SCA610-E28H1A Datasheet SCA610-E28H1A SINGLE AXIS ACCELEROMETER WITH ANALOG INTERFACE The SCA610 accelerometer consists of a silicon bulk micro machined sensing element chip and a signal conditioning ASIC. The chips are mounted on a pre-molded package and wire bonded to appropriate contacts. The sensing element and ASIC are protected with silicone gel and lid. The sensor has 8 SMD legs (Gull-wing type). Applications Features • • • • • • • • Single +5 V supply Current consumption 2.5 mA typical Ratiometric output in relation to supply voltage (Vdd = 4.75 V...5.25 V) Enhanced failure detection features o Digitally activated, true self-test by proof mass deflection using electrostatic force o Memory parity check during power up, and self-test cycle. o Built in connection failure detection Digitally activated, true self-test by proof mass deflection using electrostatic force Wide load drive capability (max. 20 nF) True DC response Qualified according to AEC-Q100 standard SCA610 product family is targeted to automotive applications with high stability and reliability requirements. Typical applications include: • Electronic Stability Control (ESC) • Engine Vibration Measurement • Roll Over • Suspension • Inclination 5V supply Measurement circuitry Sensing element Gain & filtering EEPROM for calibration constants (32 bit, pari ty check ) Vout Digital self test input ASIC GND 4 programming lines for factory use only Figure 1. Functional block diagram. Murata Electronics Oy www.muratamems.fi Doc.nr. 82 1580 00 1/12 Rev.B SCA610-E28H1A Table of Contents SCA610-E28H1A single axis accelerometer with analog interface .................................... 1 FEATURES .................................................................................................................................... 1 APPLICATIONS .............................................................................................................................. 1 TABLE OF CONTENTS .................................................................................................................... 2 1. Electrical Specifications ............................................................................................ 3 1.1. 1.2. 1.3. 1.4. 1.5. 1.6. 1.7. ABSOLUTE MAXIMUM RATINGS............................................................................................ 3 PERFORMANCE CHARACTERISTICS ..................................................................................... 3 OFFSET AND SENSITIVITY CALIBRATION................................................................................ 4 ERROR CALCULATIONS ....................................................................................................... 4 SUPPLY VOLTAGE ............................................................................................................... 5 ELECTRICAL CONNECTION .................................................................................................. 6 TYPICAL PERFORMANCE CHARACHTERISTICS ...................................................................... 7 2. Functional description ............................................................................................... 8 2.1. 2.2. 2.3. 2.4. MEASURING DIRECTIONS .................................................................................................... 8 VOLTAGE TO ACCELERATION CONVERSION .......................................................................... 8 RATIOMETRIC OUTPUT ....................................................................................................... 8 SELFTEST AND FAILURE DETECTION MODES ......................................................................... 8 3. Mechanical Specification ........................................................................................ 10 3.1. DIMENSIONS ....................................................................................................................10 4. Application information............................................................................................ 11 4.1. 