Overview

The HDC1080 is a low-power, high-accuracy digital relative humidity and temperature sensor manufactured by Texas Instruments. Housed in a ultra-compact 3.0×3.0 mm3.0 \times 3.0\text{ mm} 6-pin WSON package, it measures relative humidity from 0% to 100% RH0\%\text{ to }100\%\text{ RH} and ambient temperature from −40∘C to +125∘C-40^\circ\text{C}\text{ to }+125^\circ\text{C}.

Featuring typical accuracies of ±2% RH\pm 2\%\ \text{RH} and ±0.2∘C\pm 0.2^\circ\text{C}, 14-bit ADC resolution, an integrated heating element (for condensation removal), and an I2CI^2C interface (0x40), the HDC1080 draws an average of just 1.3 μA1.3\ \mu\text{A} at 1 Hz sampling (700 nA700\text{ nA} in sleep mode). It is ideal for battery-powered environmental monitoring, smart thermostats, and weather stations.

Quick reference

Operating voltage (VDD)2.7 V to 5.5 V DC (3.3 V or 5.0 V nominal)
InterfaceI2CI^2C (up to 400 kHz)
Fixed I2CI^2C address0x40
Humidity range & accuracy0% to 100% RH0\%\text{ to }100\%\text{ RH} (±2% RH\pm 2\%\ \text{RH} typical)
Temperature range & accuracy−40∘C to +125∘C-40^\circ\text{C}\text{ to }+125^\circ\text{C} (±0.2∘C\pm 0.2^\circ\text{C} typical)
ADC resolution14-bit (configurable to 11-bit or 8-bit in register 0x02)
Internal heaterSoftware-controlled integrated heating element for de-fogging
Average power draw1.3 μA1.3\ \mu\text{A} at 1 sample/sec / 700 nA700\text{ nA} sleep

Pinout

Breakout module 4-pin header:

PinNameTypeDescription
1VCCPowerSupply power input (+2.7 V to +5.5 V DC)
2GNDPowerGround reference (0 V)
3SCLDigital InputI2CI^2C Serial Clock
4SDADigital Input / OutputI2CI^2C Serial Data

Specifications

ParameterSymbolMinTypMaxUnitConditions
Supply VoltageVDDV_{DD}2.73.3 / 5.05.5VDC
Active Conversion CurrentIactiveI_{active}—210300µAActive sampling
Sleep CurrentIsleepI_{sleep}—0.71.1µASleep state
Temp Accuracy (20∘C…60∘C20^\circ\text{C}\dots 60^\circ\text{C})TaccT_{acc}-0.2±0.2\pm 0.2+0.2°CTypical accuracy
RH Accuracy (20%…80%20\%\dots 80\%)RHaccRH_{acc}-2.0±2.0\pm 2.0+2.0% RHTypical accuracy at 25∘C25^\circ\text{C}
Conversion Time (14-bit)tconvt_{conv}—6.5 (T) / 6.5 (RH)—msDual measurement

Data Calculations & Math

  • Temperature Register (0x00):

Temperature (∘C)=(Raw 16-bit Temp Register65536)×165.0−40.0\text{Temperature } (^\circ\text{C}) = \left( \frac{\text{Raw 16-bit Temp Register}}{65536} \right) \times 165.0 - 40.0

  • Humidity Register (0x01):

Relative Humidity (% RH)=(Raw 16-bit RH Register65536)×100.0%\text{Relative Humidity } (\%\text{ RH}) = \left( \frac{\text{Raw 16-bit RH Register}}{65536} \right) \times 100.0\%

Wiring

HDC1080 Pin→Arduino / MCUESP32Notes
VCC5V / 3.3V3.3VPower rail
GNDGNDGNDSystem ground
SCLA5GPIO 22I2CI^2C Clock
SDAA4GPIO 21I2CI^2C Data

Example (ClosedCube_HDC1080 Library)

cpp
#include <Wire.h>
#include "ClosedCube_HDC1080.h"

ClosedCube_HDC1080 hdc1080;

void setup() {
  Serial.begin(115200);
  Wire.begin();

  Serial.println("TI HDC1080 Temp & Humidity Sensor Test");
  
  // Default I2C Address 0x40
  hdc1080.begin(0x40);

  Serial.print("Device Manufacturer ID: 0x");
  Serial.println(hdc1080.readManufacturerId(), HEX);
}

void loop() {
  float temp = hdc1080.readTemperature();
  float humidity = hdc1080.readHumidity();

  Serial.print("Temperature: "); Serial.print(temp); Serial.print(" °C | ");
  Serial.print("Humidity: "); Serial.print(humidity); Serial.println(" % RH");

  delay(2000);
}

Common mistakes

  • Forgetting I2C bus address: HDC1080 has a fixed hardcoded I2CI^2C address (0x40). Sharing the bus with other fixed 0x40 devices (such as the HTU21D or INA219) causes I2CI^2C bus conflicts.
  • Self-heating from onboard heater: The HDC1080 includes an internal heating element (bit 13 in Configuration register 0x02). Keep the heater OFF during normal environmental sensing to avoid +5∘C⋯+10∘C+5^\circ\text{C}\dots +10^\circ\text{C} temperature measurement errors. Enable the heater only briefly to evaporate water condensation.

Notes

  • HDC1080 vs HDC2080 vs HTU21D: HDC1080 is ±2% RH\pm 2\%\ \text{RH} accurate over I2CI^2C; HDC2080 is the updated ultra-low-power version (50 nA50\text{ nA} sleep); HTU21D is TE Connectivity's equivalent sensor.

Assets & downloads