The STMicroelectronics L7805CV is a linear voltage regulator designed to provide a stable output voltage of 5V from a higher input voltage. This device is widely used in various power supply applications, offering a reliable solution for powering circuits and devices that require a steady and regulated 5V supply. It is part of the L78xx series of voltage regulators, which includes other fixed-output regulators for different voltage levels such as 12V, 15V, and 24V.
The L7805CV is a three-terminal device, typically used in applications such as consumer electronics, industrial equipment, embedded systems, and communications devices. Its robustness, ease of use, and availability make it a popular choice for engineers and designers when building power supplies.
## Key Specifications
## General Features
* Output Voltage: The primary feature of the L7805CV is its fixed output voltage of 5V, which is regulated and stable over a wide range of input voltages. It ensures that the output remains constant, even with fluctuations in the input voltage or load conditions.
* Output Current: The device can supply a maximum output current of 1A. This makes it suitable for a variety of applications, from small devices with low current demands to larger systems that require moderate current.
* Low Dropout Voltage: The L7805CV typically has a dropout voltage of around 2V at 1A output current, meaning that the input voltage must be at least 7V for proper regulation at full load. At lower loads, the dropout voltage can be lower, but it is crucial to ensure that the input voltage remains sufficiently higher than 5V for stable operation.
## Electrical Characteristics
* Input Voltage Range: The L7805CV requires an input voltage that is higher than the regulated output voltage. The input voltage should typically be between 7V and 35V for proper operation. The device can handle input voltages beyond 35V but may overheat or experience damage if the voltage exceeds the absolute maximum rating.
* Output Voltage Accuracy: The L7805CV has a voltage tolerance of typically ±2%. This means that the output voltage will typically remain within 5V ± 2% (i.e., between 4.9V and 5.1V) under typical conditions.
* Regulation: The L7805CV features load regulation and line regulation, ensuring stable output even as the load current or input voltage fluctuates. The load regulation is typically ±50mV at 1A, and the line regulation is typically ±10mV for a 10V change in input voltage.
## Thermal and Power Dissipation
* Thermal Overload Protection: The L7805CV includes an internal thermal overload protection feature. If the device’s temperature exceeds a certain threshold (typically 150°C), the regulator will shut down to prevent damage. This feature ensures that the device remains safe and functional in high-temperature environments or when subjected to excessive power dissipation.
* Short Circuit Protection: The regulator also includes built-in short-circuit protection, which ensures that the device will not be damaged if the output is shorted to ground. In such a case, the regulator will limit the current or enter a shutdown state until the fault condition is cleared.
* Power Dissipation: When operating, the L7805CV dissipates power as heat. The power dissipation is calculated based on the input voltage, output voltage, and output current using the formula:
$$
P = (V_{in} - V_{out}) imes I_{out}
$$
For example, if the input voltage is 12V and the output current is 1A, the power dissipation would be:
$$
P = (12V - 5V) imes 1A = 7W
$$
This heat dissipation must be managed to prevent the regulator from overheating. The L7805CV typically requires a heatsink or adequate ventilation in applications where high power dissipation occurs.
## Package and Integration
* Package Type: The L7805CV comes in a TO-220 package, a popular package for voltage regulators and power transistors. The TO-220 package allows for effective heat dissipation and is easy to mount on a heatsink if needed. It also provides reliable and robust mechanical and electrical connections.
* Pins Configuration:
* Pin 1: Input (V\_in) – The input voltage is applied to this pin.
* Pin 2: Ground (GND) – This pin is connected to the ground of the circuit.
* Pin 3: Output (V\_out) – This pin provides the regulated output voltage of 5V.
## Applications
The L7805CV is widely used in various applications that require stable and regulated 5V power. Some typical applications include:
1. Power Supplies: The L7805CV is commonly used in linear power supplies, where it provides a simple solution to convert higher DC voltages into a stable 5V output. It is often used in benchtop power supplies, test equipment, and battery chargers.
2. Arduino and Embedded Systems: Many Arduino and Raspberry Pi boards, as well as other embedded systems, require a stable 5V power supply. The L7805CV is used in these systems to ensure reliable operation, especially when the input voltage is higher than 5V.
3. Consumer Electronics: In consumer electronics such as radios, toys, LED drivers, and cameras, the L7805CV provides the necessary voltage regulation to power low-voltage circuits and components.
4. Communication Equipment: The device is used in communication systems, such as telecom equipment, where a stable 5V is required for powering logic circuits and other sensitive components.
5. Industrial Equipment: The L7805CV is used in industrial automation systems, sensors, and PLC circuits that require stable 5V power for their control and data acquisition systems.
## Key Features and Benefits
1. Fixed 5V Output: The L7805CV provides a stable 5V output, making it ideal for systems that require a constant supply voltage.
2. High Output Current Capability: It can provide up to 1A of output current, making it suitable for a range of applications requiring moderate current supply.
3. Thermal and Short Circuit Protection: Built-in thermal overload and short circuit protection features ensure that the device operates safely and reliably even in fault conditions.
4. Low Dropout Voltage: The L7805CV has a low dropout voltage, which means it can maintain the 5V output even when the input voltage is only slightly above 5V, making it useful in applications with limited input voltage headroom.
5. Compact and Robust: The device comes in a TO-220 package, which is easy to mount and provides good thermal dissipation, especially in high-power applications.
6. Wide Input Voltage Range: The device operates with an input voltage range of 7V to 35V, providing flexibility for use in a variety of systems and designs.
7. Low Cost: The L7805CV is cost-effective, making it an ideal choice for projects or products with budget constraints while still requiring reliable voltage regulation.
## Conclusion
The STMicroelectronics L7805CV is a highly reliable and widely used 5V voltage regulator that provides a stable and regulated output voltage with a wide input voltage range. It is ideal for powering consumer electronics, industrial equipment, embedded systems, and communication devices. With features such as thermal overload protection, short-circuit protection, low dropout voltage, and compact packaging, the L7805CV is a versatile solution for various voltage regulation needs. It is well-suited for applications where stability, safety, and efficiency are essential.
