LM339N

LM339N - Quad Differential Comparator

Overview

The LM339N is a quad differential comparator from the LM139 series, consisting of four independent precision voltage comparators designed for versatile analog signal comparison applications. This component features an exceptionally low input offset voltage (2mV max across all four comparators) and is optimized for operation from single or dual power supplies. Its ability to operate with input common-mode voltages including ground makes it particularly useful in single-supply configurations where input signals may approach the negative rail.

Engineered for reliability across industrial temperature ranges, the LM339N exhibits stable performance characteristics from 2V to 36V supply voltages. The device maintains consistent low current consumption regardless of supply voltage magnitude, making it suitable for both battery-powered and line-operated systems. The open-collector outputs allow flexible output voltage configuration and wired-OR connection of multiple comparators.

Key Features

• Quad Comparator Configuration: Four independent comparators in a single package
• Wide Supply Voltage Range: 2V to 36V DC operation (single or dual supply)
• Low Input Offset Voltage: 2mV maximum ensures accurate comparisons
• Ground-Including Input Range: Common-mode input includes ground in single-supply operation
• Low Supply Current: 0.8mA typical (independent of supply voltage)
• Open-Collector Outputs: Allows flexible output voltage configuration up to 36V
• Wired-OR Capable: Multiple comparator outputs can be connected together
• Industrial Temperature Range: -25°C to +85°C operation (LM339N)

Applications

The LM339N's robust design and flexible operating characteristics make it suitable for numerous analog signal processing applications:

• Voltage Monitoring Circuits: Over/under voltage detection systems
• Analog-to-Digital Interfaces: Signal conditioning for ADCs
• Oscillators and Timing Circuits: Square wave generation
• Sensor Interfaces: Threshold detection for temperature, light, or other sensors
• Power Supply Control: Voltage regulation feedback circuits
• Automotive Electronics: Robust enough for vehicular applications
• Industrial Control Systems: Process monitoring and control

Electrical Characteristics

All specifications are given for VCC = 5V, TA = 25°C unless otherwise noted:

Input Characteristics

• Input Offset Voltage: 2mV max (LM339A), 5mV max (LM339)
• Input Bias Current: 25nA typical
• Input Offset Current: 5nA typical
• Input Common-Mode Voltage Range: 0V to VCC-1.5V

Output Characteristics

• Output Saturation Voltage: 250mV typical at 4mA sink current
• Output Leakage Current: 0.1nA typical when off

Dynamic Characteristics

• Response Time (100mV overdrive): 1.3μs typical
• Propagation Delay: 300ns typical

Power Supply Characteristics

• Supply Voltage Range: 2V to 36V (single supply), ±1V to ±18V (dual supply)
• Supply Current (all four comparators): 0.8mA typical at 5V

Package Information

The LM339N is available in multiple package options with the PDIP-14 being the most common:

PDIP-14 Package Details

• Package Type: Plastic Dual In-Line Package
• Pin Count: 14
• Dimensions: 19.3mm x 6.35mm x 4.57mm (LxWxH)
• Pin Spacing: 2.54mm (100 mil) pitch
• Lead Material: Alloy 42 or copper alloy
• Lead Finish: Matte tin or solder-plated
• Moisture Sensitivity Level (MSL): MSL 1 (unlimited floor life)

Pin Configuration

• Pin 1: Output 2
• Pin 2: Output 1
• Pin 3: VCC+
• Pin 4: Inverting Input 1
• Pin 5: Non-Inverting Input 1
• Pin 6: Inverting Input 2
• Pin 7: Non-Inverting Input 2
• Pin 8: Non-Inverting Input 3
• Pin 9: Inverting Input 3
• Pin 10: Non-Inverting Input 4
• Pin 11: Inverting Input 4
• Pin 12: GND
• Pin 13: Output 4
• Pin 14: Output 3

Design Considerations

When implementing the LM339N in circuit designs, several important factors should be considered:

Input Protection

The device includes internal ESD protection diodes on all pins, but inputs should not exceed the supply voltage by more than 0.3V. For applications where input signals may exceed the supply rails, external clamping diodes are recommended.

Output Configuration

The open-collector outputs require pull-up resistors to the desired output high voltage level. Resistor values should be selected based on required switching speed and power consumption trade-offs (typically 1kΩ to 10kΩ). Multiple comparator outputs can be wire-OR'ed when connected to a common pull-up resistor.

Power Supply Decoupling

A 0.1μF ceramic capacitor should be placed as close as possible to the VCC pin to minimize supply noise. For applications with long power supply leads or noisy environments, additional bulk capacitance (1-10μF) may be required.

Thermal Considerations

While the LM339N has relatively low power dissipation, in high-temperature environments or when driving heavy output loads, thermal effects on performance should be evaluated. The PDIP-14 package has a thermal resistance of 80°C/W (junction-to-ambient).

Reliability and Qualification

The LM339N meets or exceeds the following reliability standards:

• ESD Protection: 1000V Human Body Model
• Operating Life: 100,000 hours MTBF at 25°C
• Manufacturing Process: Qualified to MIL-PRF-38535 Class H (industrial grade)