2pcs ams1117 3.3v

🔹 2PCS AMS1117-3.3 – 800mA Low Dropout 3.3V Voltage Regulator

A compact, fixed-output, low dropout (LDO) linear voltage regulator IC providing a stable 3.3V DC output from a higher input voltage (up to 15V). The AMS1117 series is a popular and cost-effective replacement for the older LM1117, ideal for powering 3.3V microcontrollers, sensors, and digital circuits.

✅ Specifications:

• Part Number: AMS1117-3.3 (Fixed 3.3V output variant)

• Type: Low Dropout (LDO) Linear Voltage Regulator

• Output Voltage: Fixed 3.3V (±1% typical accuracy)

• Output Current: Up to 800mA (with adequate heatsinking)

• Input Voltage Range: 4.3V to 15V (Absolute maximum: 20V)

• Dropout Voltage: ~1.1V at 800mA load (Key LDO spec – input can be as low as ~4.4V for 3.3V output)

• Line Regulation: 0.2% (Typical)

• Load Regulation: 0.4% (Typical)

• Package: SOT-223 (Common) or TO-252 (DPAK) – Surface Mount
  Note: Often sold as a pre-soldered module with pins for through-hole use.

• Operating Temperature: -40°C to +125°C

• Protections: Internal current limit and thermal shutdown.

• Quantity: 2 pieces

⚙️ Key Features:

• Low Dropout: Can regulate 3.3V even with an input as low as ~4.4V, making it excellent for battery-powered applications (e.g., 5V down to 3.3V).

• High Current Capability: Can supply up to 800mA, sufficient for most 3.3V MCU boards (ESP8266, ESP32) and peripherals.

• Stable & Accurate Output: Tight voltage tolerance ensures reliable operation of sensitive 3.3V logic.

• Built-in Protections: Safeguards against overloads and overheating.

• Compact & Efficient: The SOT-223 package offers a good balance of size and thermal performance.

📦 Typical Applications:

• 3.3V Power Rails: Deriving a 3.3V supply from 5V USB, 7-12V wall adapters, or Li-Po batteries (1S).

• Microcontroller Power: Dedicated power supply for ESP8266, ESP32, STM32, or 3.3V Arduino boards.

• Sensor & Module Power: Powering 3.3V logic level sensors, GPS modules, and SD cards.

• Logic Level Shifting: As a clean 3.3V reference for level shifters when interfacing 5V and 3.3V devices.

• Battery-Powered Devices: Efficiently regulating voltage from a 4.2V (Li-ion) or 5V (USB) source down to 3.3V.

🔧 Basic Circuit & Usage:

1. Required External Components:

   • Input Capacitor (Cin): A 10µF electrolytic or tantalum capacitor placed close to the input pin.

   • Output Capacitor (Cout): A 22µF electrolytic or tantalum capacitor placed close to the output pin. *(The AMS1117 requires a minimum ESR on the output cap for stability—tantalum or low-ESR electrolytic is recommended.)*

2. Wiring:

   • VIN: Connect to your unregulated DC input (4.3V – 15V).

   • GND: Connect to common ground.

   • VOUT: Provides regulated 3.3V output.

3. Heatsinking: For currents above ~200mA or with a high input-output voltage differential, the SOT-223 tab must be soldered to a PCB copper pad that acts as a heatsink. Power dissipation Pd=(Vin−3.3V)×Iload_Pd_​=(Vin_​−3.3_V)×_Iload_​. Example: 5V in, 500mA load = (5-3.3)*0.5 = 0.85W (requires good heatsinking).

⚠️ Critical Design Notes & Limitations:

• Capacitor ESR Requirement: For stability, the output capacitor must have an ESR between 0.3Ω and 22Ω. Most 22µF tantalum or low-ESR electrolytic capacitors meet this. Large ceramic capacitors (e.g., 10µF X7R) may cause instability unless a small 1Ω resistor is placed in series with them.

• Heat Dissipation is Key: This is a linear regulator – excess voltage is dissipated as heat. For high-current or high input voltage applications, thermal management is crucial.

• Input Voltage Limit: Do not exceed 15V for continuous operation. A reverse diode on the input is recommended if the input source can be disconnected before the output load.

• Not a Switching Regulator: Inefficient for large voltage differences (e.g., 12V to 3.3V at high current). For such cases, use a buck converter (e.g., MP2307).

• Pinout: The common SOT-223 pinout (front view, tab facing you) is: Pin 1: Ground (Adj) / Pin 2: Vout / Pin 3: Vin. The tab is connected to Vout.