78L05-LDO5V Linear Voltage Regulator TO-92

78L05-LDO5V Linear Voltage Regulator TO-92 is a reliable, three-terminal positive voltage regulator that delivers a highly stable 5V output for low-current applications. The ‘L’ series offers a compact and cost-effective solution compared to its larger 7805 counterpart. Consequently, designers select this device for space-constrained electronics that require a precise, fixed voltage source. With built-in current limiting and thermal shutdown protection, the 78L05 effectively safeguards both itself and the downstream components from accidental damage. Furthermore, its small TO-92 package allows for convenient through-hole mounting on standard PCBs, making it a staple component in consumer electronics and hobbyist projects globally.

Key Features:

• Fixed Output Voltage: Delivers a non-adjustable, highly accurate output of 5.0 V (±5% tolerance) without requiring external resistors.
• Integrated Protection: The device includes internal thermal overload protection and short-circuit current limiting, which enhances system reliability.
• Low Quiescent Current: Operates efficiently with minimal current draw when no load is present, conserving power in battery-operated circuits.
• Standard TO-92 Package: The ubiquitous, compact plastic casing facilitates easy handling and standard through-hole mounting on circuit boards.
• Low-Current Capability: Provides sufficient current for powering logic ICs (TTL/CMOS), small microcontrollers, and low-power sensor circuits.

Technical Specifications:

• Nominal Output Voltage (V_O): 5.0 V
• Output Current (I_O): 100 mA (Up to 200 mA peak with adequate cooling)
• Input Voltage Range (V_IN): 7 V to 20 V DC
• Quiescent Current (I_Q): Typically 3.5 mA
• Line Regulation: Typically 3 mV
• Load Regulation: Typically 10 mV
• Dropout Voltage: ≈ 1.7 V (Ensures regulation when V_IN is close to V_O)
• Operating Junction Temperature: 0°C to +125°C

Mechanical Specifications:

• Package Style: TO-92 (Transistor Outline, small plastic)
• Mounting: Through-Hole Technology (THT)
• Pin Material: Tinned Copper or Copper Alloy
• Heat Dissipation: Uses the PCB traces and surrounding air for heat sinking (adequate cooling is critical for currents ≥ 100 mA).

Dimensions:

• Body Height: ≈ 4.5 mm (Excluding leads)
• Body Width (Diameter): ≈ 4.8 mm
• Pin Spacing (E-C-B pitch): 1.27 mm (Standard TO-92 pitch)
• Lead Length: ≈ 14 mm (Can be trimmed as needed)
• Weight: ≈ 0.2 g (Minimal impact on portable device weight)

Pinout and Wiring:

• Pin 1 (Output): Connect this pin to the circuit load requiring the regulated +5V supply.
• Pin 2 (Ground / Common): Connect the center pin to the circuit ground (0 V).
• Pin 3 (Input): Connect this pin to the unregulated DC input voltage (must be V_IN ≥ 7 V).
• Wiring Note: We highly recommend placing small ceramic capacitors (e.g., 0.1 μF) between Pin 3 and GND, and Pin 1 and GND, to ensure stability and reduce high-frequency noise.

Datasheet Reference:

• Download STMicroelectronics 78L05 Datasheet (LM78L05 equivalent)

Commonly Used in:

• Microcontroller Circuits: Providing the primary power source for most 5V CMOS and TTL logic ICs.
• Sensor Power Supplies: Regulating voltage for small digital and analog sensors that require a stable 5V reference.
• USB-Powered Devices: Often used as a secondary regulator to clean up and step down the 5V USB line for internal circuits.

Applications:

• Embedded Systems: Powering low-power boards, educational kits, and small IoT devices.
• DIY Electronics Projects: Providing a simple, fixed 5V rail for breadboarding and prototyping circuits.
• Power Filtering: Using it to regulate an already-filtered but slightly higher voltage to achieve a precise 5V output.

Equivalent Models:

• LM78L05ACZ: A widely used equivalent from different manufacturers like ON Semi and Texas Instruments, offering identical functionality.
• KA78L05A: The part number often used by Fairchild (now ON Semi) for the same 5V/100mA regulator in a TO-92 package.
• L78L05ACZ (ST): STMicroelectronics’ designation for this specific regulator series. However, always verify the exact package (TO-92) when selecting a cross-reference.

Package Includes:

• 1 x 78L05-LDO5V Linear Voltage Regulator TO-92