AMS1117 3.3V 1A Low Dropout Linear Voltage Regulator IC SOT-223

Specifications

• Operating Voltage (Input): Up to 15V DC (Maximum)
• Operating Voltage (Output): 3.3V DC (Fixed)
• Output Current: 1A (Maximum)
• Dropout Voltage: 1.3V (Maximum at 0.8A/1A load)
• Line Regulation: 0.2% (Max)
• Load Regulation: 0.4% (Max)
• Quiescent Current: 5mA (Typical), 11mA (Max)
• Package Type: SOT-223 (Surface Mount)
• Pin Configuration: Pin 1 (Ground), Pin 2 (VOUT), Pin 3 (VIN), Tab (VOUT)
• Operating Junction Temperature: -40°C to +125°C
• Built-in Protection: Current limiting and thermal overload shutdown at 165°C

Applications

• High Efficiency Linear Regulators
• Post Regulators for Switching Supplies
• 5V to 3.3V Linear Regulator
• Battery Chargers
• Active SCSI Terminators
• Power Management for Notebook
• Battery Powered Instrumentation

Package Includes:

• 1 x AMS1117 3.3V 1A Low Dropout Linear Voltage Regulator IC SOT-223

Frequently Asked Questions

• What is the AMS1117-3.3?
  The AMS1117-3.3 is a fixed surface-mount low-dropout (LDO) linear voltage regulator that steps down a higher DC input voltage to a steady, regulated 3.3V DC output at up to 1A.
• How does the fixed AMS1117-3.3 differ from the adjustable version?
  The fixed version has internal precision trimming resistors that lock the output to exactly 3.3V, mapping Pin 1 directly to Ground. The adjustable version requires external resistor dividers connected to Pin 1 (ADJ) to set the output voltage manually.
• What does "LDO" mean for the AMS1117?
  LDO stands for Low Dropout. Unlike older linear regulators (like the LM78xx series) which require an input voltage at least 2V–3V higher than the output, the AMS1117 operates down to a 1.1V–1.3V differential, saving power and minimizing heat.
• What is the absolute maximum input voltage for the AMS1117-3.3?
  The absolute maximum rating for the input voltage is 15V DC. Exceeding this limit will cause electrical breakdown of the silicon substrate and permanently destroy the IC.
• Can I use a 12V DC input to drop down to a 3.3V output?
  Yes, but you must strictly limit the output current. Dropping from 12V to 3.3V creates an 8.7V differential (V_IN - V_OUT). At a moderate current draw of 100mA, the IC must dissipate 0.87\text(Watts) of raw heat, causing it to run extremely hot on a small PCB space.
• What is the minimum input voltage required for a stable 3.3V output?
  The minimum input voltage is the output voltage plus the dropout voltage threshold (V_OUT + V_DROPOUT). Since the worst-case dropout is 1.3V, you need a minimum input voltage of 4.6V to guarantee stable regulation under load.