Analog signals from sensors and electronic devices must be converted into digital data before microcontrollers can process them. Analog-to-digital converters (ADCs) play an important role here. Among many available ADC solutions, the ADS1115 from Texas Instruments is widely used. This article will discuss the ADS1115 ADC, pinout details, hardware configuration, specifications, features, Arduino interfacing, etc.

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ADS1115 IC ADC Basic

The ADS1115 is a high-precision 16-bit analog-to-digital converter (ADC) designed to convert analog voltage signals into digital data that microcontrollers can process. It operates from a single power supply of 2.0V to 5.5V and communicates through an I²C-compatible serial interface, allowing easy integration with embedded systems such as Arduino, Raspberry Pi, and other microcontroller platforms. The device includes an internal reference and oscillator, simplifying circuit design and reducing the number of external components required.

The ADS1115 also features an integrated programmable gain amplifier (PGA) that allows measurement of very small signals, with input ranges down to ±256 mV. It can perform conversions at speeds of up to 860 samples per second (SPS) and includes an internal multiplexer (MUX) supporting four single-ended inputs or two differential inputs, making it suitable for multi-sensor data acquisition and precision measurement systems.

If you are interested in purchasing the ADS1115, feel free to contact us for pricing and availability.

ADS1115 ADC CAD Models

ADS1115 ADC Pinout Details

Alternatives & Equivalent Model

• ADS1015

• ADS1114

• ADS1113

• MCP3008

• MCP3424

• PCF8591

• MAX11612

• ADS1118

ADS1115 Basic Hardware Configuration

The circuit diagram shows the basic hardware connection of the ADS1115 analog-to-digital converter with a microcontroller using the I²C communication interface. The ADS1115 operates from a 3.3 V power supply, where the VDD pin is connected to the supply voltage and the GND pin is connected to ground. A 100 nF bypass capacitor is placed between VDD and GND to stabilize the power supply and reduce electrical noise during operation.

The SDA (Serial Data) and SCL (Serial Clock) pins connect the ADS1115 to the microcontroller’s I²C bus. In this example, the microcontroller communicates with the ADC through pins P1.7 (SDA) and P1.6 (SCL). Two 10 kΩ pull-up resistors are connected from SDA and SCL to the 3.3 V supply. These resistors are required for proper I²C communication because the bus uses open-drain signaling.

The AIN0–AIN3 pins are the analog input channels used to measure external signals. These inputs allow the ADS1115 to read sensor outputs or other analog voltages. The ADDR pin selects the I²C address of the device so that multiple ADCs can share the same bus. The ALERT pin (available on ADS1114 and ADS1115) can act as a comparator output or a conversion-ready signal to notify the microcontroller when a measurement is complete.

ADS1115 ADC Functional Block Diagram

The ADS1115 receives analog signals through the AIN0–AIN3 input pins, which are connected to an internal multiplexer (MUX). The MUX selects one input channel or differential pair so the ADC can measure different signals using a single converter.

The selected signal then passes through the programmable gain amplifier (PGA), which adjusts the signal level for better measurement accuracy. After amplification, the signal is converted into digital data by the 16-bit delta-sigma (ΔΣ) ADC, using an internal voltage reference and oscillator to control the conversion process.

The converted data is sent to a microcontroller through the I²C interface using the SCL and SDA pins. The ADDR pin sets the device address, while the ALERT/RDY pin can act as a comparator output or indicate when a conversion is complete.

ADS1115 ADC Specifications

ADS1115 ADC Features

High-Resolution 16-Bit ADC

The ADS1115 provides 16-bit resolution, allowing it to measure analog signals with high precision. This makes it suitable for applications that require accurate data acquisition, such as sensor monitoring and measurement systems.

Wide Operating Voltage Range

The device operates with a power supply from 2.0 V to 5.5 V, allowing easy integration with both low-voltage and standard digital systems such as microcontrollers and embedded platforms.

Low Power Consumption

The ADS1115 is designed for low-power operation, consuming about 150 µA in continuous conversion mode. In single-shot mode, the device automatically powers down after each conversion to further reduce power usage.

Programmable Data Rate

The ADC supports programmable sampling rates from 8 SPS to 860 SPS, allowing designers to balance conversion speed and measurement accuracy depending on the application.

Integrated Programmable Gain Amplifier (PGA)

The built-in PGA allows adjustable gain settings, enabling the ADS1115 to accurately measure both small and large analog signals without external amplification.

Multiple Analog Input Channels

The ADS1115 supports four single-ended inputs or two differential inputs, allowing multiple sensors or signals to be monitored using a single ADC device.

I²C Communication Interface

The device uses a standard I²C interface with selectable addresses, making it easy to connect multiple ADS1115 converters to the same communication bus.

Built-In Voltage Reference and Oscillator

An internal low-drift voltage reference and oscillator provide stable operation and accurate conversions without requiring external reference components.

Programmable Comparator with ALERT/RDY Output

The ADS1115 includes a programmable comparator that can trigger the ALERT/RDY pin when input signals cross predefined thresholds or when a conversion is complete.