NJM7909FA

Product Overview

• Category: Integrated Circuit (IC)
• Use: Voltage Regulator
• Characteristics:
  • Low dropout voltage
  • High ripple rejection
  • Short circuit protection
  • Thermal shutdown protection
• Package: TO-220F
• Essence: Negative Voltage Regulator
• Packaging/Quantity: Tube, 50 pieces per tube

Specifications

• Input Voltage Range: -35V to -10V
• Output Voltage: -9V
• Output Current: 1A
• Dropout Voltage: 2V (typical)
• Ripple Rejection Ratio: 60dB (typical)
• Operating Temperature Range: -40°C to +125°C

Detailed Pin Configuration

The NJM7909FA has a standard three-pin configuration:

1. Input Pin (Pin 1): Connects to the input voltage source.
2. Ground Pin (Pin 2): Connected to the ground or common reference point.
3. Output Pin (Pin 3): Provides the regulated output voltage.

Functional Features

• Negative Voltage Regulation: The NJM7909FA regulates the input voltage to a stable -9V output voltage.
• Low Dropout Voltage: The IC maintains regulation even when the input voltage is close to the output voltage.
• High Ripple Rejection: Filters out noise and ripple present in the input voltage.
• Short Circuit Protection: Safeguards the IC from damage in case of a short circuit.
• Thermal Shutdown Protection: Prevents overheating by shutting down the IC when the temperature exceeds a certain threshold.

Advantages and Disadvantages

Advantages: - Stable and accurate negative voltage regulation. - Wide operating temperature range. - Built-in protection features enhance reliability. - Compact TO-220F package allows for easy integration.

Disadvantages: - Dropout voltage may cause power dissipation and efficiency loss. - Limited output current capability (1A).

Working Principles

The NJM7909FA is a linear voltage regulator that uses a negative feedback mechanism to maintain a constant -9V output voltage. It consists of a series pass transistor, error amplifier, and voltage reference. The error amplifier compares the output voltage with a fixed reference voltage and adjusts the series pass transistor accordingly to regulate the output voltage.

Detailed Application Field Plans

The NJM7909FA is commonly used in various applications requiring a stable -9V power supply. Some typical application fields include:

1. Audio Equipment: Provides a regulated negative voltage for audio amplifiers and preamplifiers.
2. Industrial Control Systems: Used in control circuits, sensors, and actuators that require a negative voltage source.
3. Automotive Electronics: Provides a reliable negative voltage for automotive systems such as car radios and navigation systems.
4. Test and Measurement Instruments: Used in laboratory equipment and test setups that require a negative voltage reference.

Detailed and Complete Alternative Models

1. LM7909: Similar negative voltage regulator IC manufactured by Texas Instruments.
2. MC79L09: Negative voltage regulator IC produced by ON Semiconductor.
3. KA7909: Another alternative from Fairchild Semiconductor.

These alternative models offer similar functionality and can be used as substitutes for the NJM7909FA in various applications.

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