4.2. RECOMMENDED PCB LAY-OUT .........................................................................................11 REFLOW SOLDERING ........................................................................................................12 Murata Electronics Oy www.muratamems.fi Doc. nr. 82 1580 00 2/13 Rev.B SCA610-E28H1A 1. Electrical Specifications 1.1. Absolute Maximum Ratings Parameter Value Acceleration (powered or non-powered) 20 000 Units (1 g Supply voltage −0.3 to +7.0 V Voltage at input / output pins −0.3 to VDD + 0.3 V ESD HBM (Human Body Model) ±2 kV ESD CDM (Charged Device Model) ±500 middle pins V ±750 corner pins Temperature range (storage) −50 to +125 °C Temperature range (operating) −40 to +125 °C 1 1.2. Equals to drop from 1 meter on a concrete surface. Performance Characteristics VDD = 5.00 V and ambient temperature unless otherwise specified. KPCA) Parameter Condition Min. <CC> <CC> <CC> B. g V mA °C kΩ nF V V V V/g -100 0 +100 mg −40 °C...125 °C −125 0 +125 mg −40 °C...105 °C −4 0 +4 % −40 °C...125 °C +1g ... -1g range +1.7g ... -1.7g range end point fit −5 −20 -40 0 +5 +20 +40 % mg mg 20 −2 50 44 62 80 +2 3.9 5 10 80 Hz % % mVrms ms kΩ Linearity error A. 5.0 2.5 −40 °C...105 °C <SC> <SC> Units +1.7 5.25 4.0 +125 Offset Error (Output at 0 g) Sensitivity error Amplitude response −3 dB Ratiometric error Cross-axis sensitivity Output noise Start-up delay Self test pull down resistor (Internal) −1.7 4.75 Max. Vout to Vdd or Vss Vout to Vdd or Vss 20k from Vout to Vdd 20k from Vout to Vss @ room temperature @ room temperature <SC> Nominal Typ Measuring range Supply voltage Vdd Current consumption Operating temperature Resistive output load Capacitive load Min. output voltage; Vdd = 5 V Max. output voltage; Vdd = 5 V Offset (Output at 0 g) Sensitivity Vdd = 5 V; No load B) Vdd = 4.75 V...5.25 V @ room temperature From DC...4 kHz Reset and parity check −40 20 20 0.25 5.00 0 4.75 Vdd/2 1.2 (0.24*Vdd) CC= SC= Critical Characteristics. Must be 100% monitored during production Significant Characteristic. The process capability (Cpk) must be better than 1.33, which allows sample based testing. If process is not capable the part will be 100% tested Output has true DC response Murata Electronics Oy www.muratamems.fi Doc. nr. 82 1580 00 3/13 Rev.B SCA610-E28H1A 1.3. Offset and sensitivity calibration Vout offset is calibrated in 0g position: Offset = Vout (0 g ) [V] Nominal offset is Vdd/2: Offset nom = Vdd [V] 2 Sensitivity is calibrated as: Sensitivity = Vout (+ 1g ) − Vout (− 1g ) [V/g] 2g Nominal sensitivity is: Sensitivity nom = 1,2 [V/g] 1.4. Error calculations Total error is the allowed maximum error, which include partial error sources. Total error over lifetime is specified as a sum of offset and sensitivity errors: Total _ Error = Offset _ Error + Sensitivity _ Error [mg] Offset error is specified as: Vdd 2 [mg] Sensitivity Vout (0 g ) − Offset _ Error = Sensitivity error percent is specified as: Sensitivity _ Error % = [Vout (+ 1g ) − Vout (− 1g )] 2 g − Sensitivity nom × 100% Sensitivity nom Sensitivity error is specified as: Sensitivity _ Error = Murata Electronics Oy www.muratamems.fi [Vout − Vout (0 g )]× Sensitivity _ Error % Sensitivity Doc. nr. 82 1580 00 [mg] 4/13 Rev.B SCA610-E28H1A 1.5. Suppl y voltage Usage of external 100 nF power supply bypass capacitor is recommended. ASIC start-up should be tolerant to noise between Vdd and GND. Recommended power-up ramp is presented below. Parameter T1 T2 V1 V2 Min T0 + 0.1 µs −0.3 V 4.5 V Max T0 + 100 µs 0.5 V 5.5 V Supply voltage ramp at startup. supply voltage V2 V1 t T0 T1 T2 Figure 2. VDD Start-up sequence. Murata Electronics Oy www.muratamems.fi Doc. nr. 82 1580 00 5/13 Rev.B SCA610-E28H1A 1.6. Electrical Connection The following is minimum requirement for electrical interface to the SCA610. If over-voltage or reverse polarity protection is needed, please contact VTI Technologies Oy for application information. Usage of external minimum 100 nF power supply bypass capacitor is recommended. Maximum rise time of VDD is 100 ms. If self-test (Pin 6) is not used it should be left floating. Pins 1, 2, 3, and 5 are left floating. Vdd Vout 8 7 6 5 Min. 100nF SCA610 1 2 3 4 GND Figure 3. Electrical connection of SCA610 component. Pin # Pin Name 1 2 3 4 5 6 7 8 CLK C1 MODE GND PGM ST VOUT VDD Murata Electronics Oy www.muratamems.fi I/O Function Supply Negative supply voltage (VSS) Input Output Supply Self-test control Sensor output