Final data sheet BME280 Combined humidity and pressure sensor Bosch Sensortec BME280: Final data sheet Document revision 1.1 Document release date May 07 , 2015 Document number BST-BME280-DS001-10 Technical reference code(s) 0 273 141 185 Notes th Data in this document are subject to change without notice. Product photos and pictures are for illustration purposes only and may differ from the real product’s appearance.
Final Datasheet BME280 Environmental sensor Page 2 BME280 DIGITAL HUMIDITY, PRESSURE AND TEMPERATURE SENSOR Key features Package Digital interface Supply voltage 2.5 mm x 2.5 mm x 0.93 mm metal lid LGA I²C (up to 3.4 MHz) and SPI (3 and 4 wire, up to 10 MHz) VDD main supply voltage range: 1.71 V to 3.6 V VDDIO interface voltage range: 1.2 V to 3.6 V Current consumption 1.8 µA @ 1 Hz humidity and temperature 2.8 µA @ 1 Hz pressure and temperature 3.
Final Datasheet BME280 Environmental sensor Page 3 Gaming, e.g flying toys Camera (DSC, video) Portable health care devices Home weather stations Flying toys Watches General Description The BME280 is as combined digital humidity, pressure and temperature sensor based on proven sensing principles. The sensor module is housed in an extremely compact metal-lid LGA package with a footprint of only 2.5 × 2.5 mm² with a height of 0.93 mm.
Final Datasheet BME280 Environmental sensor Page 4 Index of Contents 1. SPECIFICATION ........................................................................................................................ 7 1.1 GENERAL ELECTRICAL SPECIFICATION .................................................................................. 7 1.2 HUMIDITY PARAMETER SPECIFICATION ................................................................................. 8 1.3 PRESSURE SENSOR SPECIFICATION ........................
Final Datasheet BME280 Environmental sensor Page 5 5.4.1 REGISTER 0XD0 “ID” ..................................................................................................................... 25 5.4.2 REGISTER 0XE0 “RESET”............................................................................................................... 25 5.4.3 REGISTER 0XF2 “CTRL_HUM” ........................................................................................................ 25 5.4.4 REGISTER 0XF3 “STATUS” ...
Final Datasheet BME280 Environmental sensor Page 6 8. APPENDIX A: ALTERNATIVE COMPENSATION FORMULAS ............................................ 49 8.1 COMPENSATION FORMULAS IN DOUBLE PRECISION FLOATING POINT ..................................... 49 8.2 PRESSURE COMPENSATION IN 32 BIT FIXED POINT .............................................................. 50 9. APPENDIX B: MEASUREMENT TIME AND CURRENT CALCULATION ............................ 51 9.1 MEASUREMENT TIME .....................................
Final Datasheet BME280 Environmental sensor Page 7 1.
Final Datasheet BME280 Environmental sensor Page 8 1.2 Humidity parameter specification2 Table 2: Humidity parameter specification Parameter Operating range 3 Supply current Absolute accuracy tolerance 4 Hysteresis Nonlinearity 5 Symbol Condition Min Typ Max Unit For temperatures < 0 °C and > 60 °C see Figure 1 -40 25 85 °C RH 100 %RH IDD,H 1 Hz forced mode, humidity and temperature 1.8 2.
Final Datasheet BME280 Environmental sensor Page 9 100 Relative humidity [%] 80 60 40 20 0 -40 -20 0 20 40 Temperature [°C] 60 80 Figure 1: humidity sensor operating range 1.6 Pressure sensor specification Table 3: Pressure parameter specification Parameter Symbol Condition Min Typ Max operational -40 25 +85 full accuracy 0 +65 300 1100 hPa 4.
Final Datasheet BME280 Environmental sensor Resolution of pressure output data RP Highest oversampling 0.18 Pa Full bandwidth, highest oversampling See chapter 3.6 1.3 Pa NP,fullBW 11 cm Reduced bandwidth, highest oversampling See chapter 3.6 0.2 Pa NP,filtered 1.7 cm Noise in pressure Minimum solder height 50µm Solder drift Long term stability 8 Possible sampling rate Page 10 Pstab per year fsample_P Lowest oversampling, see chapter 9.2 -0.5 157 +2.0 hPa ±1.
