MS5540C TEC | Alldatasheet
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SENSOR SOLUTIONS ///MS5540C Page 1 09/2015 MS5540C Miniature Barometer Module SPECIFICATIONS 10 - 1100 mbar absolute pressure range 6 coefficients for software compensation stored on-chip Piezoresistive silicon micromachined sensor Integrated miniature pressure sensor 6.2 x 6.4 mm 16 Bit ADC 3-wire serial interface 1 system clock line (32.768 kHz) Low voltage and low power consumption The MS5540C is a SMD-hybrid device including a precision piezoresistive pressure sensor and an ADC-Interface IC. It is a miniature version of the MS5534C barometer/altimeter module and provides a 16 Bit data word from a pressure and temperature dependent voltage. MS5540C is a low power, low voltage device with automatic power down (ON/OFF) switching. A 3-wire interface is used for all communications with a micro-controller. Compared to MS5534A the pressure range (measurement down to 10 mbar) has been improved. The MS5540C is fully software compatible to the MS5534C and previous versions of MS5540. In addition, the MS5540C is from its outer dimensions compatible to the MS54XX series of pressure sensors. Compared to the previous version the ESD sensitivity level has been improved to 4kV on all pins. The gel protection of the sensor provides a water protection sufficient for 100 m waterproof watches without any additional protection.
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 2
FEATURES
Resolution 0.1 mbar Supply voltage 2.2 V to 3.6 V Low supply current < 5 µA Standby current < 0.1 µA -40°C to +85°C operation temperature No external components required
APPLICATIONS
Mobile altimeter / barometer systems Weather control systems Adventure or multi-mode watches GPS receivers BLOCK DIAGRAM VDD GND MCLK SCLK DOUT DIN Input MUX ADC Digital Interface Memory (PROM) 64 bits SENSOR SGND +IN -IN dig. Filter Sensor Interface IC Fig. 1: Block diagram MS5540C
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 3 PIN CONFIGURATION Fig. 2: Pin configuration of MS5540C Pin Name Pin Type Function SCLK 1 I Serial data clock GND 2 G Ground PV (1) 3 N Negative programming voltage PEN (1) 4 I Programming enable VDD 5 P Positive supply voltage MCLK 6 I Master clock (32.768 kHz) DIN 7 I Serial data input DOUT 8 O Serial data output NOTE 1) Pin 3 (PV) and Pin 4 (PEN) are only used by the manufacturer for calibration purpo ses and should not be connected. ABSOLUTE MAXIMUM RATINGS Parameter Symbol Conditions Min Max Unit Notes Supply voltage VDD Ta = 25 °C -0.3 4 V Storage temperature TS -40 +85 °C 1 Overpressure P Ta = 25 °C 10 bar 2 NOTES 1) Storage and operation in an environment of dry and non-corrosive gases. 2) The MS5540C is qualified referring to the ISO 2281 standard and can withstan d an absolute pressure of 11 bar in salt water or 100 m water respectively.
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 4 RECOMMENDED OPERATING CONDITIONS (Ta = 25 °C, VDD = 3.0 V unless noted otherwise) Parameter Symbol Conditions Min Typ Max Unit Operating pressure range p 10 1100 mbar abs. Supply voltage VDD 2.2 3.0 3.6 V Supply current, average (1) during conversion (2) standby (no conversion) Iavg Isc Iss VDD = 3.0 V 0.1 µA mA µA Current consumption into MCLK (3) MCLK = 32.768 kHz 0.5 µA Operating temperature range T -40 +85 °C Conversion time tconv MCLK = 32.768 kHz 35 ms External clock signal (4) MCLK 30.000 32.768 35.000 kHz Duty cycle of MCLK 40/60 50/50 60/40 % Serial data clock SCLK 500 kHz NOTES 1) Under the assumption of one conversion every second. Conversion means either a pressure or a temperature measurement started by a command to the serial interface of MS5540C. 2) During conversion the sensor will be switched on and off in order to reduce power consumption; th e total on time within a conversion is about 2 ms. 3) This value can be reduced by switching off MCLK while MS5540C is in standby mode. 4) It is strongly recommended that a crystal oscillator be used because the device is sensi tive to clock jitter. A square-wave form of the clock signal is a must.
