BME280 Combined Humidity and Pressure Sensor

The BME280 is an integrated environmental sensor developed specifically for mobile applications where size and low power consumption are key design constraints. The unit combines individual high linearity, and high accuracy sensors for pressure, humidity, and temperature in an 8-pin metal-lid 2.5 x 2.5 x 0.93mm LGA package.

 

BME280 Pinout Configuration

Pin Number	Pin Name	Pin Description
1	GND	Ground
2	CSB	Chip Select
3	SDI	Serial Data Interface
4	SCK	Serial Clock Interface
5	SDO	Serial Data Output
6	VDDIO	Digital/Interface Supply
7	GND	Ground
8	VDD	Analog Supply

 

Features & Specifications

• Built for Mobile Application and Comes in a 2.6mm x 2.5mm x 0.93mm metal lid LGA
• Digital Interface I2C (up to 3.4 MHz) and SPI (3 and 4wire up to 10 MHz)
• Main Supply Voltage Range: 1.71V to 3.6V
• Interface Voltage Range: 1.2 V to 3.6 V
• Current Consumption: 1.8uA @ 1Hz Humidity and Temperature
• Operating Range: -40 to +85 C, Rel. Humidity: 0...100%, Pressure: 300...1100hPa
• Register and performance compatible to Bosch Sensor Tec BMP280 pressure sensor
• RoHS compliant, halogen-free, MSL1
• Humidity sensor and pressure sensor can be independently enabled /disabled

 

Note: Complete Technical Details can be found in the BME280 datasheet given at the end of this page.

 

BME280 Equivalent Sensors

BME180, BMP280, HTU21D

 

General Description of BME280 Sensor IC

The BME280 is a combined digital humidity, pressure, and temperature sensor. The sensor module is housed in an extremely compact metal-lid LGA package with a footprint of only 2.5 x 1.5 mrn2 with a height of 0.93 mm. Its small dimensions with low power consumption provide an edge for battery-driven devices such as handsets, GPS modules, or watches. The BME280 achieves high performance in all applications requiring humidity and pressure measurement. These emerging applications of home automation control, in-door navigation, fitness as well as GPS refinement require high accuracy and a low TCO at the same time.

The humidity sensor provides an extremely fast response time for fast context awareness applications, the pressure sensor is a barometric pressure sensor with high accuracy and resolution. The integrated temperature sensor has the lowest noise and highest resolution. Its output is used for temperature compensation of the pressure and humidity sensors and can also be used for the estimation of the ambient temperature.

The sensor provides both SPI and I2C interfaces and can be supplied using 1.71 to 3.6 V for the sensor supply V_CC and 1.2 to 3.6 V for the interface supply. Measurements can be triggered by the host or performed in regular intervals. When the sensor is disabled, current consumption drops to 0.1 pA.

 

How to use the BME280 Sensor IC

The BME280 sensor operates from 1.7-3.3V so it can be driven with 3.3V logic levels. If there is a need for 5V operations, it can be done using a voltage regulator and level shifters as it doesn’t contain one. It is typically recommended to operate it on 3.3V and maximum at 3.6VDC.

The BME280 module simply supports both I2C and SPI interfaces and comes with a default I2C address of 0x76. The Chip Select (CSB) and Serial Data Output (SDO) pins of the BMP 280 are necessary only when SPI-based (four-wire) communication is applied. I2C is a two-wire interface SDA SCK. Leave pin 6 of the module (SDO) unconnected to set the I2C address to 0x76 – the onboard resistor pulls the SDO pin low, setting the address to 0x76. To change the I2C address to 0x77, connect pin 6 of the module (SDO) to V_cc which would typically be the 3.3V supply. Pin 5 of the module (CSB) must be connected to V_cc to select the I2C interface. This is already done by an onboard pull-up resistor, so pin 5 can be left disconnected when using the I2C interface. The connection diagram for I2C and SPI configuration is shown below.

Applications

• Context awareness, e.g. skin detection, room change detection
• Fitness monitoring/well-being
• Measurement of volume and air flow
• Home automation control
• control heating, venting, air conditioning (HVAC)
• Internet of things
• GPS enhancement (time-to-first-fix improvement, dead reckoning, slope detection)
• Indoor navigation (change of floor detection, elevator detection)
• Outdoor navigation, leisure, and sports applications
• Weather forecast
• Vertical velocity indicator (rise/sink speed)

 

Target Devices

• Handsets such as mobile phones, tablet PCs, GPS devices
• Navigation systems
• Gaming, e.g. flying toys
• Camera (DSC, video)
• Home weather stations
• Flying toys
• Watches

 

2D Model and Dimensions

If you are designing a PCB or Perf board with this component then the following picture from the BME280 Datasheet will be useful to know its package type and dimensions.