Pinout:
- The LM7912 has three pins:
- Pin 1 (Input): Input voltage (typically a positive voltage, which is to be regulated down to a negative voltage).
- Pin 2 (Ground): Ground reference for the IC.
- Pin 3 (Output): Regulated negative output voltage.
The LM7912 is commonly used in electronic circuits to provide a stable negative voltage. It is a linear voltage regulator that operates by dissipating excess power as heat, making it suitable for low to medium-current applications. Some of the features of LM7912 include:
- Fixed negative output voltage: The LM7912 provides a fixed regulated negative output voltage, typically -12 volts.
- Output current capability: The maximum output current it can handle is usually around 1A to 1.5A, depending on the manufacturer's version.
- Thermal overload protection: The IC has built-in thermal overload protection, which helps prevent damage due to excessive heat.
Equivalents and Replacement:
If the LM7912 is not available, you can use other negative voltage regulators with similar specifications. Some equivalent parts from different manufacturers include:
- MC7912
- UA7912
- KA7912
- L7912
Always ensure that the replacement part has the same voltage (e.g., -12V) and similar or higher current handling capability.
Where & How to Use:
The LM7912 is widely used in various electronic circuits where a stable negative voltage is required. Some common applications include:
- Power supply circuits: To generate a regulated negative voltage for specific components or subsystems.
- Audio circuits: To provide a negative bias voltage for amplifiers or audio processing stages.
- Analog circuits: In certain analog designs, a negative voltage reference may be necessary.
- Testing and prototyping: It can be used to provide a negative power supply during circuit development and testing.
To use the LM7912, you should connect the input pin to the positive voltage source, the ground pin to the circuit ground, and the output pin to the circuit requiring the regulated -12V. Make sure to add proper input and output capacitors for stability.
Applications:
- Negative power supply for operational amplifiers (op-amps) and other ICs.
- Bipolar power supply configurations where both positive and negative voltages are required.
- Negative voltage biasing in audio and RF circuits.
Remember, as a linear regulator, the LM7912 is not as efficient as switching regulators, especially when the input-output voltage difference is large, as it dissipates excess power as heat. So, for high-current or high-voltage applications, a switching regulator might be a better choice.
Important Note:
As technology evolves, newer and more efficient voltage regulators may become available, so it's always a good idea to check for the latest options and improvements in voltage regulation. Always refer to the datasheet and application notes provided by the manufacturer for proper usage and design considerations.
Datasheet
To Download the datasheet just copy and paste the below link in your browser.
https://cdn.datasheetspdf.com/pdf-down/L/M/7/LM7912_NationalSemiconductor.pdf
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