PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications KXR94-2353 Rev. 3 Nov-2010 Product Description The KXR94-2353 is a Tri-axis, silicon micromachined accelerometer with a full-scale output range of +/-2g (19.6 m/s/s). The sense element is fabricated using Kionix’s proprietary plasma micromachining process technology. Acceleration sensing is based on the principle of a differential capacitance arising from acceleration-induced motion of the sense element, which further utilizes common mode cancellation to decrease errors from process variation, temperature, and environmental stress. The sense element is hermetically sealed at the wafer level by bonding a second silicon lid wafer to the device using a glass frit. A separate ASIC device packaged with the sense element provides signal conditioning and self-test. The accelerometer is delivered in a 5 x 5 x 1.2 mm DFN plastic package operating from a 2.5 – 5.25V DC supply. There are 4 factory programmable modes of operation for the KXR94: Mode 00 – The three outputs (X, Y, Z) are read through the digital SPI interface, which is also used to command Selftest and Standby Mode. The digital I/O pads are powered from a separate power pin, and will interface to 1.8V logic. Mode 01 – The three outputs (X, Y, Z) are provided on three analog output pins. The KXR94 also features an integrated 3-channel multiplexer (X, Y, Z). The Enable pin must be high for normal operation and low for power shutdown. Mode 10 – The three outputs (X, Y, Z) are provided on three analog output pins. The KXR94 also features an integrated 4-channel multiplexer (X, Y, Z, Aux In). The Enable pin must be high for normal operation and low for power shutdown. Mode 11 – The three outputs (X, Y, Z) are provided on three analog output pins. The KXR94 also features an integrated 4-channel multiplexer (X, Y, Z, Aux In). The Enable pin must be low for normal operation and high for power shutdown. The KXR94-2353 is factory programmed to be in MODE 00. 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 1 of 15 PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications KXR94-2353 Rev. 3 Nov-2010 Functional Diagram X Sensor Charge Amplifier 32K Temp Sensor Y Sensor Z Sensor Vdd 8 Charge Amplifier 2 Output X C2 32K 1kHz LPF Output Y 13 C3 Charge Amplifier 32K Output Z 14 C4 Oscillator A/D 4 Aux In GND 12 SPI GND 3 5 6 7 9 10 IO Vdd SDO SCLK Enable SDI 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 2 of 15 PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications KXR94-2353 Rev. 3 Nov-2010 Product Specifications Table 1. Mechanical (specifications are for operation at 3.3V and T = 25C unless stated otherwise) Parameters Units Operating Temperature Range ! Zero-g Offset Zero-g Offset Variation from RT over Temp. Typical -40 - 85 counts 1918 2048 2178 803 819 mg/ºC ! Sensitivity Min ºC counts/g 0.2 %/ºC 0.01 (xy) 0.02 (z) Offset Ratiometric Error (Vdd = 3.3V ± 5%) mg 4 Sensitivity Ratiometric Error (Vdd = 3.3V ± 5%) % 1.25 (xy) 0.2 (z) % of FS 0.1 Sensitivity Variation from RT over Temp. Non-Linearity Cross Axis Sensitivity 1 Self Test Output change on Activation Bandwidth (-3dB) Max % 2 g 1.9 (xy) 0.5 (z) 835 2 Hz 800 Noise Density (on filter pins) g / √Hz 45 ! Denotes Special Characteristics: These characteristics have been identified as important to the customer. Notes: 1. 2. Cross axis sensitivity is dominated by the placement accuracy of the component during PCB assembly and in the application. Bandwidth for internal low pass filter only. Lower frequencies are user definable with external capacitors. (See Application Design Equations) 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 3 of 15 PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications KXR94-2353 Rev. 3 Nov-2010 Table 2. Electrical (specifications are for operation at 3.3V and T = 25C unless stated otherwise) Units Min Typical Max Supply Voltage (Vdd) Operating Parameters V I/O Pads Supply Voltage (VIO) V 2.5 1.7 3.3 - 5.25 Vdd A 500 950 1400 60 40 5 0.2 * VIO - Current Consumption Operating ! Standby A V V A s MHz Input Low Voltage Input High Voltage Input Pull-down Current A/D Conversion time SPI Communication Rate 0.8 * VIO 5 