Datasheet

ADC

TEMPERATURE

Registers

Logic

HDC1080

SDA

SCL

OTP

Calibration Coefficients

VDD

GND

HDC1080

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SNAS672A –NOVEMBER 2015–REVISED JANUARY 2016

8 Detailed Description

8.1 Overview

The HDC1080 is a digital humidity sensor with integrated temperature sensor that provides excellent

measurement accuracy at very low power. The sensing element of the HDC1080 is placed on the top part of the

device. Measurement results can be read out through the I2C compatible interface. Resolution is based on the

measurement time and can be 8, 11, or 14 bits for humidity; 11 or 14 bits for temperature.

8.2 Functional Block Diagram

8.3 Feature Description

8.3.1 Power Consumption

One of the key features of the HDC1080 is its low power consumption, which makes the device suitable in

battery or power harvesting applications. In these applications the HDC1080 spends most of the time in sleep

mode: with a typical 100nA of current consumption in sleep mode, the averaged current consumption is minimal.

Its low consumption in measurement mode minimizes any self-heating.

8.3.2 Voltage Supply Monitoring

The HDC1080 monitors the supply voltage level and indicates when the voltage supply of the HDC1080 is less

than 2.8V. This information is useful in battery-powered systems in order to inform the user to replace the

battery. This is reported in the BTST field (register address 0x02:bit[11]) which is updated after POR and after

each measurement request.

8.3.3 Heater

The heater is an integrated resistive element that can be used to test the sensor or to drive condensation off the

sensor. The heater can be activated using HEAT, bit 13 in the Configuration Register. The heater helps in

reducing the accumulated offset after long exposure at high humidity conditions.

Once enabled the heater is turned on only in the measurement mode. To accelerate the temperature increase it

is suggested to increase the measurement data rate.

8.4 Device Functional Modes

The HDC1080 has two modes of operation: sleep mode and measurement mode. After power up, the HDC1080

is in sleep mode. In this mode, the HDC1080 waits for I2C input including commands to configure the conversion

times, read the status of the battery, trigger a measurement, and read measurements. Once it receives a

command to trigger a measurement, the HDC1080 moves from sleep mode to measurement mode. After

completing the measurement the HDC1080 returns to sleep mode.

Product Folder Links: HDC1080