Final Datasheet BME280 Environmental sensor Page 11 Table 5: Absolute maximum ratings Parameter Voltage at any supply pin Condition Min Max Unit VDD and VDDIO pin -0.3 4.25 V -0.3 VDDIO + 0.3 V -45 +85 °C 0 20 000 hPa HBM, at any pin ±2 kV CDM ±500 V Machine model ±200 V Voltage at any interface pin Storage temperature ≤ 65% RH Pressure ESD Condensation No power supplied Allowed 3. Functional description 3.
Final Datasheet BME280 Environmental sensor Page 12 of raising the VDD and VDDIO levels. After powering up, the sensor settles in sleep mode (described in chapter 3.3.2). It is prohibited to keep any interface pin (SDI, SDO, SCK or CSB) at a logical high level when VDDIO is switched off. Such a configuration can permanently damage the device due an excessive current flow through the ESD protection diodes. If VDDIO is supplied, but VDD is not, the interface pins are kept at a high-Z level.
Final Datasheet BME280 Environmental sensor Page 13 3.3.2 Sleep mode Sleep mode is entered by default after power on reset. In sleep mode, no measurements are performed and power consumption (IDDSM) is at a minimum. All registers are accessible; Chip-ID and compensation coefficients can be read. There are no special restrictions on interface timings. current 3.3.3 Forced mode In forced mode, a single measurement is performed in accordance to the selected measurement and filter options.
current Final Datasheet BME280 Environmental sensor Page 14 Write POR settings Data readout when needed Mode[1:0] = 11 Measurement H Measurement P Measurement T IDDSB IDDSL Measurement H Measurement T IDDP IDDT IDDH Measurement P cycle time = tmeasure + tstandby tmeasure tstandby time Figure 5: Normal mode timing diagram 3.4 Measurement flow The BME280 measurement period consists of a temperature, pressure and humidity measurement with selectable oversampling.
Final Datasheet BME280 Environmental sensor Page 15 3.4.1 Humidity measurement The humidity measurement can be enabled or skipped. When enabled, several oversampling options exist. The humidity measurement is controlled by the osrs_h[2:0] setting, which is detailed in chapter 5.4.3. For the humidity measurement, oversampling is possible to reduce the noise. The resolution of the humidity measurement is fixed at 16 bit ADC output. 3.4.2 Pressure measurement Pressure measurement can be enabled or skipped.
Final Datasheet BME280 Environmental sensor Page 16 samples generated, which means that the data output rate must be known to calculate the actual response time. For register configuration, please refer to Table 28. A sample response time calculation is shown in chapter 9.4. Table 6: filter settings Filter coefficient Samples to reach ≥75 % of step response Filter off 1 2 2 4 5 8 11 16 22 In order to find a suitable setting for filter, please consult chapter 3.5.
Final Datasheet BME280 Environmental sensor Page 17 3.5 Recommended modes of operation The different oversampling options, filter settings and sensor modes result in a large number of possible settings. In this chapter, a number of settings recommended for various scenarios are presented. 3.5.1 Weather monitoring Description: Only a very low data rate is needed. Power consumption is minimal. Noise of pressure values is of no concern. Humidity, pressure and temperature are monitored.
Final Datasheet BME280 Environmental sensor Page 18 Table 9: Settings and performance for indoor navigation Suggested settings for indoor navigation Sensor mode normal mode, tstandby = 0.5 ms Oversampling settings pressure ×16, temperature ×2, humidity ×1 IIR filter settings filter coefficient 16 Performance for suggested settings Current consumption 633 µA RMS Noise 0.2 Pa / 1.7 cm Data output rate 25Hz Filter bandwidth 0.53 Hz Response time (75%) 0.9 s 3.5.4 Gaming Low altitude noise is needed.
Final Datasheet BME280 Environmental sensor Page 19 Table 11: Noise and current for humidity Humidity / temperature oversampling setting Typical RMS noise in humidity [%RH] at 25 °C Typ. current [µA] at 1 Hz forced mode, 25 °C, humidity and temperature measurement, incl. IDDSM ×1 / ×1 0.07 1.8 ×2 / ×1 0.05 2.5 ×4 / ×1 0.04 3.8 ×8 / ×1 0.03 6.5 ×16 / ×1 0.02 11.