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 5
ELECTRICAL CHARACTERISTICS
Parameter Symbol Conditions Min Typ Max Unit Input High Voltage VIH 80% VDD 100% VDD V Input Low Voltage VIL 0% VDD 20% VDD V Signal Rise Time tr 200 ns Signal Fall Time tf 200 ns DIGITAL OUTPUTS Parameter Symbol Conditions Min Typ Max Unit Output High Voltage VOH Isource = 0.6 mA 80% VDD 100% VDD V Output Low Voltage VOL Isink = 0.6 mA 0% VDD 20% VDD V Signal Rise Time tr 200 ns Signal Fall Time tf 200 ns AD-CONVERTER Parameter Symbol Conditions Min Typ Max Unit Resolution 16 Bit Linear Range 4'000 40'000 LSB Conversion Time MCLK = 32.768 kHz 35 ms INL Within linear range -5 +5 LSB
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 6 PRESSURE OUTPUT CHARACTERISTICS With the calibration data stored in the interface IC of the MS5540C, the following characteristics can be achieved: (VDD = 3.0 V unless noted otherwise) Parameter Conditions Min Typ Max Unit Notes Resolution 0.1 mbar 1 Absolute Pressure Accuracy p =750 .. 1100 mbar Ta = 25°C -1.5 +1.5 mbar 2 Relative Pressure Accuracy p =750 .. 1100 mbar Ta = 25°C -0.5 +0.5 mbar 3 Relative Pressure Error over Temperature T = 0 .. +50°C p =300 .. 1000 mbar -1 +1 mbar 4 T = -40 .. +85°C p =300 .. 1000 mbar -2 +5 mbar 4 Long-term Stability 12 months -1 mbar 5 Maximum Error over Supply Voltage VDD = 2.2 .. 3.6 V p = const. -1.6 1.6 mbar NOTES 1) A stable pressure reading of the given resolution requires taking the average of 2 to 4 subsequent pressure values due to noise of the ADC. 2) Maximum error of pressure reading over the pressure range. 3) Maximum error of pressure reading over the pressure range after offset adjustment at one pressure point. 4) With the second-order temperature compensation as described in Section "FUNCTION". See ne xt section for typical operating curves. 5) The long-term stability is measured with non-soldered devices. TEMPERATURE OUTPUT CHARACTERISTICS This temperature information is not required for most applications, but it is necessary to allo w for temperature compensation of the output. (VDD = 3.0 V unless noted otherwise) Parameter Conditions Min Typ Max Unit Notes Resolution 0.005 0.01 0.015 °C Accuracy T = 20 °C -0.8 0.8 °C Maximum Error over Supply Voltage NOTES 1) With the second-order temperature compensation as described in Section "FUNCTION". See nex t section for typical operating curves. 2) At Ta = 25 °C.