voltage Positive supply voltage (VDD) Doc. nr. 82 1580 00 Connection on PCB Float / Not connected Float / Not connected Float / Not connected Ground Float / Not connected Float when not used Measuring circuit input Vdd (+5V) 6/13 Rev.B SCA610-E28H1A 1.7. Typical Performance Charachteristics Typical offset and sensitivity temperature dependencies of the SCA610-E28H1A are presented in following diagrams. These results represent the typical performance of SCA610-E28H1A components. The mean value and 3 sigma limits (mean ± 3× standard deviation) and specification limits are presented in following diagrams. The 3 sigma limits represents 99.73% of the SCA610E28H1A population. Figure 5. Typical temperature dependency of offset. Figure 6. Typical temperature dependency of sensitivity. Murata Electronics Oy www.muratamems.fi Doc. nr. 82 1580 00 7/13 Rev.B SCA610-E28H1A 2. Functional description 2.1. Measuring directions - + + - -1 g position Vout,nom = 1.3 V 2.2. 0 g position Vout,nom = 2.5 V +1 g position Vout,nom = 3.7 V Voltage to acceleration conversion Analog output can be transferred to acceleration using the following equation for conversion: Acceleration = Vout − Vout (0 g ) [g] Sensitivity where: Vout(0g) = nominal output of the device at 0g position with 5 V supply voltage (ratiometric output), Sensitivity is the sensitivity of the device and Vout is the output of the sensor. 2.3. Ratiometric Output Ratiometric output means that the zero offset point and sensitivity of the sensor are proportional to the supply voltage. If the SCA6X0 supply voltage is fluctuating the SCA6X0 output will also vary. When the same reference voltage for both the SCA6X0 sensor and the measuring part (A/Dconverter) is used, the error caused by reference voltage variation is automatically compensated for. 2.4. Selftest and failure detection modes To ensure reliable measurement results the SCA6X0 has continuous interconnection failure and calibration memory validity detection. A detected failure forces the output signal close to power supply ground or VDD level, outside the normal output range. The calibration memory validity is verified by continuously running parity check for the control register memory content. In the case where a parity error is detected, the control register is automatically re-loaded from the EEPROM. If a new parity error is detected after re-loading data analog output voltage is forced to go close to ground level (<0.25 V). The SCA6X0 also includes a separate self test mode. The true self test simulates acceleration, or deceleration, using an electrostatic force. The electrostatic force simulates acceleration that is high enough to deflect the proof mass to the extreme positive position, and this causes the output signal to go to the maximum value. The self test function is activated by a separate on-off command on the self test input. Murata Electronics Oy www.muratamems.fi Doc. nr. 82 1580 00 8/13 Rev.B SCA610-E28H1A The self-test generates an electrostatic force, deflecting the sensing element’s proof mass, thus checking the complete signal path. The true self test performs following checks: • Sensing element movement check • ASIC signal path check • PCB signal path check • Micro controller A/D and signal path check The created deflection can be seen in analogue output. Self test can be activated applying logic”1” (positive supply voltage level) to ST pin (pins 6) of SCA6X0. The self test Input high voltage level is 4 – Vdd+0.3 V and input low voltage level is 0.3 – 1 V. 5V ST pin voltage 0V 5V Vout V1 V2 T1 0V T5 TIME [ MS ] Figure 7. Self test wave forms. V3 T2 T3 T4 V1 = initial output voltage before the self test function is activated. V2 = output voltage during the self test function. V3 = output voltage after the self test function has been de-activated and after stabilization time Please note that the error band specified for V3 is to guarantee that the output is within 5% of the initial value after the specified stabilization time. After a longer time (max. 1 second) V1=V3. T1 = Pulse length for Self test activation T2 = Saturation delay T3 = Recovery time T4 = Stabilization time =T2+T3 T5 = Rise time during self test. T1 [ms] 10-100 T2 [ms] Typ. 20 T3 [ms] Typ. 50 T4 [ms] Typ. 70 T5 [ms] Typ. 10 V2: