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Document overview
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Technical content
Features
Single +5 V supply Current consumption 2.5 mA typical Ratiometric output in relation to supply 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
Applications
SCA630 product family is targeted to automotive applications with high stability and reliability requirements. Typical applications include: Electronic Stab ility Control (ESC) Engine Vibration Measurement Roll Over Suspension Inclination Figure 1. Functional block diagram.
Murata Electronics Oy 2/14 Table of Contents
Murata Electronics Oy 3/14 1. Electrical Specifications 1.1. Absolute Maximum Ratings Parameter Value Units Acceleration (powered or non-powered) 20 000 (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 750 corner pins V Temperature range (storage) −50 to +125 °C Temperature range (operating) −40 to +125 °C 1 Equals to drop from 1 meter on a concrete surface. 1.2. Performance Characteristics VDD = 5.00 V and ambient temperature unless otherwise specified. KPCA) Parameter Condition Min. Typ Max. Units Measuring range Nominal -12.3 +13.3 g Supply voltage Vdd 4.75 5.0 5.25 V <CC> Current consumption Vdd = 5 V; No load 2.5 4.0 mA Operating temperature −40 +125 °C Resistive output load Vout to Vdd or Vss 20 k Ω Capacitive load Vout to Vdd or Vss 20 nF Min. output voltage; Vdd = 5 V 20k from Vout to Vdd 0 0.25 V Max. output voltage; Vdd = 5 V 20k from Vout to Vss 4.75 5.00 V Linear output voltage range Limiter function enabled 0.5 4.5 V <CC> Offset (Output at +1 g) @ room temperature Vdd/2 V <CC> Sensitivity @ room temperature 0.150 (0.03*Vdd) V/g <SC> Offset Error (Output at +1 g) −40 °C...125 °C -870 0 +870 mg <SC> Sensitivity error −40 °C...125 °C −5 0 +5 % Typical non-linearity Within the measuring range −400 +400 mg Amplitude response −3 dB B) 250 400 550 Hz <SC> Cross-axis sensitivity @ room temperature 3.9 % Output noise From DC...4 kHz 5 mV rms Start-up delay Reset and parity check 10 ms Self test pull down resistor (Internal) 44 62 80 k Ω 1. CC= Critical Characteristics. Must be 100% monitored during production SC= Significant Characteristic. The pr ocess capability (Cpk) must be better than 1.33, which allows sample based testing. If process is not capable the part will be 100% tested 2. Output has true DC response
Murata Electronics Oy 4/14 1.3. Offset and sensi tivity calibration Vout offset is calibrated in 0g position: gVOffset out 1 [V] Nominal offset is Vdd/2: dd nom VOffset [V] Sensitivity is calibrated as: g gVgVySensitivit outout 11 [V/g] Nominal sensitivity is: 150.0nomySensitivit [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: ErrorySensitivitErrorOffsetErrorTotal ___ [mg] Offset error is specified as: ySensitivit VgVout ErrorOffset dd [mg] Sensitivity error percent is specified as: nom nom ySensitivit ySensitivitggVoutgVoutErrorySensitivit Sensitivity error is specified as: ySensitivit ErrorySensitivitgVoutVoutErrorySensitivit %_1_ [mg]
Usage of external 100 nF power supply bypass capacitor is recommended. Supply voltage ramp at startup. Figure 2. VDD Start-up sequence.
If self-test (Pin 6) is not used it should be left floating. Pins 1, 2, 3, and 5 are left floating. Figure 3. Electrical connection of SCA630 component.
1 CLK Float / Not connected
2 C1 Float / Not connected
3 MODE Float / Not connected
4 GND Supply Negative supply voltage (V SS) Ground
5 PGM Float / Not connected
6 ST Input Self-test control Float when not used
7 VOUT Output Sensor output vo ltage Measuring circuit input
8 VDD Supply Positive supply voltage (V DD) Vdd (+5V)
The table below defines the limiter function. Figure 4. Limiter function. DD = 5.0 V), when limiter is enabled, the output voltage is valid between 0.5 V…4.5 V.
Murata Electronics Oy 9/14 2. Functional Description 2.1. Measuring directions 2.2. Voltage to accele ration conversion Analog output can be transferred to acceleration using the following equation for conversion: ySensitivit gVVonAccelerati outout 0 [g] where: Vout(0g) = nominal output of the device at 0g po sition 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/D- converter) is used, the error caused by referenc e voltage variation is automatically compensated for. 2.4. Selftest and fa ilure detection modes To ensure reliable measurement results the SCA6 X0 has continuous interconnection failure and calibration memory validity detection. A detected fa ilure forces the output signal close to power supply ground or VDD level, outside the normal output range. The calibration memory validity is verified by co ntinuously running parity check for the control register memory content. In the case where a par ity 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 functi on is activated by a separate on-off command on the self test input. 0 g position Vout,nom = 2.35 V +1 g position Vout,nom = 2.5 V -1 g position Vout,nom = 2.20 V
4 – Vdd+0.3 V and input low voltage level is 0.3 – 1 V. Figure 7. Self test wave forms. V1 = initial output voltage before the self test function is activated. V2 = output voltage during the self test function. initial value after the specified stabilization time. After a longer time (max. 1 second) V1=V3. T5 = Rise time during self test.
Figure 8. Mechanical dimensions [mm].
of the system. For example 470 pF and 1uF capacitor can be used. voltage for both the SCA6X0 and Analog/Digital converter. narrow power supply or GND connection strips on PCB. Figure 9. Recommended PCB lay-out [mm]. error from intended measuring direction during assembly process.
Figure 10. Recommended body temperature profile during reflow soldering. Ref. Average ramp-up rate (TL to TP) 3 °C/second max. 3 °C/second max. customer’s end is 168 hours.
Murata Electronics Oy 14/14 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 par t is 3 according to the IPC/JEDEC J-STD- 020B. The part should be delivered in a dry pack. The manufacturing floor time (out of bag) in the customer’s end is 168 hour s. 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.