L78L05ACD13TR – 5V 100mA Positive Linear Voltage Regulator

Product Overview

The L78L05ACD13TR is a fixed 5V positive linear voltage regulator manufactured by STMicroelectronics. It belongs to the L78L series, a family of low-current fixed output voltage regulators designed for local voltage regulation, on-card power supply stabilization, and simple low-power DC regulation circuits.

This device provides a fixed 5V output, supports up to 100mA output current, and is supplied in an SOIC-8 surface-mount package. It is commonly used in embedded control boards, sensor modules, communication devices, consumer electronics, industrial control circuits, and general-purpose 5V logic power supply designs. ST describes the L78L series as positive voltage regulators capable of delivering up to 100mA output current, with thermal overload protection, short-circuit protection, and no external components required in many basic applications. 

Part Number Breakdown

Competitive Advantages

✔ Fixed 5V positive linear regulator

✔ Up to 100mA output current

✔ Simple low-component-count design

✔ Thermal overload protection

✔ Short-circuit protection

✔ SOIC-8 surface-mount package

✔ Suitable for low-noise analog and digital supply rails

✔ Reliable STMicroelectronics L78L series technology

Key Features

1. Fixed 5V Output Regulation

The L78L05ACD13TR provides a regulated 5V output, making it suitable for powering low-current digital and analog circuits.

Benefits include:

• Simple 5V rail generation
• No output voltage divider required
• Suitable for logic circuits, sensors, and MCU support circuits
• Easy replacement for many low-current 78L05-style regulators

2. Up to 100mA Output Current

The L78L series can deliver up to 100mA output current when thermal conditions are properly managed. 

Benefits include:

• Suitable for low-power embedded circuits
• Good for bias rails, reference rails, and control electronics
• Useful for sensor modules and small analog front ends
• Compact alternative to larger 7805 regulators where current demand is low

3. Positive Linear Regulator Architecture

As a linear regulator, the L78L05ACD13TR provides clean output voltage without high-frequency switching noise.

Benefits include:

• Low-noise output compared with switching regulators
• Simple circuit design
• No inductor required
• Suitable for analog and mixed-signal circuits

4. Thermal Overload Protection

ST lists thermal overload protection as a key feature of the L78L series. 

Benefits include:

• Helps protect the regulator under excessive temperature conditions
• Improves reliability in compact designs
• Useful for fault-tolerant low-power power rails
• Reduces risk of damage during abnormal operation

5. Short-Circuit Protection

The L78L05ACD13TR includes short-circuit protection, helping protect the device and the connected circuit during fault conditions. 

Benefits include:

• Improves system robustness
• Helps protect against accidental output shorts
• Useful for development boards and field-deployed equipment
• Reduces risk of permanent damage in fault events

6. SOIC-8 Surface-Mount Package

The device is supplied in an SOIC-8 package, suitable for standard SMT manufacturing. Mouser and DigiKey both list the package as SOIC-8. 

Benefits include:

• Easy SMT assembly
• Standard footprint
• Good availability in production supply chains
• Suitable for compact PCB layouts

Applications

Embedded Control Boards

Suitable for:

• MCU control boards
• Sensor interface boards
• Small embedded modules
• Logic power rails
• Low-current peripheral circuits

Used to generate a stable 5V rail from a higher input voltage.

Industrial Control Circuits

Used in:

• PLC auxiliary circuits
• HMI control boards
• Industrial sensors
• Relay driver boards
• Automation modules

Provides local 5V regulation for control and signal-conditioning circuits.

Consumer Electronics

Applicable to:

• Set-top boxes
• Home appliances
• Small audio devices
• Display control boards
• Remote-control circuits

The simple linear regulator architecture is useful for low-power internal supply rails.

Communication and Networking Devices

Suitable for:

• Router auxiliary circuits
• Wireless modules
• Gateway devices
• Security devices
• Communication terminals

Used for low-current local regulation and bias supply generation.

Analog and Sensor Circuits

Can be used in:

• Sensor modules
• Signal-conditioning circuits
• ADC support circuits
• Reference support rails
• Low-noise analog sections

The linear regulator output is useful where switching noise must be minimized.