L7805CV Specifications, Applications and Design Considerations
22 February 2024
Ⅲ. L7805CV symbol, footprint and pin configuration
Ⅴ. Precautions for using L7805CV
Ⅵ. Absolute maximum ratings of L7805CV
Ⅶ. Design considerations for L7805CV
Ⅷ. How to detect the quality of L7805CV?
The L7805CV is a linear voltage regulator integrated circuit designed to provide a constant 5V output to electronic devices. It has the characteristics of high stability, high accuracy, small peak noise and small temperature drift. It is usually used in sensors, microcontrollers, power supplies, LCD displays, building automation systems and other electronic equipment. This article will introduce the specific information of L7805CV in terms of specifications, applications and design considerations etc..
L7805CV is a three-terminal positive voltage regulator with an output voltage range of 4.75V to 5.25V and a quiescent current of 4.2mA to 8mA. The output current of this regulator can reach 1.5A without external compensation components. It has a built-in current limiting protection circuit to effectively prevent component burnout caused by load short circuit. As a three-terminal voltage regulator, “78” represents positive voltage regulation, and the corresponding “79” represents negative voltage regulation. The “05” represents the value of the transmission voltage. Therefore, the L7805CV is a three-terminal voltage regulator of positive 5 volts. Typically, this device is a drop-in replacement, maintaining an output voltage between 4.75 and 5.25 volts and a quiescent current between 4.2 and 8 mA.
Alternatives and equivalents:
• BA17805T
• L7805ABP
• L7805C-V
• L78M05CV
• It adopts through-hole mounting.
• L7805CV is manufactured by STMicroelectronics.
• L7805CV belongs to the category of linear voltage regulators.
• L7805CV has 3 pins and is packaged in TO-220 and tube.
• This voltage regulation device has an operating temperature range of 0°C to 125°C.
• Its load regulation is 100mV and its quiescent current is 4.3mA.
• L7805CV has a length of 10.4 mm, a width of 4.6 mm, and a height of 9.15 mm.
The above figure shows the symbol, footprint and pin configuration of L7805CV respectively. Among them, it has 3 pins, whose names and functions are as follows:
1. Input: accepts the voltage to be adjusted
2. Output: provides a fixed and stable voltage
3. Ground: ground pin
• Sensor interface: Many sensors require a stabilized voltage to operate. By using the L7805CV, we can ensure that sensors receive the stable power supply they need. No matter how the input voltage fluctuates, the L7805CV is able to stabilize the voltage output in the range of 4.75V to 5.25V through its internal circuitry and regulation mechanism. In this way, the sensor is able to obtain a constant and reliable power supply to ensure its normal operation and high accuracy measurement.
• Battery charger: The L7805CV can be used to design a simple battery charger circuit. For example, it can be used to control the charging current and ensure that the charging voltage is within a safe range, thus avoiding damage to the battery due to over- or under-voltage.
• Power supply: The L7805CV can be used as the main power supply for electronic devices such as sensors, displays and microcontrollers. By connecting the input voltage (usually a higher voltage) to the input pin of the L7805CV, connecting ground to the ground pin, and then extracting +5V from the output pin, it can be supplied to the target device.
• Automotive electronics: The L7805CV can provide a stable power supply for audio devices, displays, and control modules, among others. For example, displays, an integral part of modern electronic devices, also require stable power to ensure clear display of images and text. From traditional LCD displays to modern OLED displays, the L7805CV can provide reliable power support. By ensuring stable power supply to the display, the L7805CV helps to reduce problems such as image flickering, color distortion, etc., so that users can get a clearer and more realistic visual experience.
When using the L7805CV chip, we need to pay attention to the following things to ensure its normal operation and long life:
1. Avoid short circuit and overcurrent: The L7805CV chip has short circuit protection and overcurrent protection functions. However, in order to ensure the safety of the system and the life of the chip, short circuits and excessive current loads should be avoided as much as possible.
2. Temperature control: The L7805CV chip has a certain amount of heat dissipation, so appropriate heat dissipation measures and temperature control need to be considered in the design. Make sure the chip operates within its rated operating temperature range and avoid damage from overheating.
3. Output current limit: The maximum output current capability of the L7805CV chip is 1A. When designing a circuit, it is necessary to reasonably select the chip according to the load current requirements and ensure that its rated output current is not exceeded to avoid chip overload and damage.