Analog Output Resistance(Rout) 24 32 40 k ! Denotes Special Characteristics: These characteristics have been identified as important to the customer. Table 3. Environmental Units Min Target Max Supply Voltage (Vdd) Absolute Limits Maximum Operating Temperature Range Storage Temperature Range Mech. Shock (powered and unpowered) Parameters V ºC ºC g -0.3 -40 -55 - - 7.0 125 150 5000 for 0.5ms ESD V - - 3000 HBM Caution: ESD Sensitive and Mechanical Shock Sensitive Component, improper handling can cause permanent damage to the device. This product conforms to Directive 2002/95/EC of the European Parliament and of the Council of the European Union (RoHS). Specifically, this product does not contain lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB), or polybrominated diphenyl ethers (PBDE) above the maximum concentration values (MCV) by weight in any of its homogenous materials. Homogenous materials are "of uniform composition throughout." 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 4 of 15 PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications HF KXR94-2353 Rev. 3 Nov-2010 This product is halogen-free per IEC 61249-2-21. Specifically, the materials used in this product contain a maximum total halogen content of 1500 ppm with less than 900-ppm bromine and less than 900-ppm chlorine. Soldering Soldering recommendations available upon request or from www.kionix.com. 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 5 of 15 PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications KXR94-2353 Rev. 3 Nov-2010 Application Schematic X C2 Aux In IO Vdd SDO SCLK 1 14 2 13 3 12 4 KXR94 11 5 10 6 9 7 8 Z C3 Y C4 SDI nCS Vdd C1 Table 4. KXR94 Pad Descriptions Pad Name 1 NC 2 X output 3 4 5 6 7 8 9 10 11 12 GND Aux In IO Vdd SDO SCLK Vdd nCS SDI NC GND 13 Y Output 14 Z Output Center pad Description Not Connected Internally (can be connected to Vdd or Gnd) Analog output of the x-channel. Optionally, a capacitor (C2) placed between this pin and ground will form a low pass filter. Ground Auxiliary input for analog-digital converter Power Supply for I/O pads SPI Serial Data Output SPI Communication Clock The power supply input. Decouple this pin to ground with a 0.1uF ceramic capacitor (C 1). SPI Chip Select SPI Serial Data Input Not Connected Internally (can be connected to Vdd or Gnd) Ground Analog output of y-channel. Optionally, a capacitor (C3)placed between this pin and ground will form a low pass filter. Analog output of z-channel. Optionally, a capacitor (C4) placed between this pin and ground will form a low pass filter. Ground 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 6 of 15 PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications KXR94-2353 Rev. 3 Nov-2010 Application Design Equations The bandwidth is determined by the internal 1kHz low pass filter. The user can lower the bandwidth by placing filter capacitors connected from pins 2, 13 and 14 to ground. The response is single pole. Given a desired bandwidth, fBW, the filter capacitors are determined by: C2 C3 C4 4.97 x10 f BW 6 KXR94 Digital Interface The Kionix KXR94 digital accelerometer has the ability to communicate on a SPI digital serial interface bus. This flexibility allows for easy system integration by eliminating analog-to-digital converter requirements and by providing direct communication with system micro-controllers. The serial interface terms and descriptions as indicated in Table 6 below will be observed throughout this document. Table 5. Serial Interface Terminologies Term Transmitter Receiver Master Slave Description The device that transmits data to the bus. The device that receives data from the bus. The device that initiates a transfer, generates clock signals and terminates a transfer. The device addressed by the Master. SPI Interface The KXR94 utilizes an integrated Serial Peripheral Interface (SPI) for digital communication. The SPI interface is primarily used for synchronous serial communication between one Master device and one or more Slave devices. The Master, typically a micro controller, provides the SPI clock signal (SCLK) and determines the state of Chip Select (nCS). The KXR94 always operates as a Slave