LM1117T Low Dropout Voltage Regulator

Overview

The LM1117T is a low dropout (LDO) voltage regulator designed to provide a stable output voltage with a minimal input-to-output voltage differential. It is part of the LM1117 series, which is widely recognized for its reliability and performance in various electronic applications. The LM1117T is particularly noted for its ability to deliver up to 800mA of load current with a dropout voltage of just 1.2V, making it an efficient choice for power-sensitive designs.

This regulator is pin-compatible with the industry-standard LM317, allowing for easy replacement or upgrades in existing designs. The LM1117T is available in both adjustable and fixed output voltage versions, providing flexibility for a wide range of applications.

Features

• Low Dropout Voltage: 1.2V at 800mA load current, ensuring efficient operation even with low input voltages.
• High Output Current: Capable of delivering up to 800mA, suitable for powering a variety of loads.
• Adjustable and Fixed Output Versions: Available in fixed output voltages of 1.8V, 2.5V, 2.85V, 3.3V, and 5V, as well as an adjustable version (1.25V to 13.8V).
• Pin-Compatible with LM317: Easy drop-in replacement for designs using the LM317 regulator.
• Thermal Overload Protection: Built-in protection to prevent damage from excessive heat.
• Current Limit Protection: Safeguards the regulator and connected components from overcurrent conditions.
• Stable with Low-ESR Capacitors: Designed to work with low-ESR capacitors, reducing the need for additional components.

Applications

The LM1117T is versatile and can be used in a wide range of applications, including but not limited to:

• Consumer Electronics: Power supplies for portable devices, audio equipment, and gaming consoles.
• Industrial Systems: Voltage regulation for control systems, sensors, and automation equipment.
• Telecommunications: Power management in routers, modems, and other communication devices.
• Automotive Electronics: Stable voltage supply for infotainment systems, navigation units, and lighting controls.
• Embedded Systems: Microcontroller and FPGA power supplies in development boards and prototyping environments.
• Battery-Powered Devices: Efficient voltage regulation for handheld and portable battery-operated equipment.

Electrical Characteristics

The following table summarizes the key electrical specifications of the LM1117T under typical operating conditions (unless otherwise noted):

Absolute Maximum Ratings

• Input Voltage (V_IN): 15V
• Output Voltage (V_OUT): Adjustable version: 1.25V to 13.8V; Fixed versions: as specified (1.8V, 2.5V, 2.85V, 3.3V, 5V)
• Output Current (I_OUT): 800mA (maximum)
• Operating Junction Temperature (T_J): -40°C to +125°C
• Storage Temperature (T_STG): -65°C to +150°C

Typical Performance Characteristics

• Dropout Voltage: 1.2V (at 800mA load current)
• Line Regulation: 0.2% (typical)
• Load Regulation: 0.4% (typical)
• Quiescent Current: 5mA (typical)
• Ripple Rejection: 75dB (typical at 1kHz)

Package Information

The LM1117T is available in a TO-220 package, which is a through-hole mounting style with excellent thermal performance. The package dimensions and pin configuration are as follows:

TO-220 Package Dimensions

• Package Type: TO-220 (3-pin)
• Length: 10.16mm (0.4 inches)
• Width: 4.57mm (0.18 inches)
• Height: 9.15mm (0.36 inches)
• Lead Pitch: 2.54mm (0.1 inches)

Pin Configuration

• Pin 1 (Adjust/Ground): For adjustable versions, this pin is used to set the output voltage via an external resistor divider. For fixed versions, this pin is connected to ground.
• Pin 2 (Output): The regulated output voltage.
• Pin 3 (Input): Unregulated input voltage supply.

Conclusion

The LM1117T is a highly reliable and efficient low dropout voltage regulator suitable for a broad range of applications. Its combination of low dropout voltage, high output current capability, and thermal protection makes it an excellent choice for both consumer and industrial electronics. The availability of fixed and adjustable output versions further enhances its versatility, allowing designers to tailor the regulator to their specific needs. With its robust TO-220 package and industry-standard pinout, the LM1117T is a dependable solution for power regulation challenges.