# ADS1115 ADC: 16-bit, 4 inputs over I2C

> A 16-bit I2C converter with a gain amplifier and comparator: ranges, data rates, supply and when it beats a board's built-in ADC.

Canonical: https://roboticsengineering.in/components/ads1115-adc/ | Published: 2026-11-03 | Updated: 2026-11-03

**The ADS1115 is a 16-bit I2C analog-to-digital converter with four single-ended inputs (or two differential), a programmable gain amplifier, and a supply range of 2.0 to 5.5 V at 150 µA in continuous mode.** It adds clean, accurate analog inputs to a board whose own ADC is noisy or short of pins, which is common on the ESP32. Figures are from the Texas Instruments ADS111x datasheet.

## Key specifications

| Resolution | 16 bit |
| --- | --- |
| Inputs | 4 single-ended or 2 differential |
| Supply | 2.0–5.5 V, 150 µA |
| Data rate | 8–860 SPS |
| Input range | ±256 mV to ±6.144 V |
| Interface | I2C, 4 addresses |

## What the datasheet promises

| Item | Datasheet value |
| --- | --- |
| Resolution | 16 bit |
| Inputs (ADS1115) | 4 single-ended or 2 differential, through an input multiplexer |
| Supply voltage | 2.0 to 5.5 V |
| Current | 150 µA in continuous-conversion mode |
| Data rate | 8, 16, 32, 64, 128, 250, 475 or 860 samples per second |
| Input ranges (PGA) | ±256 mV up to ±6.144 V |
| Reference and clock | Internal low-drift voltage reference and oscillator |
| Comparator | Programmable, with an ALERT/RDY output pin |
| Interface | I2C, four pin-selectable addresses |
| Temperature | −40 °C to +125 °C |
| Packages | X2QFN-10, SOT-10, VSSOP-10 |

The sibling parts differ only in features: the ADS1113 has one input and no gain amplifier or comparator, the ADS1114 has one input with both, and the ADS1115 has the full set. Breakout boards almost always carry the ADS1115.

## Using it on a robot

- Pick the gain so the signal fills the range. At the ±256 mV setting the converter reads small shunt or bridge signals; at ±6.144 V it covers a 5 V sensor.
- Never drive an input above the supply plus a small margin; the datasheet’s absolute maximum ratings apply, so divide a battery voltage down first.
- Choose the address with the ADDR pin if you use more than one on the same bus.
- Use single-shot mode when you read rarely: the chip powers down between conversions.
- The ALERT/RDY pin can raise an interrupt on a threshold, for example a low-battery warning, without polling.

For battery voltage with a divider, see [battery voltage monitor reads wrong](https://roboticsengineering.in/fix/battery-voltage-monitor-divider-adc-reads-wrong/). To measure current as well as voltage in one part, the [INA219](https://roboticsengineering.in/components/ina219-current-sensor/) is the better fit. Many ADS1115 boards share the I2C bus with the [MPU6050](https://roboticsengineering.in/components/mpu6050-imu/) and the [PCA9685](https://roboticsengineering.in/components/pca9685-servo-driver/), so check that the addresses do not clash.

## Sources and further reading

- [Texas Instruments ADS1113, ADS1114, ADS1115 datasheet](https://www.ti.com/lit/ds/symlink/ads1115.pdf) — every figure in the table above.

Last reviewed: November 2026. Limits are from the Texas Instruments datasheet; breakout boards vary. No price is quoted because it has not been checked.