The LM339 is a versatile quad voltage comparator IC containing four independent precision voltage comparators in a single package. It is designed to compare two analog voltage levels and provide a digital output indicating which input voltage is higher.
The LM339 can operate from a single power supply or dual supplies, making it suitable for a wide variety of analog and digital interface applications. Its open-collector outputs allow easy interfacing with different logic levels and enable multiple comparator outputs to be connected together when required.
It is commonly used in voltage monitoring, level detection, sensor circuits, battery monitoring, threshold detection, oscillators, and signal-conditioning applications.
Key Features
-
4 independent voltage comparators in one IC
- Wide operating supply voltage range
- Supports single or dual power supplies
- Low supply current
- Open-collector outputs
- Compatible with many TTL, CMOS, and logic circuits when properly configured
- Wide input common-mode voltage range
- Suitable for analog-to-digital signal interfacing
- Reliable threshold and level detection
- 14-pin package
How It Works
Each comparator contains two inputs:
- Non-Inverting Input (+)
- Inverting Input (-)
The LM339 compares the voltage applied to these two inputs and changes its output state according to their relationship.
This allows the IC to detect when an analog signal crosses a predetermined voltage threshold.
Because the LM339 uses open-collector outputs, an external pull-up resistor is normally required at each output.
Four Independent Comparators
The LM339 integrates four separate comparator circuits into a single IC.
This allows one LM339 to monitor several signals or voltage thresholds simultaneously, reducing the number of components required in multi-channel applications.
Technical Specifications
| Specification |
Details |
| Part Number |
LM339 |
| Device Type |
Voltage Comparator |
| Number of Comparators |
4 |
| Output Type |
Open Collector |
| Supply Type |
Single or Dual Supply |
| Typical Single Supply Range |
2V to 36V* |
| Typical Dual Supply Range |
±1V to ±18V* |
| Package |
14-Pin |
| Application |
Analog Voltage Comparison & Level Detection |
Exact electrical ratings can vary slightly depending on the LM339 manufacturer/version. Refer to the specific device datasheet when designing near the operating limits.
Applications
The LM339 is suitable for:
- Voltage level detection
- Battery voltage monitoring
- Over-voltage and under-voltage detection
- Sensor interface circuits
- Threshold detection
- Zero-crossing detection
- Window comparator circuits
- Oscillators
- Waveform generation
- Signal conditioning
- Alarm circuits
- Power supply monitoring
- Light and temperature sensing circuits
- Microcontroller interfacing
- DIY electronics and breadboard projects
The LM339 Quad Voltage Comparator IC is a practical solution for projects requiring multiple analog voltage comparisons in a compact and easy-to-use package.