device during standard Master-Slave SPI operation. SPI is a 4-wire synchronous serial interface that uses two control and two data lines. With respect to the Master, the Serial Clock output (SCLK), the Data Output (MOSI) and the Data Input (MISO) are shared among the Slave devices. The Master generates an independent Chip Select (nCS) for each Slave device that goes low at the start of transmission and goes back high at the end. The Slave Data Output (SDO) line, remains in a high-impedance (hi-z) state when the device is not selected, so it does not interfere with any active devices. This allows multiple Slave devices to share a master SPI port as shown in Figure 1 below. 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 7 of 15 PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications Master KXR94-2353 Rev. 3 Nov-2010 Slave Serial Clock CS0 CS1 SCLK CS KXR94 MCU SDI MOSI (Data Out) SDO Slave SCLK CS MISO (Data In) KXR94 SDI SDO Figure 1 KXR94 SPI Connections Control Register Write and Read The control register embedded in the KXR94 has an 8-bit address. Upon power up, the Master must write to the accelerometer’s control register to set its operational mode. On the falling edge of nCS,, a 2-byte command is written to the control register. The first byte, 0x04, initiates the write to the appropriate register, and is followed by the user-defined, operational-mode byte. All commands are sent MSB (most significant bit) first, and the host must return nCS high for at least 200nS before the next data request. Figure 2 below shows the timing diagram for carrying out the 8-bit control register write operation. CLK SDI 0 (MSB) SDO HI-Z 0 0 0 0 1 0 0 D7 D6 D5 D4 D3 D2 D1 D0 (MSB) HI-Z CS Figure 2 Timing Diagram for 8-Bit Control Register Write Operation 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 8 of 15 PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications KXR94-2353 Rev. 3 Nov-2010 In order to read the 8-bit control register, an 8-bit read command, 0x03, must be written to the accelerometer to initiate the read. Upon receiving the command, the accelerometer returns the 8-bit operational-mode data stored in the control register. This operation also occurs over 16 clock cycles. All returned data is sent MSB first, and the host must return nCS high for at least 200nS before the next data request. Figure 3 shows the timing diagram for an 8-bit control register read operation. CLK SDI 0 0 0 0 0 0 1 1 (MSB) SDO HI-Z D7 D6 D5 D4 D3 D2 D1 D0 HI-Z (MSB) CS Figure 3 Timing Diagram for 8-Bit Control Register Read Operation Accelerometer Read Back Operation The KXR94 has an onboard 12-bit ADC that can sample, convert and read back sensor data at any time. Transmission of an 8-bit axis-conversion command (see Table 8) begins on the falling edge of nCS. After the eight clock cycles used to send the command, the host must wait for at least 40µs during the A/D conversion time. Note that all returned data is sent MSB first. Once the data is received, nCS must be returned high for 200nS before the next data request. Figure 4 and 5 this and on the following page show the timing and register diagrams for the accelerometer 12-bit ADC read operation. The Read Back Operation is a 3-byte SPI command. The first byte of SDI contains the command to convert one of the axes. The second and third bytes of SDO contain the 12 bits of the A/D result plus four bits of padding in the LSB to make a total of 16 bits. See Figure 5 on next page. Conversion CLK SDI A7 A6 A5 A4 A3 A2 A1 A0 (MSB) SDO CS HI Z D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 HI Z (MSB) Figure 4 Timing Diagram for an A/D conversion and 12-Bit data read operation. 