LM339J: Overview,Specifications,Main uses,Features,application fields,working principle and alternative models


LM339J Overview:

The LM339J is a quad voltage comparator integrated circuit that consists of four independent voltage comparators. It is widely used for comparing voltages and making decisions based on those comparisons in various electronic circuits. Here is an overview of the LM339J, including its specifications, main uses, features, application fields, working principle, and alternative models:



  • Manufacturer: Texas Instruments, ON Semiconductor, STMicroelectronics, etc.
  • IC Type: Quad Voltage Comparator
  • Package: DIP, SOIC, PDIP
  • Supply Voltage: Typically ±1.5V to ±18V
  • Input Offset Voltage: Typically 2 mV
  • Input Bias Current: Typically 25 nA
  • Response Time: Typically a few microseconds
  • Number of Channels: 4

Main Uses:

  • Voltage Comparison: Used to compare voltages from different sources.
  • Signal Conditioning: Employed in signal processing circuits.
  • Threshold Detection: Utilized for threshold detection and decision-making.
  • Waveform Detection: Detects specific waveform conditions in circuits.


  • Four Independent Comparators: Contains four separate voltage comparators in a single IC.
  • Open-Collector Outputs: Allows for versatile output connections.
  • Wide Supply Voltage Range: Can operate over a wide range of supply voltages.
  • Low Input Bias Current: Suitable for applications requiring minimal input current.
  • High Input Impedance: Facilitates easy interfacing with various circuit elements.

Application Fields:

  • Overvoltage Protection: Implementing overvoltage protection circuits.
  • Switching Circuits: Used in digital logic circuits and switching applications.
  • Motor Control: Employed for motor control systems for speed and position sensing.
  • Battery Management: Utilized in battery management circuits for voltage monitoring.

Working Principle:

  • The LM339J compares the voltages presented at its inputs and produces a corresponding output based on the comparison results.
  • Each comparator within the LM339J has a reference voltage level against which the input voltage is compared.
  • The output of the comparator changes state depending on whether the input voltage is higher or lower than the reference voltage.

Alternative Models:

  • LM311: Single voltage comparator with similar functionalities.
  • LM393: Dual voltage comparator IC providing two comparators.
  • LM324: Quad operational amplifier with general-purpose functionality.


  • The LM339J is a versatile voltage comparator IC commonly used in various applications requiring voltage comparison and decision-making based on voltage levels.
  • Ensure proper decoupling and signal conditioning when using the LM339J in circuit designs for optimal performance and reliability.

The LM339J quad voltage comparator is a useful component for a wide range of applications where voltage comparison and decision-making based on those comparisons are required. Its integrated design and multiple channels make it a valuable tool in many electronic circuits.