Voltage Comparators — LM393, LM339, LM311 ICs

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Voltage Comparator ICs — LM393, LM339, LM311 & More Voltage comparators are dedicated ICs designed for one purpose: comparing two analog voltages and producing a clean digital output. Unlike op-amps used as comparators, dedicated comparator ICs have open-collector outputs optimized for fast switching, direct TTL/CMOS interface, and wired-OR bus connections. This collection covers the most widely used comparator ICs for sensor threshold detection, zero-crossing detection, window comparators, and analog-to-digital signal conversion. Available Comparator ICs LM393 (Dual): 2 comparators, open-collector, 2V–36V single supply, 1.3μs response — the most popular dual comparator for sensor alarms and threshold detection LM339 (Quad): 4 comparators, open-collector, 2V–36V — four channels in one DIP-14 package for multi-channel monitoring LM311 (Single): Single high-speed comparator, strobe input, faster than LM393 — for high-speed threshold detection and zero-crossing LM2903 (Dual): Industrial-grade LM393 equivalent, −40°C to +125°C — for automotive and industrial applications Comparator vs Op-Amp — Why Use a Dedicated Comparator? Open-collector output: Directly drives LEDs, relays, and TTL/CMOS logic without additional circuitry Faster response: Optimized for switching, not linear amplification — no phase compensation capacitor Wired-OR: Multiple comparator outputs can share a single pull-up resistor for OR logic Wide supply range: 2V–36V single supply — works from a 3V coin cell to a 24V industrial supply Typical Applications Sensor threshold detection: Temperature, light, and pressure sensor alarm circuits Zero-crossing detection: AC waveform zero-crossing for phase control and power electronics Window comparator: Detect if a signal is within a defined voltage window Battery monitor: Low-battery detection and alert circuits Schmitt trigger: Add hysteresis with positive feedback for noise-immune switching Arduino analog input: External comparator for faster response tha