Min 0.95*VDD (4.75V @Vdd=5V) V3: 0.95*V11.05*V1 Self test characteristics. Murata Electronics Oy www.muratamems.fi Doc. nr. 82 1580 00 9/13 Rev.B SCA610-E28H1A 3. Mechanical Specification Lead frame material: Plating: Solderability: Co-planarity: The part weights: 3.1. Copper Nickel followed by Gold JEDEC standard: JESD22-B102-C 0.1 mm max. ~0.73 g Dimensions Figure 8. Mechanical dimensions [mm]. Murata Electronics Oy www.muratamems.fi Doc. nr. 82 1580 00 10/13 Rev.B SCA610-E28H1A 4. Application information The SCA6X0 should be powered from a well regulated 5 V DC power supply. Coupling of digital noise to the power supply line should be minimized. 100nF filtering capacitor between VDD pin 8 and GND plane must be used. If regulator is placed far from component for example other PCB it is recommend adding more capacitance between VDD and GND to ensure current drive capability of the system. For example 470 pF and 1uF capacitor can be used. The SCA6X0 has a ratiometric output. To get the best performance use the same reference voltage for both the SCA6X0 and Analog/Digital converter. Locate the 100nF power supply filtering capacitor close to VDD pin 8. Use as short a trace length as possible. Connect the other end of capacitor directly to the ground plane. Connect the GND pin 4 to underlying ground plane. Use as wide ground and power supply planes as possible. Avoid narrow power supply or GND connection strips on PCB. 4.1. Recommended PCB la y-out Figure 9. Recommended PCB lay-out [mm]. Notes: • It is important that the part is parallel to the PCB plane and that there is no angular alignment error from intended measuring direction during assembly process. • 1° mounting alignment error will increase the cross-axis sensitivity by 1.7% • 1° mounting alignment error will change the output by 17 mg • Wave soldering is not recommended • Ultrasonic cleaning is not allowed • A supply voltage by-pass capacitor (> 100 nF) is recommended Murata Electronics Oy www.muratamems.fi Doc. nr. 82 1580 00 11/13 Rev.B SCA610-E28H1A 4.2. Reflow soldering The SCA6X0 is suitable for Sn-Pb eutectic and Pb- free soldering process and mounting with normal SMD pick-and-place equipment. Recommended body temperature profile during reflow soldering: Figure 10. Recommended body temperature profile during reflow soldering. Ref. IPC/JEDEC J-STD-020D. Profile feature Average ramp-up rate (TL to TP) Sn-Pb Eutectic Assembly Pb-free Assembly 3 °C/second max. 3 °C/second max. 150 °C Preheat - Temperature min (Tsmin) 100 °C - Temperature max (Tsmax) 150 °C 200 °C - Time (min to max) (ts) 60-120 seconds 60-180 seconds Tsmax to TL - 3°C/second max Ramp up rate Time maintained above: - Temperature (TL) - Time (tL) Peak temperature (TP) Time within 5 °C of actual Peak Temperature (TP) Ramp-down rate Time 25 °C to Peak temperature 183 °C 217 °C 60-150 seconds 60-150 seconds 240 +0/−5 °C 250 +0/−5 °C 10-30 seconds 20-40 seconds 6 °C/second max 6 °C/second max 6 minutes max 8 minutes max The Moisture Sensitivity Level of the part is 3 according to the IPC/JEDEC J-STD-020D. The part should be delivered in a dry pack. The manufacturing floor time (out of bag) in the customer’s end is 168 hours. Murata Electronics Oy www.muratamems.fi Doc. nr. 82 1580 00 12/13 Rev.B SCA610-E28H1A Notes: • Preheating time and temperatures according to guidance from solder paste manufacturer. • It is important that the part is parallel to the PCB plane and that there is no angular alignment error from intended measuring direction during assembly process. • Wave soldering is not recommended. • Ultrasonic cleaning is not allowed. The sensing element may be damaged by an ultrasonic cleaning process The Moisture Sensitivity Level of the part is 3 according to the IPC/JEDEC J-STD020B. The part should be delivered in a dry pack. The manufacturing floor time (out of bag) in the customer’s end is 168 hours. Maximum soldering temperature is 250 °C/40 sec. Rework after the initial soldering process is not recommended. Rework can cause heat build-up to the leg and this heat build-up will cause the housing material to get soft thus allowing the leg to move. The movement can cause bond wire disconnection inside the part. Murata Electronics Oy www.muratamems.fi Doc. nr. 82 1580 00 13/13 Rev.B