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 7 TYPICAL PERFORMANCE CURVES ADC-value D1 vs Pressure (typical) 6000 8000 10000 12000 14000 16000 18000 20000 22000 0 100 200 300 400 500 600 700 800 900 1000 1100 Pressure (mbar) ADC-value D1 (LSB) -40°C 25°C 85°C ADC-value D2 vs Temperature (typical) 15000 20000 25000 30000 35000 40000 -40 -20 0 20 40 60 80 Temperature (°C) ADC-value D2 (LSB) Absolute Pressure Accuracy after Calibration, 2nd order compensation 0 100 200 300 400 500 600 700 800 900 1000 1100 Pressure (mbar) Pressure error (mbar) 85°C 60°C 25°C 0°C -40°C
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 8 Temperature Error Accuracy vs temperature (typical) -40 -20 0 20 40 60 80 Temperature (°C) Temperature error (°C) Temperature error (standard calculation) Temperature error (with 2nd order calculation) Pressure Error Accuracy vs temperature (typical) -40 -20 0 20 40 60 80 Temperature (°C) Pressure error (mbar) Perror(1000,1st order) Perror(1000,2nd order) Perror(800,1st order) Perror(800,2nd order) Perror(300,1st order) Perror(300,2nd order)
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 9 Pressure error vs supply voltage (typical) -0.8 -0.6 -0.4 -0.2 0.2 0.4 0.6 0.8 Voltage (V) Pressure error (mbar) 1000mbar 800mbar 300mbar Temperature error vs supply voltage (typical) -0.15 -0.1 -0.05 0.05 0.1 0.15 Voltage (V) Temperature error (°C)
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 10 FUNCTION GENERAL The MS5540C consists of a piezo-resistive sensor and a sensor interface IC. The main function of the MS5540C is to convert the uncompensated analogue output voltage from the piezo-resistive pr essure sensor to a 16-bit digital value, as well as providing a 16-bit digital value for the temperature of the sensor. Measured pressure (16-bit) “D1” Measured temperature (16-bit) “D2” As the output voltage of a pressure sensor is strongly dependent on temperature and process tolerances, it is necessary to compensate for these effects. This compensation procedure must be performed by software using an external microcontroller. For both pressure and temperature measurement the same ADC is used (sigma delta converter):
- for the pressure measurement, the differential output voltage from the pressure sensor is converted
- for the temperature measurement, the sensor bridge resistor is sensed and converted During both measurements the sensor will only be switched on for a very short tim e in order to reduce power consumption. As both, the bridge bias and the reference voltage for the ADC are derived from VDD, the digital output data is independent of the supply voltage. FACTORY CALIBRATION Every module is individually factory calibrated at two temperatures and t wo pressures. As a result, 6 coefficients necessary to compensate for process variations and temperature variations are calculated and stored in the 64-bit PROM of each module. These 64-bit (partitioned into four words of 16-bit) must be read by the microcontroller software and used in the program converting D1 and D2 into compensated pressure and temperature values. PRESSURE AND TEMPERATURE MEASUREMENT The sequence of reading pressure and temperature as well as of performing the software compensation is depicted in Fig. 3 and Fig. 5. First Word1 to Word4 have to be read through the serial interface. This can be done once af ter reset of the microcontroller that interfaces to the MS5540C. Next, the compensation coefficients C1 to C6 are extracted using bit-wise logical- and shift-operations (refer to Fig. 4 for the bit-pattern of Word1 to Word4) . For the pressure measurement, the microcontroller has to read the 16-bit values for pressure (D1) and temperature (D2) via the serial interface in a loop (for instance every second). Then, the compensated press ure is calculated out of D1, D2 and C1 to C6 according to the algorithm in Fig. 3 (possibly using quadratic tempe rature compensation according to Fig. 5). All calculations can be performed with signed 16-bit var iables. Results of multiplications may be up to 32-bit long (+sign). In the flow according to Fig. 3 a division follows each multiplication. This division can be performed by bit-wise shifting (divisors are to t he power of 2). It is ensured that the results of these divisions are less than 65536 (16 bit). For the timing of signals to read out Word1 to Word4, D1, and D2 please refer to the paragraph “Serial Interface". Sensor Word 1..4 Calculation in external micro- controller Pressure Temperature
