LM1117 3.3V Low Dropout Voltage Regulator TO-220

LM1117 3.3V Low Dropout Voltage Regulator TO-220 is a high-performance positive voltage regulator designed to provide a stable 3.3 V output with a significantly low dropout voltage of just 1.2 V at 800 mA of load current. This component offers an ideal solution for modern electronics that require efficient power management and precise voltage regulation from a higher input source. Furthermore, the device incorporates internal current limiting and thermal protection to ensure long-term reliability even under strenuous operating conditions. Consequently, it has become a staple for engineers building battery-powered devices and logic circuits where minimizing power loss is critical. Therefore, you can rely on the LM1117 to maintain a steady 3.3 V rail for your most sensitive microcontrollers and sensors.

Key Features:

• Low Dropout Performance: The device maintains regulation even when the input voltage is only 1.2 V above the output, maximizing efficiency.
• High Output Current: It safely delivers up to 800 mA of continuous current, making it suitable for powering wireless modules and small displays.
• Thermal Overload Protection: Built-in circuitry automatically shuts down the regulator if the junction temperature exceeds safe limits.
• Short Circuit Current Limiting: The IC prevents damage during fault conditions by restricting the output current to a safe maximum level.
• Excellent Line and Load Regulation: This regulator ensures a consistent output voltage regardless of fluctuations in the input supply or changes in the connected load.

Technical Specifications:

• Output Voltage: Fixed 3.3 V
• Maximum Input Voltage: 15 V
• Maximum Output Current: 800 mA
• Dropout Voltage (Typical): 1.2 V at 800 mA
• Line Regulation: 0.2% Maximum
• Load Regulation: 0.4% Maximum
• Operating Junction Temperature: 0°C to +125°C
• Quiescent Current: ≈ 5 mA

Mechanical Specifications:

• Package Type: TO-220-3 (Through-Hole)
• Case Material: Molded Plastic with Metal Heat Sink Tab
• Lead Finish: Matte Tin
• Thermal Resistance (Junction to Case): ≈ 3.0 °C/W

Dimensions:

• Body Height: ≈ 9.15 mm
• Body Width: ≈ 10.15 mm
• Tab Height: ≈ 6.35 mm
• Lead Pitch: 2.54 mm (Standard 0.1 inch)
• Total Length (Body + Leads): ≈ 28.5 mm

Pinout and Wiring:

• Pin 1 (ADJ/GND): Connect this pin to the circuit ground for the fixed 3.3 V version.
• Pin 2 (Output): This pin provides the regulated 3.3 V signal to your load. However, the metal tab is also electrically connected to this pin.
• Pin 3 (Input): Connect the unregulated input voltage (typically 4.5 V to 12 V) to this terminal.
• Capacitor Requirement: Always place a 10 μF tantalum capacitor on the output pin to ensure frequency stability and prevent oscillation.

Datasheet Reference:

• Download Texas Instruments LM1117 Datasheet

Commonly Used in:

• Post Regulators: Frequently used after a 5 V switching regulator to provide a clean 3.3 V rail for digital logic.
• Battery Chargers: Integrated into low-current charging circuits for lithium-based battery packs.
• Computer Motherboards: Managing local voltage regulation for high-speed bus terminators and auxiliary chips.

Applications:

• Microcontroller Power: Providing a stable voltage source for ESP8266, ESP32, and ARM Cortex-M microcontrollers.
• Consumer Electronics: Regulating power in portable music players, set-top boxes, and DVD players.
• Industrial Instrumentation: Ensuring precise voltage for signal conditioning circuits and data loggers.

Equivalent Models:

• AMS1117-3.3: A very popular and widely available alternative, although it is more commonly found in SMT packages.
• LD1117V33: The STMicroelectronics version which offers identical pinouts and electrical characteristics in the TO-220 package.
• NCP1117: An ON Semiconductor equivalent that serves as a high-quality drop-in replacement for the LM1117 series.

Package Includes:

• 1 x LM1117 3.3V Low Dropout Voltage Regulator TO-220