Texas Instruments LM339AMX

Overview

LM339AMX from Texas Instruments is a quad open-collector voltage comparator IC designed for industrial and embedded signal conditioning. It features ±3 mV maximum input offset voltage, 0.8 mA supply current per comparator at 5 V, and operates from 2–36 V single or ±1–±18 V dual supply. Its input common-mode range includes ground, enabling direct sensing of near-zero-voltage signals in battery-powered and automotive subsystems.

For engineers reviewing the LM339AMX datasheet, LM339AMX pinout, LM339AMX application, or LM339AMX equivalent, this device supports TTL/CMOS interfacing, wired-OR logic configurations, and low-power analog-to-digital threshold detection across wide supply ranges - critical for precision level-shifting, window comparators, and multivibrator timing circuits.

Technical Context

The LM339AMX integrates four independent high-gain comparators with PNP input stages, enabling rail-to-rail input operation down to GND on single supply. Its uncommitted NPN output transistors support open-collector sinking up to 16 mA with 250 mV saturation voltage at 4 mA load - ideal for driving discrete logic families without level-shifting circuitry.

No internal antisaturation clamps are used, resulting in ultra-low 0.1 nA output leakage current in OFF state. The bias network delivers supply-independent current draw (0.8–2.5 mA total), and differential input voltage tolerance extends to ±36 V - exceeding supply rails without damage when inputs remain ≥ −0.3 V.

Key Specifications

Pinout & Package

LM339AMX is packaged in a 14-pin SOIC (Small Outline Integrated Circuit) with body size 8.65 mm × 3.91 mm, optimized for automated PCB assembly and space-constrained industrial controls.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM339MX and TLV3704IPW, LM339AMX delivers tighter offset voltage (±3 mV) and extended industrial temperature range (−40°C to +85°C) in a standard SOIC-14 package - making it optimal for cost-sensitive yet precision-critical industrial controls where drop-in replacement and legacy board compatibility are mandatory.

Availability

LM339AMX is available at Aetrix Electronics and suitable for industrial automation, battery management systems, and automotive body electronics requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LM339AMX 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

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in precision signal chain components.

The LM339AMX belongs to TI's legacy quad comparator product line, engineered for robust industrial signal conditioning - emphasizing wide supply flexibility, ground-sensing capability, and open-collector interoperability with legacy logic families.

FAQ

What is the maximum supply voltage rating for LM339AMX?

The LM339AMX supports a maximum supply voltage of 36 VDC in single-supply mode or ±18 VDC in dual-supply mode. Absolute maximum ratings specify 36 V across V+ and GND terminals; exceeding this may cause permanent damage. Operation at 36 V is validated per TI's SNOSBJ3E datasheet under recommended conditions, with thermal derating applied above 70°C ambient.

Does LM339AMX support rail-to-rail input operation?

The LM339AMX does not support true rail-to-rail input - its input common-mode voltage range extends from GND to V+−1.5 V at 25°C. This allows sensing down to 0 V (ground) on single supply, but the upper limit remains 1.5 V below V+. For example, at V+ = 5 V, inputs function correctly from 0 V to 3.5 V. Inputs beyond this range may cause phase reversal or undefined output states.

Can LM339AMX outputs be wired together for OR logic?

Yes, LM339AMX outputs can be directly wired together to implement wired-OR logic because all four outputs are open-collector NPN transistors. When any output sinks current, the shared node pulls LOW; only when all outputs are HIGH (OFF) does the external pull-up resistor establish a HIGH level. This configuration is explicitly supported in TI's datasheet Figure 16 and enables compact window comparator and alarm aggregation circuits.

What is the typical output saturation voltage of LM339AMX at 4 mA load?

The typical output saturation voltage of LM339AMX is 250 mV at 4 mA sink current, as specified in Section 6.5 of the SNOSBJ3E datasheet. This value ensures reliable recognition as a logic LOW by TTL and CMOS families - for instance, a 5 V system sees 250 mV as well within the 0.8 V maximum VIH threshold for standard 74HC logic. Maximum guaranteed value is 400 mV under worst-case conditions.

Is LM339AMX suitable for battery-powered applications?

Yes, LM339AMX is well-suited for battery-powered applications due to its 0.8 mA typical supply current at 5 V - translating to ~4 mW total power consumption for all four comparators. Its ability to operate down to 2 V supply enables use with single-cell Li-ion (2.7–4.2 V) or two-cell alkaline (2–3 V) batteries. Combined with ground-sensing inputs and low 25 nA bias current, it minimizes loading on high-impedance battery monitoring dividers.