LM111J 8 Voltage Comparator

Overview

The LM111J 8 is a high-performance voltage comparator belonging to the LM111, LM211, and LM311 family of devices. Designed for precision applications, this comparator offers significantly lower input currents compared to older devices like the LM106 or LM710. It is engineered to operate across a broad range of supply voltages, from standard ±15V op-amp supplies down to a single 5V logic supply. The LM111J 8 is particularly notable for its compatibility with various logic families, including RTL, DTL, TTL, and MOS circuits, making it a versatile choice for both analog and digital systems.

Additionally, the LM111J 8 is capable of driving high-voltage loads such as lamps or relays, supporting switching voltages up to 50V at currents as high as 50mA. This makes it suitable for industrial control systems, automotive applications, and other environments requiring robust switching capabilities.

Features

• Low Input Current: Input currents are nearly a thousand times lower than older comparator models, reducing loading effects on signal sources.
• Wide Supply Voltage Range: Operates from ±15V down to a single 5V supply, providing flexibility in various circuit designs.
• Logic Compatibility: Output is compatible with RTL, DTL, TTL, and MOS logic families, enabling seamless integration into mixed-signal systems.
• High-Voltage Switching: Capable of driving relays or lamps with switching voltages up to 50V and currents up to 50mA.
• Fast Response Time: Designed for applications requiring quick decision-making, with minimal propagation delay.
• Stable Performance: Excellent temperature stability and noise immunity, ensuring reliable operation in harsh environments.

Applications

The LM111J 8 is widely used in applications requiring precise voltage comparisons and robust switching capabilities. Key application areas include:

• Industrial Control Systems: Used for threshold detection, level sensing, and motor control.
• Automotive Electronics: Employed in battery monitoring, overvoltage protection, and sensor interfacing.
• Power Supply Monitoring: Ideal for undervoltage/overvoltage lockout circuits in switch-mode power supplies.
• Analog-to-Digital Conversion: Serves as a critical component in ADC front-end circuits for signal conditioning.
• Relay and Lamp Drivers: Provides high-voltage switching for industrial and consumer applications.
• Oscillators and Pulse Generators: Used in timing circuits and waveform generation.

Electrical Characteristics

The following table summarizes the key electrical specifications of the LM111J 8 under typical operating conditions (unless otherwise noted):

Absolute Maximum Ratings

• Supply Voltage (V_CC): ±15V or +5V (single supply)
• Input Voltage Range: ±15V (differential), ±30V (common-mode)
• Output Voltage: 50V (max)
• Output Current: 50mA (max)
• Operating Temperature Range: -25°C to +85°C (LM111J)

Typical Performance Characteristics

• Input Bias Current: 150nA (max at 25°C)
• Input Offset Voltage: 2mV (max)
• Response Time: 200ns (typ for 5mV overdrive)
• Supply Current: 5mA (typ at ±15V)
• Common-Mode Rejection Ratio (CMRR): 90dB (typ)
• Power Supply Rejection Ratio (PSRR): 100dB (typ)

Package Information

The LM111J 8 is available in an 8-pin ceramic dual in-line package (DIP), which provides excellent thermal performance and mechanical durability. The package dimensions and pinout are as follows:

Package Dimensions

• Package Type: 8-Pin Ceramic DIP (J Package)
• Length: 9.81mm (max)
• Width: 6.35mm (max)
• Height: 3.3mm (max)
• Lead Pitch: 2.54mm

Pin Configuration

• Pin 1: Output
• Pin 2: Ground (GND)
• Pin 3: V_CC+ (Positive Supply)
• Pin 4: Non-Inverting Input (+)
• Pin 5: Inverting Input (-)
• Pin 6: Balance
• Pin 7: Balance/Strobe
• Pin 8: V_CC- (Negative Supply)

Conclusion

The LM111J 8 is a highly versatile voltage comparator that combines low input current, wide supply voltage range, and robust output drive capabilities. Its compatibility with multiple logic families and ability to handle high-voltage switching make it an excellent choice for a wide range of industrial, automotive, and consumer applications. With its stable performance under varying temperatures and excellent noise immunity, the LM111J 8 remains a reliable component for precision analog and mixed-signal designs.