AMS1117 3.3V 1A LDO Voltage Regulator SOT-223

AMS1117 3.3V 1A LDO Voltage Regulator SOT-223 is an indispensable component for embedded systems and low-voltage digital circuits that demand a stable and precise 3.3 V power supply. This Low-Dropout (LDO) linear regulator efficiently converts higher input voltages (typically 4.75 V to 15 V) down to the required 3.3 V output. Consequently, it provides a cost-effective and compact solution for powering sensitive logic ICs, microcontrollers, and wireless modules. Furthermore, its low dropout voltage minimizes power loss, making it highly suitable for battery-powered devices where maximizing efficiency is critical. The SOT-223 surface-mount package allows for simple integration into densely packed PCBs, ensuring reliable performance across a broad range of consumer and industrial electronics.

Key Features:

• Fixed 3.3 V Output: The AMS1117-3.3 provides a regulated output voltage of 3.3 V with high precision, eliminating the need for external setting resistors.
• Low Dropout Voltage (LDO): This regulator features a dropout voltage typically below 1.3 V at maximum load, meaning it maintains regulation even when the input voltage is close to the output voltage.
• High Output Current: It delivers a guaranteed output current capability of 1 A, readily supporting most small to medium-sized embedded projects.
• Current and Thermal Limiting: Built-in circuitry provides essential protection against both excessive output current and high junction temperatures, increasing device reliability.
• Surface Mount Package: The compact SOT-223 package simplifies assembly and saves significant space on modern Printed Circuit Boards (PCBs).

Technical Specifications:

• Output Voltage (V_OUT): 3.3 V (±1.5% accuracy)
• Maximum Output Current (I_OUT): 1 A
• Input Voltage Range (V_IN): 4.75 V to 15 V (Maximum 18 V absolute)
• Dropout Voltage (V_DO): 1.1 V (Typ. @ 1 A) to 1.3 V (Max. @ 1 A)
• Quiescent Current (I_Q): 10 mA (Typ.)
• Line Regulation: 0.2% (Max.)
• Operating Junction Temperature Range: 0°C to +125°C

Mechanical Specifications:

• Package Type: SOT-223 (Small Outline Transistor)
• Mounting: Surface Mount Device (SMD/SMT)
• Power Dissipation: Dependent on the PCB copper area; therefore, design adequate heat sinking into the board.
• Moisture Sensitivity Level (MSL): MSL 1 (Generally suitable for unlimited floor life after opening)

Dimensions:

• Body Length: ≈ 6.5 mm
• Body Width: ≈ 3.5 mm
• Height: ≈ 1.6 mm
• Pin Pitch: 2.3 mm (Between pins 1 & 2) and 4.6 mm (Between pin 2 & 3)
• Thermal Pad Size: The large tab serves as the primary heat dissipation surface.

Pinout and Wiring:

• Pin 1 (GND / Adjust): Connect the ground pin directly to the circuit ground (0 V).
• Pin 2 (V_OUT): This pin provides the regulated 3.3 V output voltage. Connect an output capacitor (typically 10 μF Tantalum or Ceramic) between this pin and GND.
• Pin 3 (V_IN): Connect the unregulated DC input voltage (V_IN ≥ 4.75 V) to this pin.
• Thermal Pad: Solder the exposed pad on the back to a large copper area on the PCB; in fact, this greatly enhances thermal performance.

Datasheet Reference:

• Download AMS1117 Series Voltage Regulator Datasheet

Commonly Used in:

• Microcontroller Boards: Supplying 3.3 V to core ICs like ESP32, STM32, and low-power AVR microcontrollers.
• Wireless Communication: Powering 3.3 V Wi-Fi, Bluetooth, and Zigbee modules (e.g., ESP8266, NRF24L01).
• Digital Signal Processing (DSP): Generating a clean 3.3 V rail for digital logic components.

Applications:

• Post-Regulation: Stepping down the output of a switching power supply to reduce ripple and noise.
• Level Shifting: Creating a stable 3.3 V domain from a 5 V or 12 V source to interface different logic levels.
• Battery-Powered Devices: Maximizing battery life by using the LDO feature to regulate until the battery voltage drops close to the required 3.3 V.
• FPGA and CPLD Power Supplies: Providing dedicated, clean power rails for core logic.

Equivalent Models:

• LM1117-3.3: The original National Semiconductor/Texas Instruments version, hence it is the most common functional equivalent.
• NCP1117ST33T3G (Onsemi): A direct cross-reference part providing identical voltage and current specifications in the SOT-223 package.
• LD1117S33TR (STMicroelectronics): Another widely available LDO with the same 3.3 V fixed output and 1 A capability.

Package Includes:

• 1 x AMS1117 3.3V 1A LDO Voltage Regulator SOT-223