Final Datasheet BME280 Environmental sensor Page 20 Table 14: Noise in temperature Temperature oversampling setting Typical RMS noise in temperature [°C] at 25 °C ×1 0.005 ×2 0.004 ×4 0.003 ×8 0.003 ×16 0.002 BST-BME280-DS001-10 | Revision 1.1 | May 2015 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties.
Final Datasheet BME280 Environmental sensor Page 21 4. Data readout To read out data after a conversion, it is strongly recommended to use a burst read and not address every register individually. This will prevent a possible mix-up of bytes belonging to different measurements and reduce interface traffic. Note that in I²C mode, even when pressure was not measured, reading the unused registers is faster than reading temperature and humidity data separately.
Final Datasheet BME280 Environmental sensor Page 22 Table 15: Computational requirements for compensation formulas Number of clocks (ARM Cortex-M3) Compensation of 32 bit integer 64 bit integer Humidity ~83 – ~2900 11 Temperature ~46 – ~2400 11 ~1400 ~5400 11 Pressure ~112 12 Double precision 4.2.2 Trimming parameter readout The trimming parameters are programmed into the devices’ non-volatile memory (NVM) during production and cannot be altered by the customer.
Final Datasheet BME280 Environmental sensor Page 23 0xE4 / 0xE5[3:0] dig_H4 [11:4] / [3:0] signed short 0xE5[7:4] / 0xE6 dig_H5 [3:0] / [11:4] signed short 0xE7 dig_H6 signed char 4.2.3 Compensation formulas Please note that it is strongly advised to use the API available from Bosch Sensortec to perform readout and compensation. If this is not wanted, the code below can be applied at the user’s risk.
Final Datasheet BME280 Environmental sensor Page 24 ((BME280_S32_t)dig_H3)) >> 11) + ((BME280_S32_t)32768))) >> 10) + ((BME280_S32_t)2097152)) * ((BME280_S32_t)dig_H2) + 8192) >> 14)); v_x1_u32r = (v_x1_u32r – (((((v_x1_u32r >> 15) * (v_x1_u32r >> 15)) >> 7) * ((BME280_S32_t)dig_H1)) >> 4)); v_x1_u32r = (v_x1_u32r < 0 ? 0 : v_x1_u32r); v_x1_u32r = (v_x1_u32r > 419430400 ? 419430400 : v_x1_u32r); return (BME280_U32_t)(v_x1_u32r>>12); } 5. Global memory map and register description 5.
Final Datasheet BME280 Environmental sensor Page 25 Table 18: Memory map Register Name Address hum_lsb hum_msb temp_xlsb temp_lsb temp_msb press_xlsb press_lsb press_msb config ctrl_meas status ctrl_hum calib26..calib41 reset id calib00..
Final Datasheet BME280 Environmental sensor Page 26 Table 19: Register 0xF2 “ctrl_hum” Register 0xF2 “ctrl_hum” Name Description Bit 2, 1, 0 osrs_h[2:0] Controls oversampling of humidity data. See Table 20 for settings and chapter 3.4.1 for details. Table 20: register settings osrs_h osrs_h[2:0] Humidity oversampling 000 Skipped (output set to 0x8000) 001 oversampling ×1 010 oversampling ×2 011 oversampling ×4 100 oversampling ×8 101, others oversampling ×16 5.4.
Final Datasheet BME280 Environmental sensor Page 27 Table 22: Register 0xF4 “ctrl_meas” Register 0xF4 “ctrl_meas” Name Bit 7, 6, 5 osrs_t[2:0] Bit 4, 3, 2 osrs_p[2:0] Bit 1, 0 mode[1:0] Description Controls oversampling of temperature data. See Table 24 for settings and chapter 3.4.3 for details. Controls oversampling of pressure data. See Table 23 for settings and chapter 3.4.2 for details. Controls the sensor mode of the device. See Table 25 for settings and chapter 3.3 for details.