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 11 System initialisation Pressure and temperature measurement Example: Word1, Word2, Word3 and Word4 (4x16 Bit) D1 = 16460 D2 = 27856 Start Convert calibration data into coefficients: (see bit pattern of Word1-Word4) Read calibration data (factory calibrated) from PROM of MS5540C Read digital pressure value from MS5540C D1 (16 Bit) Read digital temperature value from MS5540C Display pressure and temperature value Basic equations: Calculate calibration temperature UT1 = 8*C5+20224 Calculate temperature compensated pressure Difference between actual temperature and reference temperature: dT = D2 - UT1 Actual temperature: TEMP = 200 + dT*(C6+50)/210 (0.1°C resolution) Calculate actual temperature D2 (16 Bit) SENST1 OFFT1 TCS TCO Tref TEMPSENS C1: Pressure sensitivity (15 Bit) C2: Pressure offset (12 Bit) C3: Temperature coefficient of pressure sensitivity (10 Bit) C4: Temperature coefficient of pressure offset (10 Bit) C5: Reference Temperature (11 Bit) C6: Temperature coefficient of the temperature (6 Bit) (Refer to application note AN516 for limits of coefficients and calculated results) Word1 = 46940 Word2 = 40217 Word3 = 25172 Word4 = 47212 C1 = 23470 C2 = 1324 C3 = 737 C4 = 393 C5 = 628 C6 = 25 dT(D2) = D2 - Tref TEMP(D2) = 20°+dT(D2)*TEMPSENS Offset at actual temperature: Sensitivity at actual temperature: SENS = C1 + (C3*dT)/210 + 24576 X = (SENS * (D1-7168))/214 - OFF Temperature compensated pressure: P = X*10/25 + 250*10 (0.1 mbar resolution) OFF(D2) = OFFT1+TCO*dT(D2) SENS(D2) = SENST1+TCS*dT(D2) P(D1,D2) = D1*SENS(D2)-OFF(D2) dT = 2608 TEMP = 391 = 39.1 °C OFF = 5220 SENS = 49923 X = 23093 P = 9716 = 971.6 mbar UT1 = 25248 Fig. 3: Flow chart for pressure and temperature reading and software compensation
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 12 NOTES 1) Readings of D2 can be done less frequently, but the display w ill be less stable in this case. 2) For a stable display of 1 mbar resolution, it is recommended to display the average of 8 s ubsequent pressure values. C1 (15 Bit) C5/I
1 Bit
Word1 DB14 DB13 DB12 DB11 DB10 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 DB10 C5/II (10 Bit) C6 (6 Bit) Word2 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 DB5 DB4 DB3 DB2 DB1 DB0 C4 (10 Bit) C2/I (6 Bit) Word3 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 DB11 DB10 DB9 DB8 DB7 DB6 C3 (10 Bit) C2/II (6-Bit) Word4 DB9 DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 DB5 DB4 DB3 DB2 DB1 DB0 Fig. 4: Arrangement (Bit-pattern) of calibration data in Word1 to Word4 SECOND-ORDER TEMPERATURE COMPENSATION In order to obtain full temperature accuracy over the whole temperature range, it is recomm ended to compensate for the non-linearity of the output of the temperature sensor. This can be achie ved by correcting the calculated temperature and pressure by a second order correction factor. The second-order factors are calculated as follows : Fig. 5: Flow chart for calculating the temperature and pressure to the optimum accuracy. No correction T2 = 0 P2 = 0 High Temperatures P2 = T2 * (P - 10000)/213 TEMP < 200 yes Calculate pressure and temperature TEMP = TEMP – T2 P = P – P2 Low Temperatures TEMP > 450 yes 200 TEMP 450 yes
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 13 SERIAL INTERFACE The MS5540C communicates with microprocessors and other digital systems via a 3-wire synchronous serial interface as shown in Fig. 1. The SCLK (Serial clock) signal initiates the communication and synchronizes the data transfer with each bit being sampled by the MS5540C on the rising edge of S CLK and each bit being sent by the MS5540C on the rising edge of SCLK. The data should thus be sampled by the microcontroll er on the falling edge of SCLK and sent to the MS5540C with the falling edge of SCLK. The SCLK-signal is generated by the microprocessor’s system. The digital data provided by the MS5540C on the DOUT pin is either the conversion result or the software calibration data. In addition, the signal DOUT (Data out) is also us ed to indicate the conversion status (conversion-ready signal, see below). The selection of the output data is done by sending the corresponding instruction on the pin DIN (Data input). Following is a list of possible output data instructions: