LM1085 Positive Regulator: Pinout, Equivalent and Circuit
Fixed 2.54mm LM1085 PMIC TO-220-3
LM1085 is a 3A low dropout positive regulator. This article mainly covers pinout, application, datasheet, circuit, and more details about the LM1085 voltage regulator. Furthermore, there is a huge range of semiconductors, capacitors, resistors, and Ics in stock. Welcome RFQ!

Buck converter vs. linear voltage regulator - practical comparison
LM1085 Pinout

LM1085 Pinout
| Pin No. | Pin Name | Description |
| 1 | ADJ/GND | Adjustable pin for adjusts output version. Ground for fixed type version |
| 2 | OUTPUT | Output Voltage Pin |
| 3 | INPUT | Input Voltage Pin |
LM1085 CAD Model
Symbol

Symbol
Footprint

Footprint
3D Model

3D Model
LM1085 Description
The LM1085 is a regulator with a maximum dropout of 1.5 V at 3 A of load current. It has the same pin-out as TI's industry-standard LM317. Two resistors are required to set the output voltage of the adjustable output voltage version of the LM1085. Fixed output voltage versions integrate the adjusted resistors.
Specifications
- TypeParameter
- Mount
In electronic components, the term "Mount" typically refers to the method or process of physically attaching or fixing a component onto a circuit board or other electronic device. This can involve soldering, adhesive bonding, or other techniques to secure the component in place. The mounting process is crucial for ensuring proper electrical connections and mechanical stability within the electronic system. Different components may have specific mounting requirements based on their size, shape, and function, and manufacturers provide guidelines for proper mounting procedures to ensure optimal performance and reliability of the electronic device.
Through Hole - Mounting Type
The "Mounting Type" in electronic components refers to the method used to attach or connect a component to a circuit board or other substrate, such as through-hole, surface-mount, or panel mount.
Through Hole - Package / Case
refers to the protective housing that encases an electronic component, providing mechanical support, electrical connections, and thermal management.
TO-220-3 - Number of Pins3
- Operating Temperature
The operating temperature is the range of ambient temperature within which a power supply, or any other electrical equipment, operate in. This ranges from a minimum operating temperature, to a peak or maximum operating temperature, outside which, the power supply may fail.
-40°C~125°C TJ - Packaging
Semiconductor package is a carrier / shell used to contain and cover one or more semiconductor components or integrated circuits. The material of the shell can be metal, plastic, glass or ceramic.
Tube - JESD-609 Code
The "JESD-609 Code" in electronic components refers to a standardized marking code that indicates the lead-free solder composition and finish of electronic components for compliance with environmental regulations.
e0 - Part Status
Parts can have many statuses as they progress through the configuration, analysis, review, and approval stages.
NRND (Last Updated: 3 days ago) - Moisture Sensitivity Level (MSL)
Moisture Sensitivity Level (MSL) is a standardized rating that indicates the susceptibility of electronic components, particularly semiconductors, to moisture-induced damage during storage and the soldering process, defining the allowable exposure time to ambient conditions before they require special handling or baking to prevent failures
1 (Unlimited) - Number of Terminations3
- ECCN Code
An ECCN (Export Control Classification Number) is an alphanumeric code used by the U.S. Bureau of Industry and Security to identify and categorize electronic components and other dual-use items that may require an export license based on their technical characteristics and potential for military use.
EAR99 - Terminal Finish
Terminal Finish refers to the surface treatment applied to the terminals or leads of electronic components to enhance their performance and longevity. It can improve solderability, corrosion resistance, and overall reliability of the connection in electronic assemblies. Common finishes include nickel, gold, and tin, each possessing distinct properties suitable for various applications. The choice of terminal finish can significantly impact the durability and effectiveness of electronic devices.
Tin/Lead (Sn/Pb) - Terminal Position
In electronic components, the term "Terminal Position" refers to the physical location of the connection points on the component where external electrical connections can be made. These connection points, known as terminals, are typically used to attach wires, leads, or other components to the main body of the electronic component. The terminal position is important for ensuring proper connectivity and functionality of the component within a circuit. It is often specified in technical datasheets or component specifications to help designers and engineers understand how to properly integrate the component into their circuit designs.
SINGLE - Number of Functions1
- Terminal Pitch
The center distance from one pole to the next.
2.54mm - Current Rating
Current rating is the maximum current that a fuse will carry for an indefinite period without too much deterioration of the fuse element.
3A - Base Part Number
The "Base Part Number" (BPN) in electronic components serves a similar purpose to the "Base Product Number." It refers to the primary identifier for a component that captures the essential characteristics shared by a group of similar components. The BPN provides a fundamental way to reference a family or series of components without specifying all the variations and specific details.
LM1085 - Number of Outputs1
- Voltage - Input (Max)
