LM311 Voltage Comparator IC Single/Dual Supply Compatible

The LM311 Comparator IC is designed to determine which of two input voltages is higher and provide a corresponding output state. It is widely used in analog signal-processing and control circuits where voltage levels need to be detected or compared.

Its open-collector output provides flexibility when interfacing with different logic voltage levels. A suitable external pull-up resistor is normally required to obtain a defined high output level.

Features

• LM311 voltage comparator IC
• Single or dual supply operation
• Low input bias current
• Maximum input bias current of 250nA
• Maximum input offset current of 50nA
• Open-collector output
• Fast switching response
• Differential input voltage capability
• Offset voltage null capability
• Strobe capability
• Through-hole DIP-8 package
• Suitable for analog-to-digital signal interfacing

Applications

• Voltage level detection
• Threshold detectors
• Zero-crossing detectors
• Signal comparison
• Waveform conversion
• Signal conditioning
• Logic-level interfacing
• Pulse and switching circuits
• Oscillator and timing circuits
• Battery voltage monitoring
• Sensor signal detection
• DIY electronics and educational projects

How It Works / Use Guide

The LM311 compares the voltage applied to its two input terminals.

1. Connect the IC to an appropriate single or dual power supply.
2. Apply the reference voltage to one comparator input.
3. Apply the signal being monitored to the other input.
4. The comparator determines the relative voltage between the two inputs.
5. The open-collector output changes state according to the input comparison.
6. Use an appropriate pull-up resistor on the open-collector output when required.
7. For applications requiring improved comparison accuracy, the offset-null function can be configured according to the applicable circuit design.
8. For noise-sensitive applications, use suitable grounding, decoupling, and signal filtering techniques.

Important Notes

• The LM311's output is open collector, so an external pull-up resistor is generally required for a logic-level output.
• Do not exceed the specified supply voltage or input voltage limits.
• The differential input voltage rating should not be confused with the recommended operating input range.
• Proper power-supply decoupling is recommended for stable operation.
• The maximum power dissipation depends on the package and operating conditions.
• Use the correct pin configuration when designing or assembling the circuit.
• The exact electrical characteristics can vary between manufacturers and versions of the LM311.
• Always check the datasheet corresponding to the actual IC manufacturer and package before designing a critical circuit.

Package Includes

• 1 × LM311 Voltage Comparator IC (DIP-8)