Data sheet BMP085 Digital pressure sensor Bosch Sensortec BMP085: Data sheet Document revision 1.3 Document release date 22 August 2011 Document number BST-BMP085-DS000-06 Technical reference code(s) 0 273 300 144 Notes 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.
Data sheet BMP085 Page 2 BMP085 DIGITAL PRESSURE SENSOR Key features • Pressure range: • Supply voltage: 300 ... 1100hPa (+9000m ... -500m above sea level) 1.8 ... 3.6V (VDDA) 1.62V ... 3.6V (VDDD) • LCC8 package: Robust, ceramic lead-less chip carrier (LCC) package Small footprint: 5.0mm x 5.0mm Super-flat: 1.2mm height • Low power: 5μA at 1 sample / sec. in standard mode • Low noise: 0.06hPa (0.5m) in ultra low power mode 0.03hPa (0.25m) ultra high resolution mode down to 0.
Data sheet BMP085 Page 3 Typical applications • Enhancement of GPS navigation (dead-reckoning, slope detection, etc.) • In- and out-door navigation • Leisure and sports • Weather forecast • Vertical velocity indication (rise/sink speed) New features comparison Smaller package height Faster conversion time (standard mode each) Faster I2C data transfer Extended min. supply voltage Lower stand-by current (typ.) External clock BST-BMP085-DS000-06 | Revision 1.3 | August 2011 BMP085 1.2mm 7.5ms (max.) max.
Data sheet BMP085 Page 4 Index of Contents 1. ELECTRICAL CHARACTERISTICS ....................................................................................... 6 2. ABSOLUTE MAXIMUM RATINGS .......................................................................................... 8 3. OPERATION ............................................................................................................................ 9 3.1 GENERAL DESCRIPTION...............................................................
Data sheet BMP085 Page 5 6. LEGAL DISCLAIMER ............................................................................................................ 26 6.1 ENGINEERING SAMPLES ...................................................................................................... 26 6.2 PRODUCT USE .................................................................................................................... 26 6.3 APPLICATION EXAMPLES AND HINTS ....................................................
Data sheet BMP085 Page 6 1. Electrical characteristics If not stated otherwise, the given values are maximum values over temperature/voltage range in the given operation mode. Table 1: Electrical characteristics Parameter Symbol Operating temperature TA Supply voltage VDD Condition Min operational -40 +85 full accuracy 0 +65 ripple max. 50mVpp 1.8 2.5 3.6 V 1.62 2.5 3.
Data sheet BMP085 Noise in pressure Absolute accuracy temperature VDD = 3.3V Page 7 see table on page 12 @ 25 °C -1.5 ±0.5 +1.5 °C 0 . . . +65 °C -2.0 ±1.0 +2.0 °C Solder drifts Minimum solder height 50μm ±1.0 hPa Long term stability 12 months ±1.0 hPa BST-BMP085-DS000-06 | Revision 1.3 | August 2011 Bosch Sensortec © Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights.
Data sheet BMP085 Page 8 2. Absolute maximum ratings Table 2: Absolute maximum ratings Parameter Condition Storage temperature Supply voltage all pins ESD rating HBM, R = 1.5kΩ, C = 100pF Overpressure Min Max Units -40 +85 °C -0.3 +4.25 V ±2 kV 10,000 hPa The BMP085 has to be handled as Electrostatic Sensitive Device (ESD). Figure 1: ESD BST-BMP085-DS000-06 | Revision 1.
Data sheet BMP085 Page 9 3. Operation 3.1 General description The BMP085 is designed to be connected directly to a microcontroller of a mobile device via the I2C bus. The pressure and temperature data has to be compensated by the calibration data of the E2PROM of the BMP085. 3.2 General function and application schematics The BMP085 consists of a piezo-resistive sensor, an analog to digital converter and a control unit with E2PROM and a serial I2C interface.
