L78L05ACUTR Detailed explanation of pin function specifications and circuit principle instructions

The L 78L05 ACUTR is a voltage regulator produced by STMicroelectronics. It is part of the L78 series, which provides positive voltage regulation. This particular part is designed for applications requiring a 5V output with low current consumption, typically used for powering low-power digital circuits or other small devices.

Pin Function Specifications:

Package Type

The L78L05ACUTR is commonly available in a TO-92 package, which has 3 pins.

Here is a breakdown of the pin functions and specifications:

Pin Number Pin Name Pin Function 1 Input (V_in) The input pin for the unregulated voltage. The voltage must be higher than 5V (typically 7V to 35V) for proper regulation. 2 Ground (GND) The ground pin is the common reference point for the circuit, connected to the system ground. 3 Output (V_out) The regulated output voltage (5V). This pin provides the stable 5V output to the load.

Pin Function Description (Detailed):

Input Pin (Pin 1): This is the unregulated input voltage that will be converted into the 5V regulated output. The input voltage should always be higher than 5V to ensure that the regulator can step it down appropriately. Recommended Input Range: 7V to 35V. A higher voltage than this could potentially damage the IC, and a lower voltage would result in incorrect regulation. Filtering capacitor s are often used on this pin to reduce input noise and ensure a stable voltage. Ground Pin (Pin 2): This pin serves as the common reference for the input and output voltages. It is essential that the ground of the regulator is connected to the system ground to ensure proper operation. The ground pin should also be kept clean of noise to ensure proper voltage regulation. Output Pin (Pin 3): The output pin provides a stable 5V regulated output voltage. The output is designed to supply current to small loads (usually up to 100mA). The output voltage remains relatively stable despite variations in the input voltage, provided the input is within the specified range. Capacitors are often added on the output to improve transient response and reduce noise.

20 Commonly Asked Questions (FAQ) Regarding L78L05ACUTR:

Q1: What is the output voltage of the L78L05ACUTR? A1: The L78L05ACUTR provides a regulated 5V output voltage.

Q2: What is the input voltage range for the L78L05ACUTR? A2: The recommended input voltage range is between 7V and 35V.

Q3: What is the maximum current the L78L05ACUTR can supply? A3: The L78L05ACUTR can supply a maximum output current of approximately 100mA.

Q4: What type of package does the L78L05ACUTR come in? A4: The L78L05ACUTR comes in a TO-92 package with 3 pins.

Q5: Can the L78L05ACUTR be used for higher current applications? A5: No, the L78L05ACUTR is designed for low-current applications (up to 100mA). For higher current applications, other voltage regulators should be considered.

Q6: What is the purpose of the ground pin (Pin 2)? A6: The ground pin serves as the common reference point for both input and output voltages, ensuring proper voltage regulation.

Q7: Is the L78L05ACUTR short-circuit protected? A7: Yes, the L78L05ACUTR has internal short-circuit protection to safeguard the regulator and circuit in the event of a short.

Q8: Does the L78L05ACUTR have thermal overload protection? A8: Yes, the L78L05ACUTR is equipped with thermal overload protection to prevent damage in case of overheating.

Q9: Can the L78L05ACUTR be used with other input voltages? A9: The L78L05ACUTR is designed specifically for a 5V output. Input voltages above 5V (within the recommended range) will be regulated to 5V, but lower input voltages will not work properly.

Q10: What is the typical dropout voltage of the L78L05ACUTR? A10: The typical dropout voltage of the L78L05ACUTR is around 2V, meaning the input voltage needs to be at least 7V for proper regulation to 5V.

Q11: How does the L78L05ACUTR compare to other voltage regulators? A11: The L78L05ACUTR is a linear voltage regulator designed for low current applications. It is less efficient than switching regulators but is simpler and provides stable regulation for small devices.

Q12: Is there a need for external capacitors with the L78L05ACUTR? A12: Yes, external capacitors are recommended for both the input and output to improve stability and transient response.

Q13: What are typical applications for the L78L05ACUTR? A13: Typical applications include powering small digital circuits, microcontrollers, sensors, or other low-power devices.

Q14: Can the L78L05ACUTR be used in automotive applications? A14: Yes, the L78L05ACUTR can be used in automotive applications, provided the input voltage remains within the specified range (7V to 35V).

Q15: What happens if the input voltage exceeds 35V? A15: Exceeding 35V may cause permanent damage to the L78L05ACUTR due to the voltage rating limitations.

Q16: Can the output voltage of the L78L05ACUTR be adjusted? A16: No, the L78L05ACUTR has a fixed output voltage of 5V and cannot be adjusted.

Q17: How should the ground pin be connected? A17: The ground pin should be connected to the common ground of the circuit to ensure proper operation.

Q18: What is the output voltage tolerance of the L78L05ACUTR? A18: The output voltage tolerance is typically ±2%, meaning it will provide between 4.9V and 5.1V depending on variations.

Q19: How does the L78L05ACUTR handle power dissipation? A19: The power dissipation is the difference between the input voltage and the output voltage, multiplied by the output current. It is important to ensure adequate heat dissipation in applications requiring continuous operation.

Q20: Can the L78L05ACUTR be used in parallel to increase current supply? A20: No, the L78L05ACUTR should not be used in parallel with other regulators to increase current supply. For higher current applications, other solutions should be used.

If you require further details or additional questions answered, feel free to ask!