STMicroelectronics LM393ADT

Overview

LM393ADT from STMicroelectronics is a dual low-voltage comparator IC designed for single-supply operation from 2 V to 36 V (or ±1 V to ±18 V), featuring ±1 mV typical input offset voltage, 20 nA typical input bias current, and 0.45 mA supply current per comparator. It supports TTL/CMOS/MOS/DTL/ECL logic interfaces and is widely used in voltage monitoring, zero-crossing detection, and level-shifting circuits in industrial power supplies and sensor signal conditioning.

For engineers reviewing the LM393ADT datasheet, LM393ADT pinout, LM393ADT application, or LM393ADT equivalent, key selection considerations include its rail-to-rail input common-mode range (including ground), 80 mV typical output saturation voltage at 4 mA sink, and compatibility with SO8 packaging for legacy PCB designs requiring mechanical and thermal reliability.

Technical Context

The LM393ADT implements two independent open-collector comparators with PNP input stages, enabling input voltages down to ground on single-supply operation while maintaining stable biasing across temperature. Its differential input voltage range equals the full supply voltage (±36 V), supporting overvoltage-tolerant sensing without clamping diodes.

Internal architecture delivers 50–200 V/mV large-signal voltage gain and sub-μs response time (1.3 μs typical at 100 mV step, 300 ns at larger overdrive), optimized for low-power threshold detection rather than linear amplification. Output stage is compatible with 5 V TTL and 3.3 V CMOS loads via external pull-up.

Key Specifications

Pinout & Package

LM393ADT is supplied in SO8 package (standard small-outline integrated circuit, 150 mil width, 1.27 mm lead pitch), with exposed pad not present - distinct from DFN8 or MiniSO8 variants. Pin functions are electrically identical across all package options.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM393DR, LM393ADT offers tighter temperature-limited offset (±1 mV typ. at 25°C, validated over 0–70°C) and ST's qualified SO8 manufacturing; TL331IDBVR trades channel count and speed for extreme quiescent current reduction, making it unsuitable for direct replacement in dual-comparator designs.

Availability

LM393ADT is available at Aetrix Electronics and suitable for voltage monitoring systems, zero-crossing detection circuits, transducer signal conditioning, and level-shifting interfaces requiring stable component supply and long-term industrial availability.

Supply support for LM393ADT 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, specializing in automotive, industrial, and power management ICs with vertical manufacturing and broad portfolio coverage.

The LM393 series belongs to ST's precision analog comparators product line, engineered for robust performance in cost-sensitive industrial and consumer applications where reliability, wide supply range, and ground-sensing capability are essential.

FAQ

Can LM393ADT operate from a 3.3 V supply?

Yes - LM393ADT supports single-supply operation from 2 V to 36 V, including 3.3 V. At 3.3 V, input common-mode range extends from 0 V to 1.8 V, and output saturation remains below 100 mV at 4 mA sink. Logic compatibility with 3.3 V MCUs is maintained via external pull-up to 3.3 V.

Does LM393ADT require external hysteresis?

LM393ADT has no internal hysteresis; external positive feedback (e.g., resistor from OUT to IN+) is required to prevent oscillation when input signals transition slowly near the threshold. Typical hysteresis values range from 10 mV to 50 mV depending on noise amplitude and comparator gain.

What is the maximum sink current for LM393ADT outputs?

The absolute maximum sink current is not specified, but electrical characteristics show 6–18 mA output sink capability at Vo = 1.5 V with Vid = 1 V. For reliable long-term operation, ST recommends limiting continuous sink current to ≤10 mA per output to maintain VOL < 150 mV and avoid thermal stress in SO8 package.

Is LM393ADT pin-compatible with LM339?

No - LM339 is a quad comparator in 14-pin SOIC/N packages; LM393ADT is dual in 8-pin SO8. While both share similar electrical specs (Vio, ICC, open-collector outputs), pin mapping differs completely: LM393ADT uses pins 1/7 for outputs and 2/3/5/6 for inputs; LM339 allocates outputs to pins 1/2/13/14 and inputs across remaining pins. PCB layout is not interchangeable.