Voltage - Input (Max) is a parameter in electronic components that specifies the maximum voltage that can be safely applied to the input of the component without causing damage. This parameter is crucial for ensuring the proper functioning and longevity of the component. Exceeding the maximum input voltage can lead to electrical overstress, which may result in permanent damage or failure of the component. It is important to carefully adhere to the specified maximum input voltage to prevent any potential issues and maintain the reliability of the electronic system.
25V - Output Type
The "Output Type" parameter in electronic components refers to the type of signal or data that is produced by the component as an output. This parameter specifies the nature of the output signal, such as analog or digital, and can also include details about the voltage levels, current levels, frequency, and other characteristics of the output signal. Understanding the output type of a component is crucial for ensuring compatibility with other components in a circuit or system, as well as for determining how the output signal can be utilized or processed further. In summary, the output type parameter provides essential information about the nature of the signal that is generated by the electronic component as its output.
Fixed - Current - Output (Max)
Current - Output (Max) is a parameter in electronic components that specifies the maximum amount of current that the component can deliver at its output. This parameter is crucial in determining the capability of the component to supply power to other parts of a circuit or system. It is typically measured in amperes (A) and helps in ensuring that the component can handle the required current without getting damaged or causing malfunctions. Designers and engineers use this specification to select components that can meet the current requirements of their circuits and prevent overloading or overheating issues.
3A - Output Configuration
Output Configuration in electronic components refers to the arrangement or setup of the output pins or terminals of a device. It defines how the output signals are structured and how they interact with external circuits or devices. The output configuration can determine the functionality and compatibility of the component in a circuit design. Common types of output configurations include single-ended, differential, open-drain, and push-pull configurations, each serving different purposes and applications in electronic systems. Understanding the output configuration of a component is crucial for proper integration and operation within a circuit.
Positive - Quiescent Current
The quiescent current is defined as the current level in the amplifier when it is producing an output of zero.
5mA - Voltage - Output
Voltage - Output is a parameter that refers to the electrical potential difference between the output terminal or pin of an electronic component and a reference point, typically ground. It indicates the level of voltage that the component is capable of providing at its output under specified operating conditions. This parameter is crucial in determining the performance and functionality of the component in a circuit, as it directly affects the signal or power being delivered to other components or devices connected to the output. Engineers and designers use the voltage output specification to ensure compatibility and proper functioning of the component within the overall system.
5V - Output Voltage 1
Output Voltage 1 is a parameter commonly found in electronic components such as voltage regulators, power supplies, and amplifiers. It refers to the voltage level that is produced or delivered by the component at a specific output terminal or pin. This parameter is crucial for determining the performance and functionality of the component in a circuit. The specified output voltage should meet the requirements of the connected devices or components to ensure proper operation and compatibility. It is important to carefully consider and verify the output voltage 1 specification when selecting and using electronic components in a design or application.
5V - Number of Regulators
A regulator is a mechanism or device that controls something such as pressure, temperature, or fluid flow. The voltage regulator keeps the power level stabilized. A regulator is a mechanism or device that controls something such as pressure, temperature, or fluid flow.
1 - Min Input Voltage
The parameter "Min Input Voltage" in electronic components refers to the minimum voltage level that must be applied to the component for it to operate within its specified parameters. This value is crucial as providing a voltage below this minimum threshold may result in the component malfunctioning or not functioning at all. It is important to adhere to the specified minimum input voltage to ensure the proper operation and longevity of the electronic component. Failure to meet this requirement may lead to potential damage to the component or the overall system in which it is used.
2.6V - Protection Features
Protection features in electronic components refer to the built-in mechanisms or functionalities designed to safeguard the component and the overall system from various external factors or internal faults. These features are crucial for ensuring the reliability, longevity, and safety of the electronic device. Common protection features include overvoltage protection, overcurrent protection, reverse polarity protection, thermal protection, and short-circuit protection. By activating these features when necessary, the electronic component can prevent damage, malfunctions, or hazards that may arise from abnormal operating conditions or unforeseen events. Overall, protection features play a vital role in enhancing the robustness and resilience of electronic components in diverse applications.
