LM339 Datasheet – Quad Voltage Comparator ( PDF )

The LM339 is a quad voltage comparator IC.

Part Number: LM339

Function: Quad Voltage Comparator for Industrial, Commercial and Military Applications

Package: SOIC, DIP, 14 Pin type

Manufacturer: Intersil

Intersil Corporation was acquired by Renesas Electronics Corporation on February 24, 2017.

Image and Pinouts:

LM339 datasheet



The LM339 is Quad Voltage Comparator.

The devices in this series consist of four independent single or dual supply voltage comparators on a single monolithic substrate. The common mode input voltage range includes ground even when operated from a single supply, and the low power supply current drain makes these comparators suitable for battery operation. These types were designed to directly interface with TTL and CMOS.

Type CA139A, has a lower input offset voltage than the CA139. Some of the SOIC parts are available on tape and reel (see Ordering Information table). Replace the M suffix in
the part number with M96 when ordering (e.g.,CA0239M96).

Each comparator in the LM339 has two inputs, the non-inverting input (V+) and the inverting input (V-), and a single output. The output is an open collector transistor that can sink current when the output is in a low state. The output can be connected to other circuits through a pull-up resistor to create a digital signal that indicates which input voltage is higher.

The output stage of the LM339 is not suitable for driving capacitive loads, and the response time of the comparator is relatively slow compared to other high-speed comparators.


A comparator is an electronic circuit that compares two voltage inputs and outputs a digital signal indicating which input voltage is higher or lower. The output of a comparator is typically a logic signal, such as a high or low signal, that can be used to control other electronic devices, such as switches or LEDs.

Comparators have a wide range of applications in electronic circuits. For example, they can be used to compare a signal with a reference voltage and trigger an alarm or other action when the signal exceeds a certain threshold. They can also be used in voltage regulators to compare the output voltage with a reference voltage and adjust the output to maintain a stable voltage.

LM339 Schematic


1. Operation from Single or Dual Supplies
2. Common Mode Input Voltage Range to GND
3. Output Voltage Compatible with TTL, DTL, ECL, MOS and CMOS
4. Differential Input Voltage Range Equal to the Supply Voltage


1. Low power consumption
2. Wide operating voltage range
3. Four comparators in a single package
4. Open collector output stage allows easy interface with other circuits
5. Low input bias current and offset voltage
6. Wide temperature range


1. Square Wave Generator
2. Time Delay Generators
3. Pulse Generators
4. Multivibrators
5. High Voltage Digital Logic Gates
6. A/D Converters
7. MOS Clock Timers


1. Can the LM339 be used to drive a relay?

Yes, the open collector output stage of the LM339 can be used to drive a relay through a transistor and a diode. The diode is used to protect the transistor from voltage spikes generated by the relay coil when it is turned off.

2. What is the function of the hysteresis pin in the LM339?

The hysteresis pin (pin 5) in the LM339 is used to add positive feedback to the comparator, which can improve the stability and noise immunity of the comparator. When hysteresis is applied, the output of the comparator changes state at different input voltage levels depending on the direction of the input voltage change. This prevents the output from oscillating rapidly when the input voltage is close to the switching threshold.

LM339 Datasheet PDF Download

LM339 pdf

Other data sheets are available within the file: CA0139E, CA0139M, CA0239E, CA0239M96, CA0339E