LM7805 IC is a three pinout voltage regulator IC that belongs to the family of LM78**. In this post, we will talk about its pin configuration, features, applications equivalent ICs, and much more information you need to know about LM7805 ICs.
LM7805 ICs Features & Specifications.
- TO-220 package type IC.
- Fix output voltage of 5V.
- It’s output current is 1.5mA.
- It has instant short circuit shutdown function.
- It has instant overheat shutdown functions.
- low quiescent current of only 8mA.
- it maximum input voltage is 35V DC.
- Low cost.
LM7805 IC Pinout & Explanation.
The table below contains the pins of the LM7805 regulator IC, function of the pin and where to connect the pins.
| No. | PINs | Function | Description |
| 1 | Input | Input Voltage(7V-35V) | Here is where the positive unregulated Voltage to be regulated is feed on. |
| 2 | Ground | Ground(0V) | The is the neural pin of the IC. It is connected to the neutral point on the circuit. |
| 3 | Output | Output(5V) | This is where the regulated 5V is taken from. The voltage at this point is stable. |
From the above table, You might have noticed that the input voltage of the IC can range from 7V – 37V while the output voltage is 5V. You might be wondering where the remaining voltage is stored whereas LM7805 IC is not an energy storage component. The IC releases the difference between the input voltage and output voltage as heat. The greater the input voltage the more the IC heats up.
The LM7805 IC is always connected to a heat sink to dissipate the heat coming out from the IC during operation. So the LM7805 is fixed on a heat sink to protect the IC from burning due to high temperature.
It is more advisable to limit the input voltage of the IC to 2-3 Voltage higher than output voltage. This is to reduce the dissipated heat from the IC.
So during the circuit design using LM7805, make the input voltage 2-3V higher than the output 5V. But when that option is not achievable then, consider using a heatsink to cool off the IC heat.
7805 IC heating problems & calculations.
The problem associated with 7805 IC is the voltage drop and energy waste in the form of heat. So when planning to make use of this IC on your project consider using an appropriate heatsink that can dissipate the heat. The formula below are used in calculating right size of heat sink to use with the IC.
Heat generated = (input Voltage – 5V) × output current.
Let say we feed in 7805 IC with 15V at the input and the output Current is 0.5A.
Then using the above formula, it should be;
(15V-5V) × 0.5 = 10 × 0.5 = 5W.
As we can see 5W energy is wasted through heat while the utilized energy is (5 × 0.5) = 2.5W. Like twice of the output energy is wasted through heat. The 5W energy can cause damage to the IC or make it malfunction when it is not fixed to the appropriate heatsink.
Let try reducing the input voltage to see what we can achieve and energy wasted.
Suppose 9V is being fed to the IC input, with the same amount of load, then we will have, (9V-5V) × 0.5 = 2W.
2W of energy is what will be dissipated through heat. Just like what we said earlier, always reduces the input voltage to 2- 3 V of the output to reduce energy loose through heat on the IC.
LM7805 Description and Explanation.
In electronic circuits, we always try as much as possible to keep our voltage signal stable and avoid fluctuations. LM7805 IC is a +5V output regulator IC that gives out a stable +5V DC not minding the input voltage. Is one of the positive regulator ICs from the LM78** series. Other ICs from the same series are LM7806, LM7808, LM7812, LM7815, LM7824 and others
With the LM7805 IC coupled with other components, we can be able to rectify an AC and achieve a good stabilized +5V DC.
The LM7805 is in TO-220 and other packages. It has many good features that make it widely used on electronics both for commercial equipment and student projects.
LM7805 Equivalent or replacements.
LM3050, LM3040A, and LM1084-5.0 are ICs which can be used in place of LM7805. The following ICs give out fixed positive 5V DC.
Applications.
- Voltage Regulator ccircuit.
- Motor driver circuit.
- Voltage stepdown
- battery charger circuits.
- Solar power supply.
- Current regulator
- Reverse bias projection Circuit
How to safely long run the LM7805 ICs in a circuit.
Do the following for the long-term performance of these ICs.
- Make sure the operational load of the IC is not above 1.5mA.
- Always use a suitable heat sink on the IC to cool it during operation.
- It should not be operated on temperatures below 0°C and above +125°C.
LM7805 Datasheet.
Copy and paste the below URL on your browser to download the LM7805 IC datasheet.
