How to Use ams5935: Examples, Pinouts, and Specs

The AMS5935 is a precision voltage reference manufactured by Analog Microelectronics. It provides a stable output voltage with a low temperature coefficient and low noise, making it ideal for high-accuracy applications. This component is commonly used in data acquisition systems, instrumentation, and other circuits requiring precise voltage references.

• Data acquisition systems
• Instrumentation and measurement equipment
• Analog-to-digital converters (ADCs)
• Digital-to-analog converters (DACs)
• Precision power supplies

The AMS5935 is designed to deliver high performance in demanding applications. Below are its key technical specifications:

The AMS5935 is available in multiple package types. Below is the pin configuration for the SOT-23 package:

For the SOIC-8 package, refer to the manufacturer's datasheet for the full pinout.

1. Power Supply: Connect the VIN pin to a stable power supply within the specified range (4.5V to 12V). Ensure the supply voltage is clean to avoid introducing noise into the reference output.
2. Ground Connection: Connect the GND pin to the circuit ground.
3. Output Voltage: The VOUT pin provides the precision reference voltage. Connect this pin to the load or circuit requiring the reference voltage.

• Bypass Capacitor: Place a 0.1 µF ceramic capacitor close to the VIN pin to filter out high-frequency noise from the power supply.
• Load Capacitance: The AMS5935 is stable with capacitive loads up to 10 µF. Use a capacitor at the VOUT pin to improve stability and reduce noise.
• Thermal Management: Ensure adequate thermal dissipation, especially in high-temperature environments, to maintain accuracy.
• PCB Layout: Minimize trace lengths and avoid running high-current traces near the AMS5935 to reduce noise coupling.

The AMS5935 can be used as a reference voltage for ADCs in microcontrollers like the Arduino UNO. Below is an example of how to connect and use it:

• Connect the AMS5935's VIN pin to the Arduino's 5V pin.
• Connect the GND pin to the Arduino's GND.
• Connect the VOUT pin to the AREF pin of the Arduino.

// Example code to use AMS5935 as an external reference for Arduino ADC

void setup() {
  // Set the analog reference to EXTERNAL to use AMS5935
  analogReference(EXTERNAL);

  // Initialize serial communication for debugging
  Serial.begin(9600);
}

void loop() {
  // Read an analog value from pin A0
  int sensorValue = analogRead(A0);

  // Convert the ADC value to voltage (assuming AMS5935 outputs 2.5V)
  float voltage = (sensorValue / 1023.0) * 2.5;

  // Print the voltage to the Serial Monitor
  Serial.print("Voltage: ");
  Serial.print(voltage);
  Serial.println(" V");

  delay(1000); // Wait for 1 second before the next reading
}

• Ensure the AMS5935 output voltage matches the Arduino's AREF pin voltage setting.
• Use a stable power supply to avoid fluctuations in the reference voltage.

1. Output Voltage is Incorrect:

   • Verify the input voltage is within the specified range (4.5V to 12V).
   • Check for proper connections and ensure the GND pin is securely connected to the circuit ground.
   • Ensure the load connected to the VOUT pin does not exceed the maximum current rating.

2. High Noise on Output:

   • Add a bypass capacitor (0.1 µF) close to the VIN pin.
   • Use a low-ESR capacitor (e.g., 1 µF to 10 µF) at the VOUT pin to filter noise.

3. Device Overheating:

   • Check for excessive input voltage or high ambient temperature.
   • Ensure proper thermal dissipation by using a heat sink or improving airflow.

4. Arduino ADC Readings are Inaccurate:

   • Confirm the AMS5935 output voltage matches the AREF voltage setting in the Arduino code.
   • Use shielded cables for analog signal connections to reduce noise interference.

Q: Can the AMS5935 be used with a 3.3V system?
A: Yes, the AMS5935 is available in models with a 3.3V output. Ensure the input voltage is at least 4.5V.

Q: What is the maximum load current for the AMS5935?
A: The AMS5935 can typically source up to 10 mA. Exceeding this limit may cause voltage drops or instability.

Q: Is the AMS5935 suitable for battery-powered applications?
A: Yes, its low supply current (1.0 mA typical) makes it suitable for battery-powered systems, provided the input voltage is within range.

Q: Can I use the AMS5935 without a load capacitor?
A: While the AMS5935 is stable without a load capacitor, adding one (e.g., 1 µF) improves noise performance and stability.