ADS1115 16-Bit ADC I2C Analog-to-Digital Converter Module | ATMOSFÆR ENGINEERING

High-precision 16-bit analog-to-digital converter with programmable gain amplifier (PGA) and I2C interface. Provides four single-ended or two differential input channels with up to 860 samples per second. Ideal for reading analog sensors with high accuracy on microcontrollers with limited or no ADC capabilities (like Raspberry Pi) or when higher resolution than built-in ADCs is required.

Technical Specifications:

• IC: Texas Instruments ADS1115
• Resolution: 16-bit (65,536 levels)
• Interface: I2C (TWI)
• Input Channels: 4 single-ended or 2 differential inputs
• Sample Rate: 8 to 860 samples per second (SPS), programmable
• Operating Voltage: 2.0V - 5.5V
• I2C Address: 0x48 (default), configurable to 0x49, 0x4A, 0x4B via ADDR pin
• Programmable Gain Amplifier (PGA): ±6.144V, ±4.096V, ±2.048V, ±1.024V, ±0.512V, ±0.256V
• Input Voltage Range: VSS-0.3V to VDD+0.3V (within selected PGA range)
• Accuracy: ±3 LSB (typical)
• Operating Temperature: -40°C to +125°C
• Module Dimensions: ~22mm x 15mm (typical)

Pin Configuration:

• VDD: Power supply (2.0V - 5.5V)
• GND: Ground
• SDA: I2C data line
• SCL: I2C clock line
• ADDR: Address select pin (connect to GND/VDD/SDA/SCL for address selection)
• ALRT: Alert/ready output (programmable comparator/conversion ready)
• A0-A3: 4 analog input channels

Features:

• True 16-bit resolution (vs 10-12 bit on most microcontrollers)
• Programmable gain for measuring small signals accurately
• Single-ended or differential input modes
• Onboard voltage reference for accuracy
• Continuous or single-shot conversion modes
• Programmable comparator with alert function
• Low power consumption: 150μA continuous, 0.5μA power-down
• Internal oscillator
• I2C interface uses only 2 wires

Input Modes:

• Single-ended: A0, A1, A2, A3 (4 independent inputs vs GND)
• Differential: A0-A1, A2-A3 (2 differential pairs)

Gain Settings:

• ±6.144V: 0.1875mV per bit
• ±4.096V: 0.125mV per bit
• ±2.048V: 0.0625mV per bit (default)
• ±1.024V: 0.03125mV per bit
• ±0.512V: 0.015625mV per bit
• ±0.256V: 0.0078125mV per bit

Applications:

• High-precision sensor reading (temperature, pressure, strain gauges)
• Raspberry Pi analog input (Pi has no built-in ADC)
• Battery voltage monitoring
• Industrial measurement and data acquisition
• Load cell and weight measurement
• pH sensor and water quality monitoring
• Multi-channel voltage logging
• Audio signal measurement
• Bridge sensor interfacing (thermocouples, load cells)

Advantages over Built-in ADCs:

• 16-bit vs 10-12 bit (Arduino/ESP32)
• Programmable gain for small signal amplification
• Differential inputs reduce common-mode noise
• Works with Raspberry Pi (no built-in ADC)

Compatible with Arduino, ESP32, Raspberry Pi, STM32, and any microcontroller with I2C support. Libraries available for Arduino IDE and Python (Adafruit, etc.).