouts.

Technical Context

The LMX331HAUK+T implements a CMOS-input, open-drain output architecture with internally fixed 2mV hysteresis - eliminating external feedback components while preventing chatter on slow or noisy inputs. Its input stage accepts common-mode voltages from -0.1V to VDD–0.7V, enabling direct ground-referenced sensing.

It features no phase reversal under overdriven conditions, 70dB PSRR at 1.8V, and maintains stable 90–100ns propagation delay across -40°C to +125°C. The device draws only 60µA per comparator at 5V, making it suitable for always-on monitoring nodes in low-power automotive subsystems.

Key Specifications

Pinout & Package

LMX331HAUK+T is housed in a 5-pin SOT23 package (2.9mm × 1.6mm × 1.1mm), optimized for high-density automotive PCBs and portable electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMX331HAUK+T, LMV331M5X/NOPB offers lower unit cost but increases design complexity and board area due to external hysteresis components, while TLV331IDBVR provides matching hysteresis functionality but mandates layout revision and sacrifices 60ns speed advantage in time-critical fault responses.

Availability

LMX331HAUK+T is available at Aetrix Electronics and suitable for automotive body control modules, portable medical devices, and USB-C power adapters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LMX331HAUK+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for automotive, industrial, and communications markets.

The LMX331HAUK+T belongs to Maxim's LMX331/LMX393/LMX339 family - engineered for low-voltage, high-reliability threshold detection in harsh environments where noise immunity, small footprint, and wide temperature operation are mandatory.

FAQ

What is the purpose of the internal 2mV hysteresis in the LMX331HAUK+T?

The internal 2mV hysteresis in the LMX331HAUK+T prevents output oscillation when input signals are slow-moving or contaminated with noise - such as in battery voltage monitoring or coolant level sensing. It establishes distinct upper and lower switching thresholds, ensuring clean, chatter-free transitions without requiring external feedback components. This feature is factory-trimmed and remains stable across -40°C to +125°C.

Can the LMX331HAUK+T operate from a 1.8V supply while maintaining full specification?

Yes, the LMX331HAUK+T is fully specified down to 1.8V supply voltage: it guarantees 5mV input offset voltage, 35mV output saturation voltage (at 1mA sink), and 500ns propagation delay (10mV overdrive) at 1.8V. Its input common-mode range extends to -0.1V, enabling direct interface with ground-referenced sensors even at minimum supply - critical for single-cell Li-ion systems.

Is the LMX331HAUK+T pin-compatible with the standard LMX331AUK+T?

Yes, the LMX331HAUK+T is pin-compatible with the LMX331AUK+T - both use identical 5-pin SOT23 packaging and share identical pinout (IN+, VSS, IN–, OUT, VDD). The sole functional difference is the inclusion of internal 2mV hysteresis in the "H" variant, which does not affect pin assignment, electrical interface, or PCB layout.

Does the LMX331HAUK+T require an external pull-up resistor on its output?

Yes, the LMX331HAUK+T features an open-drain output that requires an external pull-up resistor to VDD or another logic rail. Typical values range from 2.2kΩ to 10kΩ depending on rise-time and bus loading requirements. No internal pull-up is present - omitting the external resistor results in undefined or floating output states during high-impedance periods.

How does the LMX331HAUK+T compare to LMV331 in terms of temperature performance?

The LMX331HAUK+T is rated for -40°C to +125°C operation with guaranteed parameters across that full range, whereas the LMV331 is typically specified only from -40°C to +85°C. At +125°C, the LMX331HAUK+T maintains ≤9mV input offset voltage and ≤700mV output saturation voltage - making it suitable for under-hood automotive applications where the LMV331 would exceed its operational limits.