Conversion start for pressure measurement and ADC- data-out “D1” (Figure 6a) Conversion start for temperature measurement and ADC- data-out “D2” (Figure 6b) Calibration data read-out sequence for Word1 (Figure 6c) Calibration data read-out sequence for Word2 (Figure 6d) Calibration data read-out sequence for Word3 (Figure 6c) Calibration data re ad-out sequence for Word4 (Figure 6d) RESET sequence (Figure 6e) Every communication starts with an instruction sequence at pin DIN. Fig. 6 shows the timing diagrams for the MS5540C. The device does not need a ‘Chip select’ signal. Instead there is a START sequence (3-Bit high) before each SETUP sequence and STOP sequence (3-Bit low) after each SETUP s equence. The SETUP sequence consists in 4-Bit that select a reading of pressure, temperature or calibration data. In c ase of pressure- (D1) or temperature- (D2) reading the module acknowledges the start of a conversion by a l ow to high transition at pin DOUT. Two additional clocks at SCLK are required after the acknowledge signal. Then S CLK is to be held low by the microcontroller until a high to low transition on DOUT indicates the end of the conversion. This signal can be used to create an interrupt in the microcontroller. The mic rocontroller may now read out the 16 bit word by giving another 17 clocks on the SLCK pin. It is possible to interru pt the data READOUT sequence with a hold of the SCLK signal. It is important to always read out the last conversion result before starting a new conversion. The RESET sequence is special as the module in any state recognizes its unique pattern. By consequence, it can be used to restart if synchronization between the microcontroller and the MS5540C has been lost. This sequence is 21-bit long. The DOUT signal might change during that sequence (see Fig. 6e) . It is recommended to send the RESET sequence before each CONVERSION sequence to avoid hanging up the protocol perm anently in case of electrical interference. sequence: START+P-measurement SCLKDOUTDIN Bit7 Conversion start for pressure measurement and ADC-data-out "D1": end of conversion Bit6Bit5Bit4Bit3Bit2Bit1Bit0 conversion (33ms) DB7 ADC-data out MSB ADC-data out LSB Bit8 Bit9 Start-bit Stop-bit DB6 DB5 DB4 DB3 DB2 DB1 DB0 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 start of conversion Setup-bits Fig. 6a: D1 ACQUISITION sequence
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 14 sequence: START+T-measurement SCLKDOUTDIN Bit7 Conversion start for temperature measurement and ADC-data-out "D2": end of conversion Bit6Bit5Bit4Bit3Bit2Bit1Bit0 conversion (33ms) Bit8 Bit9 Start-bit Stop-bitSetup-bits start of conversion DB7 ADC-data out MSB ADC-data out LSB DB6 DB5 DB4 DB3 DB2 DB1 DB0 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 Fig. 6b: D2 ACQUISITION sequence sequence: coefficient read + address SCLKDOUTDIN Bit7 Calibration data read out sequence for word 1/ word 3: Bit6Bit5Bit4Bit3Bit2Bit1Bit0 DB7 coefficient-data out MSB coefficient-data out LSB Bit8 Bit9 Start-bit Stop-bit DB6 DB5 DB4 DB3 DB2 DB1 DB0 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 Bit10Bit11 address word 1 address word 3 Setup-bits Fig. 6c: Word1, Word3 READING sequence address word 2 address word 4 sequence: coefficient read + address SCLKDOUTDIN Bit7 Calibration data read out sequence for word 2/ word 4: Bit6Bit5Bit4Bit3Bit2Bit1Bit0 DB7 coefficient-data out MSB coefficient-data out LSB Bit8 Bit9 Start-bit Stop-bit DB6 DB5 DB4 DB3 DB2 DB1 DB0 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0 Bit10Bit11 Setup-bits Fig. 6d: W2, W4 READING sequence sequence: RESET SCLKDOUTDIN Bit7 RE SE T - sequence: Bit6Bit5Bit4Bit3Bit2Bit1Bit0 Bit8 Bit9Bit10Bit11 Bit12Bit13Bit14Bit15Bit16Bit17Bit18Bit19Bit20 Fig. 6e: RESET sequence (21 bit)
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 15
APPLICATION INFORMATION