Data sheet BMP085 Page 10 Typical application circuit: 1.8 ... 3.6V 100nF Rp(1) VDDA Rp(1) VDDD 2 E PROM μController e. g. 8 bit BMP085 EOC Control Unit SDA SCL I2C interface XCLR Sensor element ADC GND Note: (1) Pull-up resistors for I2C bus, Rp = 2.2kΩ ... 10kΩ, typ. 4.7kΩ Display Note: The BMP085 can be supplied independently with different levels of VDDA and VDDD, which is not possible with the SMD500.
Data sheet BMP085 Page 11 3.3 Measurement of pressure and temperature For all calculations presented here an ANSI C code is available from Bosch Sensortec (“BMP085_SMD500_API”). The microcontroller sends a start sequence to start a pressure or temperature measurement. After converting time, the result value (UP or UT, respectively) can be read via the I2C interface. For calculating temperature in °C and pressure in hPa, the calibration data has to be used.
Data sheet BMP085 Page 12 Table 3: Overview of BMP085 modes, selected by driver software via the variable oversampling_setting Mode Parameter oversampling_ setting Internal number of samples Conversion time pressure max. [ms] Avg. current @ 1 sample/s typ. [μA] RMS noise typ. [hPa] RMS noise typ. [m] ultra low power 0 1 4.5 3 0.06 0.5 standard 1 2 7.5 5 0.05 0.4 high resolution 2 4 13.5 7 0.04 0.3 ultra high resolution 3 8 25.5 12 0.03 0.
Data sheet BMP085 Page 13 3.5 Calculation pressure and temperature The mode (ultra low power, standard, high, ultra high resolution) can be selected by the variable oversampling_setting (0, 1, 2, 3) in the C code. The universal code SMD500/BMP085 is fully upward compatible to SMD500 and recognizes automatically the device ID. Thus, the SMD500 can be replaced "on the fly" by the BMP085 without changing hardware or software. Calculation of true temperature and pressure in steps of 1Pa (= 0.01hPa = 0.
Data sheet BMP085 Page 14 Calculation of pressure and temperature for BMP085 Start C code function: example: Read calibration data 2 from the E PROM of the BMP085 2 read out E PROM registers, 16 bit, MSB first AC1 (0xAA, 0xAB) (16 bit) AC2 (0xAC, 0xAD) (16 bit) AC3 (0xAE, 0xAF) (16 bit) AC4 (0xB0, 0xB1) (16 bit) AC5 (0xB2, 0xB3) (16 bit) AC6 (0xB4, 0xB5) (16 bit) B1 (0xB6, 0xB7) (16 bit) B2 (0xB8, 0xB9) (16 bit) MB (0xBa, 0xBB) (16 bit) MC (0xBC, 0xBD) (16 bit) MD (0xBE , 0xBF) (16 bit) read uncompensa
Data sheet BMP085 Page 15 3.6 Calculation absolute altitude With the measured pressure p and the pressure at sea level p0 e.g. 1013.25hPa, the altitude in meters can be calculated with the international barometric formula: p altitude = 44330 * 1 - p0 1 5.
Data sheet BMP085 Page 16 4. I²C Interface • • • I²C is a digital two wire interface Clock frequencies up to 3.4mBit/sec (I²C standard, fast and high-speed mode supported) SCL and SDA needs a pull-up resistor, typ. 4.7 kOhm to VDDD (one resistor each for all the I²C bus) The I2C bus is used to control the sensor, to read calibration data from the E2PROM and to read the measurement data when A/D conversion is finished. SDA (serial data) and SCL (serial clock) have open-drain outputs.
Data sheet BMP085 Page 17 4.2 Device and register address The BMP085 module address is shown below. The LSB of the device address distinguishes between read (1) and write (0) operation, corresponding to address 0xEF (read) and 0xEE (write). A7 1 A6 1 A5 1 A4 0 A3 1 A2 1 A1 1 W/R 0/1 There is an easy way to connect two BMP085 to the same I2C bus: You can use the XCLR input of BMP085 to set one BMP085 part silent while you communicate with the other BMP085 part via I2C and vice versa.