Over Current, Over Temperature - Current - Quiescent (Iq)
The parameter "Current - Quiescent (Iq)" in electronic components refers to the amount of current consumed by a device when it is in a quiescent or idle state, meaning when it is not actively performing any tasks or operations. This parameter is important because it represents the baseline power consumption of the device even when it is not actively being used. A lower quiescent current (Iq) value is desirable as it indicates that the device is more energy-efficient and will consume less power when not in use, which can help extend battery life in portable devices and reduce overall power consumption in electronic systems. Designers often pay close attention to the quiescent current specification when selecting components for low-power applications or battery-operated devices.
10mA - Voltage Dropout (Max)
Voltage Dropout (Max) refers to the minimum voltage difference between the input and output of a voltage regulator or linear power supply needed to maintain proper regulation. It indicates the maximum allowable voltage drop across the device for it to function effectively without dropout. If the input voltage falls below this threshold, the output voltage may drop below the specified level, leading to potential operational issues for connected components. This parameter is critical for ensuring stable and reliable power delivery in electronic circuits.
1.5V @ 3A - PSRR
PSRR stands for Power Supply Rejection Ratio. It is a measure of how well a device, such as an amplifier or a voltage regulator, can reject variations in the power supply voltage. A high PSRR value indicates that the device is able to maintain its performance even when the power supply voltage fluctuates. This parameter is important in ensuring stable and reliable operation of electronic components, especially in applications where the power supply voltage may not be perfectly regulated. A good PSRR helps to minimize noise and interference in the output signal of the device.
68dB (120Hz) - Dropout Voltage
Dropout voltage is the input-to-output differential voltage at which the circuit ceases to regulate against further reductions in input voltage; this point occurs when the input voltage approaches the output voltage.
1.3V - Dropout Voltage1-Nom
Dropout Voltage1-Nom is a parameter commonly found in voltage regulators and power management ICs. It refers to the minimum voltage difference required between the input voltage and the output voltage for the regulator to maintain regulation. In other words, it is the minimum voltage drop that the regulator can handle while still providing a stable output voltage. This parameter is important to consider when designing power supply circuits to ensure that the regulator can operate within its specified voltage range and maintain proper regulation under varying load conditions.
1.3V - Voltage Tolerance-Max
Voltage Tolerance-Max is a parameter in electronic components that specifies the maximum allowable deviation from the rated voltage without causing damage or malfunction. It indicates the range within which the component can safely operate without being affected by voltage fluctuations. This parameter is crucial for ensuring the reliability and longevity of the component in various electrical systems. Manufacturers provide this specification to help users understand the limits within which the component can function properly and to prevent potential failures due to overvoltage conditions.
2% - Min Current Limit
Min Current Limit is a parameter in electronic components that refers to the minimum amount of current that must flow through the component to ensure proper operation. This parameter is important because if the current falls below this limit, the component may not function as intended or may even be damaged. Manufacturers specify the minimum current limit to help users understand the operating conditions and limitations of the component. It is crucial to ensure that the current flowing through the component remains above the specified minimum limit to maintain its performance and reliability.
3.2A - Height4.7mm
- Length14.986mm
- Width10.16mm
- Thickness
Thickness in electronic components refers to the measurement of how thick a particular material or layer is within the component structure. It can pertain to various aspects, such as the thickness of a substrate, a dielectric layer, or conductive traces. This parameter is crucial as it impacts the electrical, mechanical, and thermal properties of the component, influencing its performance and reliability in electronic circuits.
4.572mm - Radiation Hardening
Radiation hardening is the process of making electronic components and circuits resistant to damage or malfunction caused by high levels of ionizing radiation, especially for environments in outer space (especially beyond the low Earth orbit), around nuclear reactors and particle accelerators, or during nuclear accidents or nuclear warfare.
No - RoHS Status
RoHS means “Restriction of Certain Hazardous Substances” in the “Hazardous Substances Directive” in electrical and electronic equipment.
Non-RoHS Compliant - Lead Free
Lead Free is a term used to describe electronic components that do not contain lead as part of their composition. Lead is a toxic material that can have harmful effects on human health and the environment, so the electronics industry has been moving towards lead-free components to reduce these risks. Lead-free components are typically made using alternative materials such as silver, copper, and tin. Manufacturers must comply with regulations such as the Restriction of Hazardous Substances (RoHS) directive to ensure that their products are lead-free and environmentally friendly.
Contains Lead
LM1085 Block Diagram