The advantage for this combination of a sensor with a directly adapted integrated c ircuit is to save other external components and to achieve very low power consumption. The main application field for this system includes portable devices with battery supply, but its high accuracy and resolution m ake it also suited for industrial and automotive applications. The possibility to compensate the sensor with software allo ws the user to adapt it to his particular application. Communication between the MS5540C and the widely ava ilable microcontrollers is realised over an easy- to-use 3-wire serial interface. Customers may select which microcontroller sy stem to be used, and there are no specific standard interface cells required, which may be of interest for specially designed 4 Bit- microcontroller applications. CALIBRATION The MS5540C is factory calibrated. The calibration data is stored inside the 64 bit PROM memor y. SOLDERING Please refer to the application note AN808 for all soldering issues. HUMIDITY, WATER PROTECTION The version MS5540-CM carries a metal protection cap filled with silicone ge l for enhanced protection against humidity. The properties of this gel ensure function of the sensor even when in direc t water contact. This feature can be useful for waterproof watches or other applications, where direct water contact can not be avoided. Nevertheless the user should avoid drying of hard materials like for example salt particles on the silicone gel surface. In this case it is better to rinse with clean water afterwards. Special care has to be taken to not mechanically damage the gel. Damaged gel could lead to air entrapment and consequently to unstable sensor signal, especially if the damage is close to the sensor surface. The metal protection cap is fabricated of special anticorrosive stainless steel in order to avoid any corrosive battery effects inside the final product. The MS5540CM was qualified referring to the ISO Standard 2281 and can withstand a pressure of 11 bar in salt water. The concentration of the sea water used for the qua lification is 41 g of see salt for 1 litre of DI water. For underwater operations as specified in ISO Standard 2281 it is important to seal the sensor with a rubber O-ring around the metal cap. Any salt water coming to the contact side (ceramic and pads) of the sensor could lead to permanent damage. Especially for "water-resistant 100 m" watches it is r ecommended to provide a stable mechanical pusher from the backside of the sensor. Otherwise the overpressure might push the sensor backwards and even bend the electronic board on which the sensor is mounted. LIGHT SENSITIVITY The MS5540C is protected against sunlight by a layer of white gel. It is, however, important to note that the sensor may still be slightly sensitive to sunlight, especially to infrared light sources. This is due to the strong photo effect of silicon. As the effect is reversible there will be no damage, but the user h as to take care that in the final product the sensor cannot be exposed to direct light during operation. This can be ac hieved for instance by placing mechanical parts with holes in such that light cannot pass.
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 16 CONNECTION TO PCB The package outline of the module allows the use of a flexible PCB to connect it. This can be important for applications in watches and other special devices, and will also reduce mechanical stress on the device. For applications subjected to mechanical shock, it is recommended to enhance the mec hanical reliability of the solder junctions by covering the rim or the corners of MS5540C's ceramic substrate with glue or Globtop-like material. DECOUPLING CAPACITOR Particular care must be taken when connecting the device to power supply. A 47 F tantalum capacitor must be placed as close as possible of the MS5540C's VDD pin. This capacitor will stabili ze the power supply during data conversion and thus, provide the highest possible accuracy. APPLICATION EXAMPLE: ALTIMETER SYSTEM USING MS5540C MS5540C is a circuit that can be used in connection with a microcontrol ler in diving computer applications. It is designed for low-voltage systems with a supply voltage of 3V, particularly i n battery applications. The MS5540C is optimised for low current consumption as the AD-converter clock (MCLK) can us e the 32.768 kHz frequency of a standard watch crystal, which is supplied in most portable watch systems. For applications in altimeter systems MEAS Switzerland can deliver a simple formula to calculate the altitude, based on a linear interpolation, where the number of interpolation points influences the accuracy of the f ormula. Figure 7: Demonstration of MS5540C in a mobile altimeter 4/8bit-Microcontroller LCD-Display EEPROM Keypad MS5540C SCLK DIN DOUT MCLK XTAL1 XTAL2 32.768 kHz optional VDD GND VDD GND 3V-Battery 47µF Tantal