Data sheet BMP085 Page 18 4.4 Start temperature and pressure measurement The timing diagrams to start the measurement of the temperature value UT and pressure value UP are shown below. After start condition the master sends the device address write, the register address and the control register data. The BMP085 sends an acknowledgement (ACKS) every 8 data bits when data is received. The master sends a stop condition after the last ACKS.
Data sheet BMP085 Page 19 4.5 Read A/D conversion result or E²PROM data To read out the temperature data word UT (16 bit), the pressure data word UP (16 to 19 bit) and the E2PROM data proceed as follows: After the start condition the master sends the module address write command and register address.
Data sheet BMP085 Page 20 5. Package 5.1 Pin configuration Picture shows the device in top view. Device pins are shown here transparently only for orientation purposes. Figure 8: Pin configuration Table 7: Pin configuration Pin No.
Data sheet BMP085 Page 21 5.2 Outline dimensions The sensor housing is a standard 8-pin lead-less chip carrier (LCC8) ceramic package. Its dimensions are 5.0mm x 5.0mm (±0.25mm) x 1.2mm (±0.12mm). Package weight is approximately 0.09grams. Note: All dimensions are in mm. 5.2.1 Top view Device pins are shown here transparently only for orientation purposes. Figure 9: Top view BST-BMP085-DS000-06 | Revision 1.
Data sheet BMP085 Page 22 5.2.2 Top view with lid Figure 10: Top view with lid 5.2.3 Side view with lid Figure 11: Side view with lid 5.3 Device marking The device lid shows the following laser-marking: Pin 1 identifier Date code Bosch logo / vent hole / last 3 digits of part ID (TTN) Lot ID The vent hole (diameter 0.5mm) is in the center of the lid, between the Bosch logo and the part ID code (144). BST-BMP085-DS000-06 | Revision 1.
Data sheet BMP085 Page 23 5.4 Tape on reel Number of parts per reel: 3,000 Orientation of the parts inside the reel is according to EN60286-3. Carrier tape material: Conductive polystyrene C 100, 103 – 106 Ohm/sq. Dimensions are in mm: A0 B0 K0 P W t = = = = = = 5.30 ± 0.10 5.30 ± 0.10 2.10 ± 0.10 8.00 ± 0.10 12.00 +0.30 / -0.10 0.30 ± 0.05 The bars between the cavities are embossed about 0.2mm into the direction of K0. All other dimensions and tolerances follow the EIA 481 standard.
Data sheet BMP085 Page 24 5.5 Printed circuit board (PCB) design Figure 12: Recommended PCB design (top view) 5.6 Moisture sensitivity level and soldering The BMP085 is classified MSL 1 (moisture sensitivity level) according to IPC/JEDEC standards J-STD-020D and J-STD-033A. The device can be soldered Pb-free with a peak temperature of 260°C for 20 to 40 sec. The minimum height of the solder after reflow shall be at least 50μm.
Data sheet BMP085 Page 25 5.7 RoHS compliancy The BMP085 sensor meets the requirements of the EC directive "Restriction of hazardous substances (RoHS)", please refer also to: "Directive 2002/95/EC of the European Parliament and of the Council of 27 January 2003 on the restriction of the use of certain hazardous substances in electrical and electronic equipment". The BMP085 sensor is also halogen-free. Please contact your Bosch Sensortec representative for the corresponding analysis report. 5.
Data sheet BMP085 Page 26 6. Legal disclaimer 6.1 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.
Data sheet BMP085 Page 27 7. Document history and modifications Rev. No 0.1 0.2 0.3 1.0 1.1 1.2 1.3 Chapter Description of modifications/changes First edition for description of serial production material Noise data update, peak current added, several minor changes 1 Update peak current, typo correction 1 Changed VDDA to VDD and VDDD to VDDIO 3.5 Updated flow diagram 4 New comment on floating XCLR 4.1 Added details on start-up time 5.
