A positive voltage regulator IC is an electronic component that maintains the output voltage stable instead of changes within the input voltage (or) load. So it is a key component in many electronic circuits and devices. This positive voltage regulator is used in almost all types of electronic circuits & devices. So LM1084 IC is a low dropout positive voltage regulator IC designed by Texas Instruments and revised in Jan 2015. This article elaborates on LM1084 IC, pin-out, specifications, and its applications
What is the LM1084 IC?
LM1084 IC is a low dropout positive voltage regulator that provides a stable and regulated output voltage with up to 5A high current capabilities. This voltage regulator has a low dropout voltage that regulates output even when the input voltage is slightly higher than the desired output. This makes it appropriate for applications where efficiency and least power loss are necessary like powering sensitive electronic components within embedded systems, computer peripherals & communication devices.
This regulator has thermal shutdown & current limiting features to protect from overheating & excessive current. This IC can also support fixed and adjustable output voltage options which allows flexibility in its use. This IC is a reliable choice for delivering constant power in different electronic applications due to its low dropout characteristics & robust performance.
How LM1084 IC Work?
The LM1084 IC works as a positive voltage regulator that delivers a stable output voltage at up to 5A high current with a low voltage drop. So, it maintains a stable output voltage even when the input voltage is somewhat higher than the desired output voltage. This IC can be configured for either adjustable or fixed output voltage with external resistors, depending on the preferred version.
It operates with a very small variation between the input & the output voltages which makes it perfect for situations where battery voltage might fluctuate. So the adjustable version type allows you to set the preferred output voltage with a resistor divider network, connected between the two adjust & the output pins.
The LM1084 IC features prevent IC damage from overheating or excessive current draw like current limiting & thermal shutdown. So this IC has an internal voltage reference that works as a stable reference point mainly for adjusting the output voltage.
So the output voltage is monitored constantly through a feedback loop, and any variations from the preferred voltage are adjusted through the internal circuitry to keep stability. This IC utilizes a high-current pass transistor that regulates the flowing current throughout the circuit.
LM1084 IC Pin Configuration:
The LM1084 IC pin configuration is shown below. This IC includes three pins which are explained below.
LM1084 IC Pin Configuration
- Pin-1 (ADJ/GND): ADJ pin is connected to two resistors in variable voltage case or else connected to GND in fixed voltage case.
- Pin-2 (Output): It is an output voltage pin of IC.
- Pin-3 (INPUT): It is an input voltage pin of the regulator IC.
Features & Specifications:
The features and specifications of LM1084 IC include the following.
- It is a low drop-out positive voltage regulator.
- It is available in TO-263 & TO-220 packages.
- It provides 3.3V to 5V fixed and 0V to 29V adjustable voltage.
- Its output voltage is 5A.
- The load regulation is 0.015% and the line regulation is 0.1%.
- Its ripple rejection is 75 dB.
- This IC has thermal protection, internal current limiting & Zener-trimmed bandgap reference functions.
- It is available in 3.3V, 5.0V & adjustable versions.
- It has thermal protection & current limiting.
- Industrial temperature ranges from −40˚C to 125˚C
- Its operating temperature ranges from -65 °C to 150 °C.
Equivalent & Alternative ICs
Equivalent LM1084 ICs are; LM1085 IC and LM1086 IC. Alternative positive voltage regulators are; LM7805 IC, LM7815 IC, LM7808 IC, LM7508 IC, etc.
3Amps 15 Volt RPS Circuit with LM1084 IC
3Amps 15V RPS circuit is used in different industrial and academic circuits. So these DC supplies offer an easy way of testing & troubleshooting different equipment and electronic projects. Here we are going to make a simple 15V 3A RPS circuit with LM1084 regulator IC.
A Positive LM1084 voltage regulator IC has a low drop voltage at a higher current value. So the highest voltage drop by this regulator IC at 5Amps of load current will be 1.5Volts. The regulated output voltage can be adjusted with two resistors. This IC is available with an incorporated Zener diode for thermal shutdown and current limiting purposes.
The required components to make this circuit mainly include LM1084 voltage regulator IC, 0.1uF ceramic capacitor, 1N4007 Diode, 4.7K potentiometer, Heat sink, 2200μF/25V, 47μF/25V electrolytic capacitors, rail connectors, 1.5K resistors, breadboard, and connecting wires. Connect this circuit as per the diagram shown below.
3Amps 15 Volt RPS Circuit with LM1084 IC
Working
This circuit uses an LM1084 positive low dropout voltage regulator chip. So 18V AC/DC low dropout input voltage is provided to a bridge rectifier which converts AC to rippling DC. After that, this signal goes through a 2200uF/25V C1 smoothing capacitor to eliminate any residual noise.
The LM1084 voltage regulator IC generates a 15V/3A stable signal. So this signal can be tuned by simply connecting a 4.7K potentiometer across the OUT & ADJ pins of the IC. After that, DC signal supplies through 0.1uF & 47uF/25V smoothing capacitors. Finally, the output can be obtained by a rail connector.
Generally, DC power supplies are used widely in low voltage-based applications like battery charging, trainer or test bench support, and automotive applications.
Advantages & Disadvantages
The advantages of LM1084 IC include the following.
- This is a low dropout positive voltage regulator that provides a stable & regulated output voltage with up to 5 amps high current abilities.
- It has a low dropout voltage, so it can change output even when the input voltage is only somewhat higher as compared to the preferred output.
- It has a high ripple-rejection ratio.
- This IC can be used within local on-card regulation, programmable output regulation, etc.
- This IC includes thermal shutdown and current limiting features
- It can operate from −40°C to 125°C temperature range.
- It is a high-efficiency linear regulator
- This IC has an intrinsically lower quiescent current.
The disadvantages of LM1084 IC include the following.
- The LM1084 IC can be broken by ESD.
- It will not function as a negative regulator from a negative i/p voltage.
- It has a huge loss & the efficiency is poor whenever there is a huge variation between the two voltages.
- This IC can heat up whenever in operation.
Applications
The applications of LM1084 IC include the following.
- The LM1084 IC is used to design battery charger circuits.
- It can be used as a linear regulator due to its high efficiency.
- It is used as a post regulator for switching DC/DC converters.
- LM1084 IC is used in low-voltage microprocessor applications due to fast transient response and low dropout voltage.
- Used as a post regulator in DC to DC converters.
- The LM1084 IC is used in local on-card regulation & programmable output regulation.
- These are used widely in low voltage applications like automotive applications, charging batteries, trainer and test bench support applications.
- This versatile IC is used in local on-card regulation & programmable output regulation.
- It works like a precision current regulator through a fixed resistor, connected between the adjust pin & output pins.
- This IC can be used as a post regulator within DC-to-DC switching converters.
- This IC can be used as a linear regulator due to its high efficiency.
Please refer to this link for the LM1084 IC Datasheet.
Thus, this is an overview of LM1084 IC, features, specifications, working, pros, cons, and applications. This is a low dropout voltage regulator with 1.5V a maximum dropout at 5Amps of load current. It is accessible in an adjustable version that can set the o/p voltage using two external resistors. So it has a current limiting, thermal shutdown & Zener trimmed band-gap reference. Here is a question for you, what is LDO?