Final Datasheet BME280 Environmental sensor Page 28 Table 26: Register 0xF5 “config” Register 0xF5 “config” Name Bit 7, 6, 5 t_sb[2:0] Bit 4, 3, 2 filter[2:0] Bit 0 spi3w_en[0] Description Controls inactive duration tstandby in normal mode. See Table 27 for settings and chapter 3.3.4 for details. Controls the time constant of the IIR filter. See Table 27 for settings and chapter 3.4.4 for details. Enables 3-wire SPI interface when set to ‘1’. See chapter 6.3 for details.
Final Datasheet BME280 Environmental sensor Page 29 Table 29: Register 0xF7 … 0xF9 “press” Register 0xF7…0xF9 “press” Name 0xF7 press_msb[7:0] 0xF8 press_lsb[7:0] 0xF9 (bit 7, 6, 5, 4) press_xlsb[3:0] Description Contains the MSB part up[19:12] of the raw pressure measurement output data. Contains the LSB part up[11:4] of the raw pressure measurement output data. Contains the XLSB part up[3:0] of the raw pressure measurement output data. Contents depend on temperature resolution. 5.4.
Final Datasheet BME280 Environmental sensor Page 30 6. Digital interfaces The BME280 supports the I²C and SPI digital interfaces; it acts as a slave for both protocols. The I²C interface supports the Standard, Fast and High Speed modes. The SPI interface supports both SPI mode ‘00’ (CPOL = CPHA = ‘0’) and mode ‘11’ (CPOL = CPHA = ‘1’) in 4wire and 3-wire configuration.
Final Datasheet BME280 Environmental sensor Page 31 The 7-bit device address is 111011x. The 6 MSB bits are fixed. The last bit is changeable by SDO value and can be changed during operation. Connecting SDO to GND results in slave address 1110110 (0x76); connection it to VDDIO results in slave address 1110111 (0x77), which is the same as BMP280’s I²C address. The SDO pin cannot be left floating; if left floating, the I²C address will be undefined.
Final Datasheet BME280 Environmental sensor Page 32 Control byte Slave Address Start S 1 1 1 0 1 Register address (F6h) RW ACKS 1 X 0 1 1 1 1 0 1 ACKS 1 0 Data byte Slave Address Start S 1 1 1 0 1 Register data - address F6h RW ACKS 1 X 1 Data byte bit7 bit6 bit5 bit4 bit3 bit2 Register data - address F7h ACKM bit1 bit0 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 NOACKM Stop P Figure 10: I²C multiple byte read 6.
Final Datasheet BME280 Environmental sensor Page 33 The SPI interface uses the following pins: CSB: chip select, active low SCK: serial clock SDI: serial data input; data input/output in 3-wire mode SDO: serial data output; hi-Z in 3-wire mode Refer to chapter 7 for connection instructions. CSB is active low and has an integrated pull-up resistor. Data on SDI is latched by the device at SCK rising edge and SDO is changed at SCK falling edge.
Final Datasheet BME280 Environmental sensor Control byte Register address (F6h) Start RW CSB = 0 1 1 1 1 0 1 1 0 Page 34 Data byte Data byte Data register - address F6h Data register - address F7h bit15 bit14 bit13 bit12 bit11 bit10 bit9 bit8 bit7 bit6 bit5 bit4 bit3 bit2 Stop bit1 bit0 CSB = 1 Figure 13: SPI multiple byte read 6.4 Interface parameter specification 6.4.1 General interface parameters The general interface parameters are given in Table 32 below.
Final Datasheet BME280 Environmental sensor Page 35 SDI tBUF tf tLOW SCK tHIGH tHDSTA tr tHDDAT tSUDAT SDI tSUSTA tSUSTO Figure 14: I²C timing diagram Table 33: I²C timings Parameter Symbol SDI setup time tSU;DAT SDI hold time tHD;DAT SCK low pulse tLOW SCK low pulse tLOW Condition Min S&F Mode HS mode S&F Mode, Cb≤100 pF S&F Mode, Cb≤400 pF HS mode, Cb≤100 pF HS mode, Cb≤400 pF HS mode, Cb≤100 pF VDDIO = 1.62 V HS mode, Cb≤100 pF VDDIO = 1.
