Pressure Freescale Semiconductor MPL115A1 Rev 3, 08/2009 Miniature SPI Digital Barometer The MPL115A1 is an absolute pressure sensor with digital output for low cost applications. A miniature 5 x 3 x 1.2 mm LGA package ideally suits it for portable electronics and space constrained applications. Low current consumptions of 5 μA during Active mode and 1 μA during Shutdown (Sleep) mode target battery and other low-power applications. A wide operating temperature range from -40°C to +105°C fits demanding environmental requirements. MPL115A1 employs a MEMS pressure sensor with a conditioning IC to provide accurate pressure measurement from 50 to 115 kPa. An integrated ADC provides digitized temperature and pressure sensor outputs via a SPI port. Calibration Data is stored in internal ROM. Utilizing raw sensor output, the host microcontroller executes a compensation algorithm to render Compensated Absolute Pressure with 1 kPa accuracy. MPL115A1 50 to 115 kPa Application Examples • • • • • • • The MPL115A1 pressure sensor’s small form factor, low power capability, precision, and digital output optimize it for barometric measurement applications. Features Barometry (portable and desk-top) Altimeters Weather Stations Hard Disk-Drives (HDD) Industrial Equipment Health Monitoring Air Control Systems • Digitized pressure and temperature information together with programmed calibration coefficients for host micro use. • Factory Calibrated • 50 kPa to 115 kPa Absolute Pressure • 1 kPa Accuracy • 2.375 V to 5.5 V Supply • Integrated ADC • SPI Interface • Monotonic Pressure and Temperature Data Outputs • Surface Mount RoHS Compliant Package ORDERING INFORMATION Device Name MPL115A1T1 Package Options Case No. Tape & Reel 2015 # of Ports None Single Pressure Type Dual Gauge Differential • Absolute Digital Interface • SPI LGA PACKAGE Pin Description MPL115A1 5.0 mm X 3.0 mm X 1.2 mm MAX VDD 1 8 SCLK CAP 2 7 DIN GND 3 6 DOUT SHDN 4 5 CS PIN NAME 1 VDD VDD Power Supply Connection. 2 CAP External Capacitor 3 GND Ground 4 SHDN 5 CS 6 DOUT 7 DIN DIN: Serial data input. 8 SCLK SPI Serial Clock Input. PIN CONNECTIONS © Freescale Semiconductor, Inc., 2009. All rights reserved. FUNCTION Shutdown (Sleep): Connect to GND to disable the device. When in shut down the part draws < 1μA supply current CS: SPI Chip Select line. DOUT: Serial data output. Pressure Maximum Ratings Voltage (with respect to GND unless otherwise noted) VDD .............................................................................................................................. -0.3 V to +5.5 V SCLK, CS, DIN, DOUT ................................................................................................. -0.3 V to VDD+0.3 V Operating Temperature Range .................................................................................... -40°C to +105°C Storage Temperature Range........................................................................................ -40°C to +125°C Overpressure ............................................................................................................... 1000 kPa Operating Characteristics (VDD = 2.375 V to 5.5 V, TA = -40°C to +105°C, unless otherwise noted. Typical values are at VDD = 3.3 V, TA = +25°C. Ref Parameters Symbol 1 Operating Supply Voltage VDD 2 Supply Current IDD Conditions Min Typ Max Units 2.375 3.3 5.5 V Shutdown (SHDN = GND) — — 1 μA Standby — 3.5 10 μA Average – at one measurement per second — 5 — μA Pressure Sensor 3 Range 50 — 115 kPa 4 Resolution — 0.15 — kPa 5 Accuracy -20ºC to 85ºC — ±1 — kPa 6 Conversion Time (Start Pressure Convert) Time between start convert command and data available in the Pressure register — 0.6 0.7 ms -40 — 105 ºC tcp Temperature Sensor 7 Range 8 Conversion Time (Start Temperature Convert) tct Time between start convert command and data available in the Temperature register — 0.6 0.7 ms 9 Conversion Time (Start Both Convert) tcb Time between start convert command and data available in the Pressure and Temperature registers — 0.8 1 ms 10 Resolution Temperature ADC is 472 counts at 25ºC — -5.35 — counts/ºC (1) — — 8 MHz SPI Inputs: SCLK, CS, DIN 11 SCLK Clock Frequency fSCLK 12 Low Level Input Voltage VIL — — 0.3VDD V 13 High Level Input Voltage VIH 0.7VDD — — V V SPI Outputs: DOUT 14 15 Low Level Output Voltage High Level Output Voltage VOL1 At 3 mA sink current 0 — 0.4 VOL2 At 6 mA sink current 0 — 0.6 VDD – 0.4 V — — VOH1 At 3 mA source current V 1. Nominal maximum SPI clock frequency. MPL115A1 2 Sensors Freescale Semiconductor Pressure 1 μF VDD VDD ADDR Coefficient Storage ADDR CAP CAP 1 μF ADDR Diff Amp MUX SHDN ADC