Texas Instruments LM393AD

Overview

LM393AD from STMicroelectronics is a dual low-power voltage comparator IC designed for single-supply operation from +2V to +36V or split supplies ±1V to ±18V, featuring ±1mV typical input offset voltage, 25nA typical input bias current, and rail-to-rail input common-mode range including ground. It delivers TTL/CMOS-compatible open-collector outputs and is widely used in level detection, zero-crossing sensing, and analog threshold monitoring in industrial control and power management circuits.

For engineers reviewing the LM393AD datasheet, LM393AD pinout, LM393AD application, or LM393AD equivalent, key selection criteria include input offset voltage stability over temperature (0°C to +70°C), low quiescent supply current (0.4mA at +5V), output sink capability (6mA min), input common-mode range down to ground, and SO-8 package compatibility with standard PCB layouts.

Technical Context

The LM393AD integrates two independent comparators with PNP input stages enabling input voltages down to −0.3V relative to VCC− while maintaining functionality across full supply ranges. Its differential input voltage tolerance equals the supply voltage (±36V max), and internal biasing ensures stable operation without external compensation.

Output stage uses open-collector NPN transistors capable of sinking up to 16mA, compatible with TTL, DTL, ECL, MOS, and CMOS logic families. Response time is 1.3µs (100mV step, 5mV overdrive) and improves to 300ns under larger overdrive conditions, supporting moderate-speed threshold detection in sensor interfaces and power sequencing.

Key Specifications

Pinout & Package

LM393AD is supplied in an SO-8 (Plastic Micropackage) surface-mount package measuring 4.80–5.00 mm × 3.80–4.00 mm, with 1.27 mm lead pitch and gull-wing leads. Thermal resistance θ_JA is 175°C/W at +25°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM393AD, LM393DT offers identical functionality in tape-and-reel format for production lines, while TLV3702IDR trades wide-voltage robustness for nanoscale quiescent current-making it optimal for energy-constrained designs where supply rails are tightly regulated.

Availability

LM393AD is available at Aetrix Electronics and suitable for industrial control panels, automotive body electronics, and consumer appliance power management requiring stable component supply across extended temperature ranges (0°C to +70°C).

Supply support for LM393AD 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, delivering innovative silicon solutions for automotive, industrial, and consumer markets since 1987.

The LM393 series belongs to ST's legacy analog comparators product line, engineered specifically for cost-sensitive, high-reliability applications demanding wide supply range, ground-sensing capability, and logic-compatible outputs in industrial and embedded systems.

FAQ

What is the maximum differential input voltage the LM393AD can tolerate?

The LM393AD supports a differential input voltage range equal to the supply voltage, with an absolute maximum rating of ±36V. This means that if VCC+ = +30V and VCC− = 0V, the device tolerates up to +30V at one input and 0V at the other - a 30V differential - without damage, provided common-mode limits are respected.

Can the LM393AD operate with inputs below ground?

Yes - the LM393AD allows input voltages down to −0.3V relative to VCC− (ground in single-supply mode). This limited negative excursion supports small AC-coupled signals or transient spikes without clamping diodes, but sustained sub-ground operation requires external protection.

Does the LM393AD have internal hysteresis?

No - the LM393AD has no built-in hysteresis. External positive feedback (e.g., resistor from output to non-inverting input) must be added to implement hysteresis for noise immunity in threshold detection applications such as zero-crossing or level sensing.

What is the minimum recommended pull-up resistor value for the open-collector outputs?

For reliable TTL interfacing at VCC = +5V, a 1.6kΩ pull-up yields ~3.2V HIGH level with 4mA sink (per output spec). For CMOS loads or higher supply voltages, values up to 10kΩ are acceptable; lower values increase speed but raise static power - design must balance rise time, power, and logic threshold margins.