The MM74C922 is a 16-key encoder manufactured by Fairchild Semiconductor, now part of ON Semiconductor. This device is designed to encode the closure of any one of 16 single pole single throw (SPST) switches into a 4-bit binary code. The encoded output, along with a Data Available (DA) strobe, simplifies the interface with digital systems.

Applications

• Keyboards
• Control Panels
• Remote Control Systems
• Industrial Control Interfaces
• Simple Data Entry Systems

Features

• Encodes 16 Keys: Converts switch closures to a 4-bit binary code.
• Data Available Strobe: Indicates a valid key closure.
• Low Power Consumption: Operates efficiently with minimal power.
• Wide Operating Voltage Range: Flexible power supply requirements.
• TTL Compatible Outputs: Easy interfacing with other TTL logic.

Benefits

• Simplified Keyboard Interface: Reduces the complexity of interfacing a keyboard to a digital system.
• Reduced Wiring: Encodes multiple key presses into a smaller number of output lines.
• Low Power Operation: Suitable for battery-powered applications.
• Ease of Integration: TTL compatible outputs simplify interfacing with microprocessors and other digital logic.
• Cost-Effective: Provides a simple and efficient solution for key encoding.

The MM74C922 is commonly used in applications where a simple and low-cost keyboard interface is required. Its encoding capabilities reduce the number of input lines needed by a microprocessor or microcontroller, freeing up valuable I/O pins. The Data Available strobe signal ensures that the system only reads valid data.

Technical Specifications:

Number of Keys Encoded: 16. Output Code: 4-bit binary. Supply Voltage: 3V to 15V. Output Compatibility: TTL. Operating Temperature Range: -40°C to +85°C. Package: DIP-24.