ADDR Pressure ADDR Temperature Temp Sensor SHDN SCLK SCLK DIN SPI Interface DIN μC Microcontroller DOUT DOUT CS CS GND GND Figure 1. Uncompensated Pressure Sensor Schematic Compensation The pressure compensation for MPL115A1 is based on a 2-dimensional, second order polynomial based on Microsystems mst_trimlib library. The 10-bit compensated pressure output, Pcomp, is calculated as follows: Pcomp = a0 + (b1 + c11*Padc + c12*Tadc) * Padc + (b2 + c22*Tadc) * Tadc Where: Padc is the 10-bit pressure output of the MPL115A1 ADC, Tadc is the 10-bit temperature output of the MPL115A1 ADC, a0 is the pressure offset coefficient, b1 is the pressure sensitivity coefficient, c11 is the pressure linearity (2nd order) coefficient, c12 is the coefficient for temperature sensitivity coefficient (TCS), b2 is the 1st order temperature offset coefficient (TCO), c22 is the 2nd order temperature offset coefficient. Ideally, Pcomp will produce a value of 0 with an input pressure of 50 kPa and will produce a full-scale value of 1023 with an input pressure of 115 kPa. MPL115A1 Sensors Freescale Semiconductor 3 Pressure Coefficient Bit-Width Specs The table below specifies the initial coefficient bit-width specs for the compensation algorithm. a0 b1 b2 c12 c11 c22 Total Coeff. Bits Total Bits 16 16 16 14 11 11 84 Sign Bits 1 1 1 1 1 1 Integer Bits 12 2 1 0 0 0 Fractional Bits 3 13 14 13 11 10 dec pt zero pad — — — 9 11 15 10-bit Output: Compensation Coefficient Specs Example Binary Format Definitions: 1. Sign = 0, Integer Bits = 8, Fractional Bits = 4 : Coeff = S I7 I6 I5 I4 I3 I2 I1 I0 . F3 F2 F1 F0 2. Sign = 1, Integer Bits = 4, Fractional Bits = 7 : Coeff = S I3 I2 I1 I0 . F6 F5 F4 F3 F2 F1 F0 3. Sign = 0, Integer Bits = 0, Fractional Bits = 6, dec pt zero pad = 2 : Coeff = S 0 . 0 0 F5 F4 F3 F2 F1 F0 4. Sign = 0, Integer Bits = 0, Fractional Bits = 5, dec pt zero pad = 3 : Coeff = S 0 . 0 0 0 F4 F3 F2 F1 F0 NOTE: Negative coefficients (Sign = 1) are coded in 2’s complement notation. Coefficient Address Map Address Coefficient $04 a0 MS Byte $05 a0 LS Byte $06 b1 MS Byte $07 b1 LS Byte $08 b2 MS Byte $09 b2 LS Byte $0A c12 MS Byte $0B c12 LS Byte $0C c11 MS Byte $0D c11 LS Byte $0E c22 MS Byte $0F c22 LS Byte For coefficients with less than 16 bits, the lower lsbs are zero. For example, c11 is 11 bits and is stored into 2 bytes as follows: c11 MS byte = c11[10:3] = [c11b10 , c11b9 , c11b8 , c11b7 , c11b6 , c11b5 , c11b4 , c11b3] NOTE: c11 LS byte = c11[2:0] & “00000” = [c11b2 , c11b1 , c11b0 , 0 , 0 , 0 , 0 , 0] MPL115A1 4 Sensors Freescale Semiconductor Pressure Solder Recommendations 1. Use SAC solder alloy (i.e., Sn-Ag-Cu) with a melting point of about 217°C. It is recommended to use SAC305 (i.e., Sn-3.0 wt.% Ag-0.5 wt.% Cu). 2. Reflow • • • • • • Ramp up rate: 2 to 3 C/s. Preheat flat (soak): 110 to 130s. Reflow peak temperature: 250°C to 260°C (depends on exact SAC alloy composition). Time above 217°C: 40 to 90s (depends on board type, thermal mass of the board/quantities in the reflow). Ramp down: 5 to 6 C/s. Using an inert reflow environment (with O2 level about 5 to 15 ppm). NOTE: The stress level and signal offset of the device also depends on the board type, board core material, board thickness and metal finishing of the board. Handling Recommendations It is recommended to handle the MPL115A Pressure Sensor with a vacuum pick and place tool. Sharp objects utilized to move the MPL115A Pressure Sensor increase the possibility of damage via a foreign object/tool into the small exposed port. The sensor die is sensitive to light exposure. Direct light exposure through the port hole can lead to varied accuracy of pressure measurement. Avoid such exposure to the port during normal operation. MPL115A1 Sensors Freescale Semiconductor 5 Pressure PACKAGE DIMENSIONS CASE 2015-02 ISSUE O LGA PACKAGE MPL115A1 6 Sensors Freescale Semiconductor Pressure PACKAGE DIMENSIONS CASE 2015-02 ISSUE O LGA PACKAGE MPL115A1 Sensors Freescale Semiconductor 7 How to Reach Us: Home Page: www.freescale.com Web Support: http://www.freescale.com/support USA/Europe or Locations Not Listed: Freescale Semiconductor, Inc. Technical Information Center, EL516 2100 East Elliot Road Tempe, Arizona 85284 1-800-521-6274 or +1-480-768-2130 www.freescale.com/support Europe, Middle East, and Africa: Freescale Halbleiter Deutschland GmbH Technical Information Center Schatzbogen 7 81829 Muenchen, Germany +44 1296 380 456 (English) +46 8 52200080 (English) +49 89 92103 559 (German) +33 1 69 35 48 48 (French) www.freescale.com/support Japan: Freescale Semiconductor Japan Ltd. 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