LM319N

LM319N: Precision High-Speed Dual Comparator

Overview

The LM319N is a precision high-speed dual comparator fabricated on a single monolithic chip. Designed for versatility, it operates over a wide range of supply voltages, including a single 5V logic supply and ground. The LM319N offers superior performance with higher gain and lower input currents compared to older devices like the LM710. Its uncommitted collector output stage ensures compatibility with RTL, DTL, and TTL logic families, while also enabling direct driving of lamps and relays with currents up to 25mA. This makes the LM319N a robust choice for applications requiring fast response times and precision.

Features

• Dual Comparator Design: Two independent comparators on a single chip for space-efficient designs.
• Wide Supply Voltage Range: Operates from a single 5V supply up to ±15V, accommodating diverse applications.
• High Gain: Provides superior signal amplification compared to legacy devices like the LM710.
• Low Input Current: Minimizes loading effects on signal sources, enhancing accuracy.
• Uncommitted Output Stage: Open-collector outputs allow flexible interfacing with RTL, DTL, and TTL logic.
• High Output Drive Capability: Capable of driving lamps, relays, or other loads up to 25mA.
• Fast Response Time: Optimized for high-speed switching applications.
• Stable Operation: Designed for reliable performance across varying temperatures and conditions.

Applications

The LM319N is suited for a broad range of applications, including:

• Voltage Level Detection: Ideal for monitoring and threshold detection in power supplies and battery management systems.
• Analog-to-Digital Conversion: Used as a front-end comparator in ADC circuits.
• Oscillators and Timers: Facilitates precise timing control in waveform generation.
• Signal Conditioning: Enhances signal integrity in sensor interfaces and instrumentation.
• Logic Level Shifting: Bridges different logic families (RTL, DTL, TTL) due to its flexible output stage.
• Relay and Lamp Drivers: Directly drives inductive or resistive loads without additional buffering.
• Industrial Control Systems: Provides reliable switching in automation and control circuits.

Electrical Characteristics

The following table summarizes key electrical specifications for the LM319N under typical operating conditions (unless otherwise noted):

• Supply Voltage Range: 5V to ±15V
• Input Offset Voltage: 2mV (max)
• Input Bias Current: 150nA (max)
• Response Time: 80ns (typical) for a 10mV overdrive
• Output Sink Current: 25mA (max)
• Common-Mode Rejection Ratio (CMRR): 90dB (typical)
• Operating Temperature Range: -25°C to +85°C

Package Information

The LM319N is available in a standard 14-pin dual in-line package (DIP), ensuring compatibility with through-hole PCB designs. Key package details include:

• Package Type: PDIP-14 (Plastic Dual In-Line Package)
• Pin Count: 14
• Dimensions: 19.3mm x 6.35mm x 4.57mm (L x W x H)
• Pin Configuration:
  • Pins 1 & 14: Outputs for Comparator 1 and 2
  • Pins 2 & 13: Inverting Inputs
  • Pins 3 & 12: Non-Inverting Inputs
  • Pins 4 & 11: V- (Negative Supply)
  • Pins 5 & 10: Ground (for single-supply operation)
  • Pins 6 & 9: Unused (NC)
  • Pins 7 & 8: V+ (Positive Supply)

Detailed Description

The LM319N integrates two high-speed comparators with precision performance characteristics. Each comparator features differential inputs (inverting and non-inverting) and an open-collector output, allowing for flexible configuration. The device's internal architecture ensures minimal propagation delay, making it suitable for applications requiring rapid decision-making based on analog input thresholds.

The uncommitted output stage is a standout feature, enabling direct interfacing with various logic families or load types. When used with a pull-up resistor, the output can swing close to the positive supply rail, while the open-collector design allows for ground-referenced switching. This versatility is further enhanced by the device's wide supply voltage range, supporting both single and dual-supply configurations.

Design Considerations

When incorporating the LM319N into a circuit, consider the following:

• Power Supply Decoupling: Use a 0.1µF ceramic capacitor close to the supply pins to minimize noise.
• Output Pull-Up Resistor: Select a value based on load requirements and desired switching speed (typically 1kΩ to 10kΩ).
• Input Protection: For harsh environments, add clamping diodes to prevent input overvoltage.
• Thermal Management: While the LM319N has low power dissipation, ensure adequate airflow in high-density layouts.

Conclusion

The LM319N is a versatile, high-performance dual comparator offering precision, speed, and flexibility. Its robust design and wide operating range make it suitable for diverse applications, from industrial controls to consumer electronics. By leveraging its open-collector outputs and low input currents, designers can achieve efficient and reliable circuit solutions.