Final Datasheet BME280 Environmental sensor Page 36 T_hold_csb T_setup_csb CSB T_low_sck T_high_sck SCK SDI T_setup_sdi T_hold_sdi SDO T_delay_sdo Figure 15: SPI timing diagram Table 34: SPI timings Parameter SPI clock input frequency SCK low pulse SCK high pulse SDI setup time SDI hold time SDO output delay SDO output delay CSB setup time CSB hold time Symbol F_spi T_low_sck T_high_sck T_setup_sdi T_hold_sdi T_delay_sdo T_delay_sdo T_setup_csb T_hold_csb BST-BME280-DS001-10 | Revision 1.
Final Datasheet BME280 Environmental sensor Page 37 7. Pin-out and connection diagram 7.1 Pin-out 8 VDD 1 GND 1 GND 8 VDD Pin 1 marker 7 GND 2 CSB 2 CSB 7 GND TOP VIEW (pads not visible) 6 VDDIO BOTTOM VIEW (pads visible) 3 SDI 3 SDI 6 VDDIO 4 SCK 4 SCK 5 SDO Vent hole 5 SDO Figure 16: Pin-out top and bottom view Note: The pin numbering of BME280 is performed in the untypical clockwise direction when seen in top view and counter-clockwise when seen in bottom view.
Final Datasheet BME280 Environmental sensor Page 38 7.2 Connection diagram I2C VDD VDDIO 8 VDD 1 GND 7 GND 2 CSB TOP VIEW (pads not visible) 6 VDDIO R1 R2 3 SDI SDA 4 SCK SCL Vent hole 5 SDO I2C address bit 0 GND: '0'; VDDIO: '1' C1 C2 Figure 17: I²C connection diagram Notes: The recommended value for C1, C2 is 100 nF The value for the pull-up resistors R1, R2 should be based on the interface timing and the bus load; a normal value is 4.
Final Datasheet BME280 Environmental sensor Page 39 7.3 Connection diagram 4-wire SPI VDD VDDIO 8 VDD 1 GND 7 GND 2 CSB CSB 3 SDI SDI 4 SCK SCK TOP VIEW (pads not visible) 6 VDDIO Vent hole 5 SDO SDO C1 C2 Figure 18: 4-wire SPI connection diagram Note: The recommended value for C1, C2 is 100 nF BST-BME280-DS001-10 | Revision 1.1 | May 2015 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights.
Final Datasheet BME280 Environmental sensor Page 40 7.4 Connection diagram 3-wire SPI VDD VDDIO 8 VDD 1 GND 7 GND 2 CSB CSB 3 SDI SDI/SDO 4 SCK SCK TOP VIEW (pads not visible) 6 VDDIO Vent hole 5 SDO C1 C2 Figure 19: 3-wire SPI connection diagram Note: The recommended value for C1, C2 is 100 nF BST-BME280-DS001-10 | Revision 1.1 | May 2015 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights.
Final Datasheet BME280 Environmental sensor Page 41 7.5 Package dimensions Figure 20: Package dimensions for top, bottom and side view BST-BME280-DS001-10 | Revision 1.1 | May 2015 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Final Datasheet BME280 Environmental sensor Page 42 7.6 Landing pattern recommendation For the design of the landing pattern, the following dimensioning is recommended: Figure 21: Recommended landing pattern (top view) Note: red areas demark exposed PCB metal pads. In case of a solder mask defined (SMD) PCB process, the land dimensions should be defined by solder mask openings. The underlying metal pads are larger than these openings.
Final Datasheet BME280 Environmental sensor Page 43 7.7 Marking 7.7.
Final Datasheet BME280 Environmental sensor Page 44 7.7.2 Engineering samples Table 37: Marking of engineering samples Marking Symbol XX 5 6 7 Sample ID: 2 alphanumeric digits, variable to generate trace-code 8 XXN CC Vent hole Description N Eng. Sample ID: 1 alphanumeric digit, fixed to identify engineering sample, N = “ * ” or “e” or “E” Pin 1 marker 4 3 2 1 CC BST-BME280-DS001-10 | Revision 1.