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 17 RECOMMENDED PAD LAYOUT Pad layout for bottom side of MS5540C soldered onto printed circuit board. Fig. 8: Layout for bottom side
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 18 DEVICE PACKAGE OUTLINES Fig. 9: Device package outlines of MS5540-C
Miniature Barometer Module SENSOR SOLUTIONS ///MS5540C 09/2015 Page 19 ASSEMBLY MECHANICAL STRESS It is recommended to avoid mechanical stress on the PCB on which the sensor i s mounted. The thickness of the PCB should not be below 1.6 mm. A thicker PCB is stiffer creating less s tress on the soldering contacts. For applications where mechanical stress cannot be avoided (for example ultrasound welding of the case or thin PCB’s in watches) please fix the sensor with drops of low stress epoxy (for example Hysol FP-440 1). MOUNTING The MS5540C can be placed with automatic Pick & Place equipment using vacuum nozzles. It will not be damaged by the vacuum. Due to the low stress assembly the sensor does not show pressure hysteresis effects. Special care has to be taken to not touch the protective gel of the sensor during the assembly. The MS5540C can be mounted with the cap down or the cap looking upwards. In both cases it is important to solder all contact pads. The Pins PEN and PV shall be left open or connected to V DD. Do not connect the Pins PEN and PV to GND! SEALING WITH O-RING In products like outdoor watches the electronics must be protected against direct water or humidity. For those products the MS5540-CM provides the possibility to seal with an O-ring. The protective cap of the MS5540CM is made of special anticorrosive stainless steel with a polished surface. In addition to this the MS5540CM is filled with silicone gel covering the sensor and the bonding wires. The O-ring (or O-rings) shall be placed at the outer diameter of the metal cap. This method avoids mechanical stress because the sensor can move in vertical di rection. CLEANING The MS5540C has been manufactured under cleanroom conditions. Each device has b een inspected for the homogeneity and the cleanness of the silicone gel. It is therefore recommended to assemble the sensor under class 10’000 or better conditions. Should this not be possible, it is recommended to protect the sensor opening during assembly from entering particles and dust. To avoid cleaning of the PCB, solde r paste of type “no -clean” shall be used. Cleaning might damage the sensor! ESD PRECAUTIONS The electrical contact pads are protected against ESD up to 4 kV HBM (human body model). It is therefore essential to ground machines and personal properly during assembly and handling of the d evice. The MS5540C is shipped in antistatic transport boxes. Any test adapters or production transport boxes used during the assembly of the sensor shall be of an equivalent antistatic material.
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ORDERING INFORMATION
Part Number / Art. Number Product MEAS Production Site Delivery Form 325540009-00 MS5540-CM Miniature Barometer Module Switzerland Tube 325540009-50 MS5540-CM Miniature Barometer Module Switzerland Tape&Reel TOP-UP 325540009-08 MS5540-CM Miniature Barometer Module China TE.com/sensorsolutions Measurement Specialties, Inc., a TE Connectivity company. Measurement Specialties, TE Connectivity, TE Connectivity (logo) and EVERY CONNECTION COUNTS are trademarks. All other logos, products and/or company names referred to herein might be trademarks of their respective owners. The information given herein, including drawings, illustrations and schematics which are intended for illustration purposes only, is believe d to be reliable. However, TE Connectivity makes no warranties as to its accuracy or completeness and disclaims any liability in connection with its use. TE Connectivity‘s obligation s shall only be as set forth in TE Connectivity‘s Standard Terms and Conditions of Sale for this product and in no case will TE Connectivity be liable for any incidental, indirect or consequential damages arising out of the sale, resale, use or misuse of the product. Users of TE Connectivity products should make their own evaluation to determine the suitability of each such product for the specific application. © 2015 TE Connectivity Ltd. family of companies All Rights Reserved. DA5540C_008 0005540C1193 ECN2224 NORTH AMERICA Measurement Specialties, Inc., a TE Connectivity Company
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