The MC7905 is a three-terminal negative voltage regulator manufactured by Fairchild/ON Semiconductor. This device is designed to provide a fixed -5V output voltage with a typical output current of 1A. It is part of the MC79xx series of regulators, known for their simplicity, reliability, and ease of use in various electronic applications.

Applications:

• Negative Voltage Power Supplies: Providing a regulated -5V supply for analog circuits and other components.
• Linear Regulators for Microprocessors and Logic Circuits: Supplying negative voltage rails required by certain ICs.
• On-Card Regulation: Regulating voltage locally on circuit boards to minimize noise and voltage drops.
• Post Regulation for Switching Power Supplies: Improving the output voltage accuracy and stability of switching regulators.
• Instrumentation and Measurement Equipment: Providing a stable negative voltage reference for accurate measurements.

Features:

• Fixed Output Voltage of -5V: Provides a stable and predictable negative voltage.
• Output Current up to 1A: Capable of supplying a continuous current of 1A to the load.
• Internal Thermal Overload Protection: Protects the regulator from damage due to overheating.
• Internal Short-Circuit Current Limiting: Limits the output current to prevent damage from short circuits.
• Output Transistor Safe-Area Compensation: Ensures reliable operation under various load conditions.
• No External Components Required: Simplifies the design process and reduces BOM cost.

Benefits:

• Simplified Design: Requires no external components, reducing design complexity and time.
• Reliable Operation: Built-in protection features ensure robust and reliable operation.
• Cost-Effective: Reduces BOM cost and simplifies manufacturing.
• Stable Output Voltage: Provides a consistent and predictable negative voltage.
• Easy to Use: Simple three-terminal configuration for easy integration into circuits.

Additional Details:

The MC7905 requires a minimum input voltage of approximately -7V to maintain a stable -5V output. It is typically available in a TO-220 package, which allows for easy heat sinking to dissipate power. The regulator features internal thermal overload protection, which shuts down the output if the junction temperature exceeds a safe limit. It also includes short-circuit current limiting, which prevents damage from short circuits by limiting the output current. The MC7905 is a robust and reliable negative voltage regulator suitable for a wide range of applications requiring a stable -5V supply.