How to Use AMS1117 5.0 V: Examples, Pinouts, and Specs

The AMS1117 5.0 V is a low dropout (LDO) voltage regulator designed to provide a stable 5.0 V output with a maximum output current of 1 A. It is widely used in power supply circuits to regulate voltage levels for microcontrollers, sensors, and other electronic devices. Its compact size and ease of use make it a popular choice for both hobbyists and professionals.

• Powering microcontrollers (e.g., Arduino, ESP8266, Raspberry Pi peripherals)
• Voltage regulation for sensors and modules
• Battery-powered devices
• General-purpose power supply circuits

The AMS1117 5.0 V typically comes in a 3-pin SOT-223 or TO-252 package. The pinout is as follows:

1. Input Voltage: Connect a DC voltage source (6.5 V to 15 V) to the VIN pin. Ensure the input voltage is at least 1.1 V higher than the desired 5.0 V output to maintain proper regulation.
2. Output Voltage: Connect the load to the VOUT pin. The output will be a stable 5.0 V.
3. Ground Connection: Connect the ADJ/GND pin to the ground of the circuit.
4. Capacitors:
   • Place a 10 µF capacitor (electrolytic or ceramic) between VIN and GND to stabilize the input voltage.
   • Place a 10 µF capacitor between VOUT and GND to ensure stable output voltage and reduce noise.

• Heat Dissipation: The AMS1117 can generate heat under high current loads. Use a heatsink or ensure proper ventilation if the current exceeds 500 mA.
• Input Voltage Range: Do not exceed the maximum input voltage of 15 V to avoid damaging the regulator.
• Load Current: Ensure the load does not draw more than 1 A, as this is the maximum output current rating.
• Bypass Capacitors: Always use the recommended capacitors to prevent oscillations and ensure stable operation.

The AMS1117 5.0 V can be used to power an Arduino UNO from a 9 V battery. Below is an example circuit and Arduino code:

• Connect the 9 V battery's positive terminal to the VIN pin of the AMS1117.
• Connect the battery's negative terminal to the GND pin of the AMS1117.
• Connect the VOUT pin of the AMS1117 to the 5 V pin of the Arduino UNO.
• Connect the GND pin of the AMS1117 to the GND pin of the Arduino UNO.

// Example code to blink an LED connected to pin 13 of Arduino UNO
// Ensure the AMS1117 is providing a stable 5.0 V to the Arduino

void setup() {
  pinMode(13, OUTPUT); // Set pin 13 as an output pin
}

void loop() {
  digitalWrite(13, HIGH); // Turn the LED on
  delay(1000);            // Wait for 1 second
  digitalWrite(13, LOW);  // Turn the LED off
  delay(1000);            // Wait for 1 second
}

1. Output Voltage is Not 5.0 V:

   • Check the input voltage. Ensure it is at least 6.5 V.
   • Verify the capacitors are correctly connected and have the recommended values.
   • Ensure the load does not exceed 1 A.

2. Regulator Overheats:

   • Reduce the load current if it exceeds 500 mA.
   • Use a heatsink or improve ventilation around the AMS1117.

3. Oscillations or Noise on Output:

   • Ensure the input and output capacitors are placed as close as possible to the AMS1117.
   • Use low-ESR capacitors for better performance.

4. No Output Voltage:

   • Verify all connections, especially the ground connection.
   • Check if the AMS1117 is damaged due to overvoltage or overcurrent.

Q: Can I use the AMS1117 5.0 V with a 5 V input?
A: No, the input voltage must be at least 6.5 V to maintain proper regulation. The dropout voltage is approximately 1.1 V.

Q: What type of capacitors should I use with the AMS1117?
A: Use 10 µF electrolytic or ceramic capacitors with low ESR for both input and output.

Q: Can the AMS1117 power a Raspberry Pi?
A: No, the AMS1117 is not suitable for powering a Raspberry Pi, as it requires more current than the AMS1117 can provide.

Q: Is the AMS1117 suitable for battery-powered applications?
A: Yes, but ensure the input voltage remains within the specified range and consider the quiescent current for battery life.