STMicroelectronics LM339AD

Overview

LM339AD from STMicroelectronics is a low-power quad voltage comparator IC designed for precision threshold detection in single-supply systems. It features ±1 mV typical input offset voltage, 1.1 mA supply current, rail-to-rail input common-mode range including ground, and TTL/CMOS-compatible open-collector outputs - enabling direct interfacing with microcontrollers and logic circuits in industrial sensor monitoring applications.

For engineers reviewing the LM339AD datasheet, LM339AD pinout, LM339AD application, or LM339AD equivalent, key selection considerations include its ground-sensing capability on single supply, low quiescent current across 2–36 V operation, output sink strength up to 16 mA, and guaranteed performance over 0 °C to +70 °C ambient temperature.

Technical Context

The LM339AD uses PNP-input transistor pairs to achieve input common-mode voltage down to ground on single supply, eliminating need for level-shifting circuitry. Its open-collector outputs support wired-OR logic and flexible pull-up configurations across TTL, CMOS, ECL, and MOS families.

It operates with supply voltages from +2 V to +36 V (or ±1 V to ±18 V), supports differential input swings up to ±36 V, and delivers 1.3 μs typical response time with 100 mV input step and 5 mV overdrive - optimized for slow-to-moderate speed analog decision-making rather than high-frequency signal comparison.

Key Specifications

Pinout & Package

LM339AD is packaged in SO14 (plastic micropackage), a 14-pin small outline integrated circuit with 1.27 mm pitch, 8.55–8.75 mm body length, and 3.80–4.00 mm width - compliant with JEDEC MS-012 and RoHS requirements.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM339DR, LM339AD offers tighter offset tolerance and lower supply current but lacks automotive qualification; versus TL331IDBVR, it provides four independent channels in one SO14 package, reducing board area and interconnect complexity for multi-threshold systems.

Availability

LM339AD is available at Aetrix Electronics and suitable for industrial sensor interfaces, power supply supervision, and analog signal conditioning requiring stable component supply across long-lifecycle embedded programs.

Supply support for LM339AD 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The LM339 series belongs to ST's precision analog comparators product line, engineered specifically for robust, low-cost threshold detection in harsh environments where reliability and wide supply flexibility are essential.

FAQ

Can LM339AD operate from a 3.3 V supply?

Yes, LM339AD supports single-supply operation from +2 V to +36 V, including 3.3 V. At 3.3 V, input common-mode range is 0 V to 1.8 V, output saturation voltage remains ≤400 mV at 4 mA sink, and supply current is ~1.1 mA - verified per Table 3 in ST DocID2159 Rev 4.

Does LM339AD require external pull-up resistors on its outputs?

Yes, all four outputs are open-collector NPN transistors and require external pull-up resistors to define logic HIGH voltage. Typical values range from 1 kΩ (for 16 mA sink) to 10 kΩ (for low-current logic interfacing); pull-up to any voltage ≤36 V is permitted.

What is the maximum input voltage allowed at LM339AD pins?

The absolute maximum input voltage is −0.3 V to +36 V (Table 1). Inputs may safely exceed VCC by up to 36 V differential, but the common-mode voltage must stay within 0 V to (VCC − 1.5 V); negative excursions below −0.3 V risk damage.

Is LM339AD pin-compatible with LM239AD or LM139AD?

Yes - all three variants (LM139AD, LM239AD, LM339AD) share identical SO14 pinout, electrical interface, and functional block diagram. Differences lie only in specified operating temperature ranges (−55 to +125 °C, −40 to +105 °C, and 0 to +70 °C respectively) and tighter offset specs for 'A' grade parts.