4. Heat dissipation problem: Since the L7805CV chip is a linear voltage regulator, it will produce power loss and heat dissipation under high load. Therefore, good heat dissipation measures need to be considered when designing the circuit.
5. Input voltage range: The input voltage range of the L7805CV chip is usually 7V to 35V. When using this chip, ensure that the input voltage does not exceed its specified maximum value, and avoid input voltage that is too low to ensure normal operation.
6. Ensure good grounding: When connecting the L7805CV chip, ensure a good grounding connection. Good grounding can provide a stable reference potential, reduce the impact of stray noise on the chip, and improve the reliability of the system.
7. Pay attention to the input and output pin connections: Properly connecting the input and output pins of the L7805CV chip is crucial. Ensure the input voltage is connected to the VIN pin, the load to the VOUT pin, and the GND pin to ground. Incorrect connections may lead to malfunction or circuit failure.
8. Maintain a low-noise environment: Linear regulator chips are sensitive to noise, so they need to maintain a low-noise environment. When designing a circuit, taking appropriate filtering measures, such as adding capacitors and filter circuits, can effectively reduce noise levels and improve chip performance.
Absolute maximum ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied.
The L78 Series of fixed voltage regulators are designed with thermal overload protection that shuts down the circuit when subjected to an excessive power overload condition, internal short-circuit protection that limits the maximum current the circuit will pass, and output transistor safe-area compensation that reduces the output short-circuit current as the voltage across the pass transistor is increased. In numerous low-current scenarios, compensation capacitors may be unnecessary. Nonetheless, it is advisable to employ a bypass capacitor at the regulator input if the regulator connects to the power supply filter over extended distances or encounters significant output load capacitance. Choosing an input bypass capacitor with robust high-frequency characteristics is crucial for ensuring stable operation across varying load conditions. A 0.33 μF or larger tantalum, mylar or other capacitor having low internal impedance at high frequencies should be chosen. The bypass capacitor should be mounted with the shortest possible leads directly across the regulators input terminals. Normally good construction techniques should be used to minimize ground loops and lead resistance drops since the regulator has no external sense lead.
The addition of an operational amplifier allows adjustment to higher or intermediate values while retaining regulation characteristics. The minimum voltage achieved through this setup surpasses the regulator voltage by 2 volts.
Note:
1. Although no output capacitor is needed for stability, it does improve transient response.
2. Required if regulator is located an appreciable distance from power supply filter.
First, we need to check the circuit connections to make sure that the L7805CV is properly connected to the circuit and that the input voltage is within its specified operating range, which is usually 7V to 35 V. Next, we will use a digital voltmeter or multi-purpose meter to measure the input and output voltages of the L7805CV. The input voltage should be within the specified range and the output voltage should be close to +5 V. If the output voltage is much lower or higher than +5 V, this may indicate a problem with the chip. With the input and output circuits disconnected, we will use a resistance meter to check for shorts between the input and output pins. Normally, there should not be a short between the input and output. Finally, we will provide some voltage and load to the input and output pins of the L7805CV and observe if the chip overheats. If the chip overheats under normal load, this could indicate a problem. If all of the above tests fail to reveal a problem, but the circuit still does not work properly, we may consider replacing the current chip with another working L7805CV chip to see if the problem is resolved.
Frequently Asked Questions
1. What is the meaning of L7805CV?
L7805CV is a three terminal linear voltage regulator IC with a fixed output voltage of 5V which is useful in a wide range of applications.
2. What is L7805CV used for?
This standard L7805CV linear regulator from STMicroelectronics will give you control over the voltage levels of your circuit. Its typical dropout voltage at current is 2@1AV. This voltage regulation device's single output can produce a current up to 1.5 A.
3. What is the difference between L7805CV and L7805CP?
The difference is in packaging. The L7805CP on the left is an all plastic package. the L7805CV, on the right, has a metal tab. As long as your application doesn't depend on the ground connection on the metal tab, it should work.
4. What type of transistor is L7805CV?
L7805CV is a type of voltage regulator in TO-220. It can offer local on-card regulation and eliminate the distribution issues caused by single-point control. Each model has internal current limitations to thermal shut-down as well as safe area protection, which makes it virtually unbreakable.