Final Datasheet BME280 Environmental sensor Page 45 7.8 Soldering guidelines and reconditioning recommendations The moisture sensitivity level of the BME280 sensors corresponds to JEDEC Level 1, see also: IPC/JEDEC J-STD-020C “Joint Industry Standard: Moisture/Reflow Sensitivity Classification for non-hermetic Solid State Surface Mount Devices” IPC/JEDEC J-STD-033A “Joint Industry Standard: Handling, Packing, Shipping and Use of Moisture/Reflow Sensitive Surface Mount Devices”.
Final Datasheet BME280 Environmental sensor Page 46 7.9 Reconditioning Procedure After exposing the device to operating conditions, which exceed the limits specified in section 1.2, e.g. after reflow, the humidity sensor may possess an additional offset. Therefore the following reconditioning procedure is mandatory to restore the calibration state: 1. Dry-Baking: 2. Re-Hydration: 120 °C at <5% rH for 2 h 70 °C at 75% rH for 6 h or alternatively 1. Dry-Baking: 2.
Final Datasheet BME280 Environmental sensor Page 47 7.10.2 Orientation within the reel Figure 24: Orientation within tape BST-BME280-DS001-10 | Revision 1.1 | May 2015 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Final Datasheet BME280 Environmental sensor Page 48 7.11 Mounting and assembly recommendations In order to achieve the specified performance for you design, the following recommendations and the “Handling, soldering & mounting instructions BME280” should be taken into consideration when mounting a pressure sensor on a printed-circuit board (PCB): The clearance above the metal lid shall be 0.1mm at minimum.
Final Datasheet BME280 Environmental sensor Page 49 8. Appendix A: Alternative compensation formulas 8.1 Compensation formulas in double precision floating point Please note that it is strongly advised to use the API available from Bosch Sensortec to perform readout and compensation. If this is not wanted, the code below can be applied at the user’s risk. Both pressure and temperature values are expected to be received in 20 bit format, positive, stored in a 32 bit signed integer.
Final Datasheet BME280 Environmental sensor Page 50 8.2 Pressure compensation in 32 bit fixed point Please note that it is strongly advised to use the API available from Bosch Sensortec to perform readout and compensation. If this is not wanted, the code below can be applied at the user’s risk. Both pressure and temperature values are expected to be received in 20 bit format, positive, stored in a 32 bit signed integer.
Final Datasheet BME280 Environmental sensor Page 51 9. Appendix B: Measurement time and current calculation In this chapter, formulas are given to calculate measurement rate, filter bandwidth and current consumption in different settings. 9.1 Measurement time The active measurement time depends on the selected values for humidity, temperature and pressure oversampling and can be calculated in milliseconds using the formulas below.
Final Datasheet BME280 Environmental sensor Page 52 9.4 Response time using IIR filter When using the IIR filter, the response time of the sensor depends on the selected filter coefficient and the data rate used. It can be calculated using the following formula: For the example above with a data rate of 13.51 Hz, the user could select a filter coefficient of 8. According to Table 6, the number of samples needed to reach 75% of a step response using this filter setting is 11.
Final Datasheet BME280 Environmental sensor Page 53 10. Legal disclaimer 10.1 Engineering samples Engineering Samples are marked with an asterisk (*) or (e) or (E). Samples may vary from the valid technical specifications of the product series contained in this data sheet. They are therefore not intended or fit for resale to third parties or for use in end products. Their sole purpose is internal client testing. The testing of an engineering sample may in no way replace the testing of a product series.
Final Datasheet BME280 Environmental sensor Page 54 11. Document history and modification Rev. No 0.1 Chapter 1.0 1.1 8.12.1 Description of modification/changes Document creation Date 2012-11-06 Final datasheet 2014-11-12 Updated RoHS directive to 2011/65/EU effective 8 June 2015-05-07 2011 Bosch Sensortec GmbH Gerhard-Kindler-Strasse 8 72770 Reutlingen / Germany contact@bosch-sensortec.com www.bosch-sensortec.