LM1085 Block Diagram
LM1085 Features
Available in 3.3V, 5.0V, 12V, and Adjustable Versions
Current Limiting and Thermal Protection
Output Current 3A
Line Regulation 0.015% (typical)
Load Regulation 0.1% (typical)
LM1085 Applications
High-Efficiency Linear Regulators
Battery Charger
Post Regulation for Switching Supplies
Constant Current Regulator
Microprocessor Supply
Where to use LM1085
The LM1085 has a wide range of applications. This device can be used for programmable output regulation as well as local on-card regulation. By putting a set resistor between the adjust and output pins, it can be used as a precision current regulator. It is quite difficult to attain a high ripple-rejection ratio in other standard three-terminal regulators. However, the chip's adjust pin can be ignored, resulting in a high rejection ratio.
How to use LM1085
The LM1085 is available in three versions, two of which have a set regulated output and one of which is an adjustable regulator. This LM1085 is in adjustable mode, as shown in the image below, and you can alter the regulated output voltage by adjusting the value of resistors R1 and R2.

LM1085 Application Circuit
LM1085 Equivalent
LM1084, LM317, LM723, LM7912
Parts with Similar Specs
- ImagePart NumberManufacturerPackage / CaseNumber of PinsNumber of OutputsMax Output CurrentMin Input VoltageVoltage - Input (Max)Output VoltageDropout VoltageView Compare
LM1085IT-5.0
TO-220-3
3
1
3 A
2.6 V
25V
5 V
1.3 V
TO-220-3
3
1
5 A
2.6 V
25V
5 V
1.3 V
TO-220-3
3
1
5 A
2.6 V
27V
3.3 V
1.3 V
TO-220-3
3
1
1.5 A
2.6 V
25V
5 V
1.3 V
LM1085 Package


LM1085 Package
LM1085 Manufacturer
Texas Instruments (TI) is a global semiconductor firm originating in 1958 and nowadays it has over 30,000 employees who design, conduct, and sell analog and product-differentiating embedded processing components in 35 countries. Aimed at changing the world of tech, TI has put great effort into becoming the solution provider coupled with a vision.
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Datasheet PDF
- Datasheets :
- PCN Assembly/Origin :
How does LM1085 work?
The LM1085 series develops a 1.25V reference voltage between the output and the adjusted terminal. Placing a resistor between these two terminals causes a constant current to flow through R1 and down through R2 to set the overall output voltage. This current is normally the specified minimum load current of 10mA.
What kind of tube can be used for LM1085?
You can use LM317 instead. You may pay attention to that you need to adjust the output voltage of LM317 to 3.3 volts. LM317 is one of the most widely used power supply integrated circuits. It not only has the simplest form of a fixed three-terminal voltage regulator circuit but also has the characteristics of adjustable output voltage.
What is the voltage of the three pins and how to judge its quality?
LM1085 is a three-terminal voltage regulator device with low dropout voltage. It is good to connect the power supply and change the current or input voltage flowing through it, as long as its output voltage is basically unchanged.
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