The LM339 is a quad voltage comparator integrated circuit produced by Texas Instruments (TI). A comparator is a type of circuit that compares two input voltages and outputs a digital signal indicating which is larger. The LM339 is a type of comparator that is designed to operate from a single power supply voltage, typically 5V.
The LM339 has four independent comparators inside a single package, each with its own inputs, output and open-collector output. It also features a wide input common-mode voltage range of 0V to Vcc-1.5V, which allows it to compare input voltage that is common to both inputs, and it can handle input voltage range of -0.3V to Vcc+0.3V.
It is commonly used in a wide range of applications such as voltage monitoring, sensor signal processing, and other circuits that require precise voltage level detection. It is also widely used in automotive, industrial and consumer applications such as over-voltage protection, temperature sensing, and other circuits that require precise voltage level detection. Due to its low power consumption and high input impedance, it is also commonly used in battery-powered devices.