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 9 of 15 PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications KXR94-2353 Rev. 3 Nov-2010 Axis Conversion Command SDI SDO A7 A6 A5 A4 A3 A2 A1 A0 MSB X X X X X X X X X X X X X X X X MSB D11 D10 D9 D8 D7 D6 D5 D4 X X X X X X X X D3 D2 D1 D0 X X X X Conversion Read Back Data X = Don’t Care Bits Figure 5 Register Diagram for 12-Bit ADC Read Operation SPI Commands The accelerometer SPI interface uses an 8-bit command register to carry out all of its functions. The commands are given in Table 7. Description Convert X axis Convert Y axis Convert Z axis Read Control Register Write Control Register Convert Aux In 1st byte (SDI) (Command) 0x00 0x01 0x02 0x03 0x04 0x07 Table 6 Command Register Bit Utilization Convert X axis (0x00 or 0000 0000) samples the X-axis sensor data held on the filter cap, digitizes it and returns it as 12-bits through SDO. Convert Y axis (0x01 or 0000 0001) samples the Y-axis sensor data held on the filter cap, digitizes it and returns it as 12-bits through SDO. Convert Z axis (0x02 or 0000 0010) samples the Z-axis sensor data held on the filter cap, digitizes it and returns it as 12-bits through SDO. Read Control Register (0x03 or 0000 0011) reads back the current contents of the control register and returns it as 8-bits through SDO. Write Control Register (0x04 or 0000 0100) is used to initiate a write to the control register and set the operational mode of the accelerometer. The first byte initiates the write to the register, and the second byte specifies the operational mode. 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 10 of 15 PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications KXR94-2353 Rev. 3 Nov-2010 Convert Aux In (0x07 or 0000 0111) samples the auxiliary input data, digitizes it and returns it as 12-bits through SDO. Accelerometer Operational Modes The 8-bit read/write control register selects the various operational modes of the accelerometer. Table 8 shows the bit assignments for the available modes. D7 D6 D5 D4 D3 D2 D1 D0 0 0 0 0 0 Enable Self test Parity Table 7 Read/Write Control Register Parity reports on even (0) or odd (1) EEPROM parity. A properly functioning part will return even (0) EEPROM parity. This bit is read-only and operates independently of the other modes. Enable powers up the accelerometer for operation. Enable = 1 – normal operation Enable = 0 – low-power standby Self test activates the self-test function for the sensor elements on all three axes. A correctly functioning part will increase all channel outputs by approximately 1g when Self test = 1 and Enable = 1. This bit can be read or written. Digital Accelerometer SPI Sequence An example of a SPI sequence for reading sensor data is as follows: 1. Power up KXR94 2. nCS low to select 3. Write operational mode command to 8-bit control register – for example: 0x0404. The first 0x04 is the command to write to the control register, the second 0x04 sets the enable bit in the internal register. 4. nCS high for at least 200nS (SCLK = 5MHz) 5. nCS low to select 6. Send convert axis command – for example: 0x000000. The first 0x00 is the command to convert the X-channel. The second and third 0x00 are placeholders. There should be a minimum of 40μs between the first and second bytes in order to give the A/D conversion adequate time to complete. 7. The 12-bit A/D data is read in on the second and third SDO bytes. 8. nCS high for at least 200nS (SCLK = 5MHz) 9. Repeat data read cycle. Recommend reading X-axis, Y-axis, Z-axis, and the Control Register for each read cycle to verify the Control Register mode selection. 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 11 of 15 PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications KXR94-2353 Rev. 3 Nov-2010 Test Specifications ! Special Characteristics: These characteristics have been identified as being critical to the customer. Every part is tested to verify its conformance to specification prior to shipment. Table 8. Test Specifications Parameter Specification Test Conditions 2048 +/- 130 counts 25C, Vdd = 3.3 V Zero-g Offset @ RT 819 +/- 16 counts/g 25C, Vdd = 3.3 V Sensitivity @ RT Current Consumption -- Operating 500 <= Idd <= 1400 uA 25C, Vdd = 3.3 V 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 12 of 15 PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications KXR94-2353 Rev. 3 Nov-2010 Package Dimensions and Orientation 5 x 5 x 1.2 mm DFN +Y +X +Z +Z +X Dimension A B C D E F G H Min 1.10 0.18 0.35 3.50 4.20 mm Nom 5.00 5.00 1.20 0.23 0.50 0.40 3.60 4.30 Max Min 1.30 0.28 0.043 0.007 0.45 3.70 4.40 0.014 0.138 0.165 inch Nom 0.197 0.197 0.047 0.009 0.020 0.016 0.142 0.169 All dimensions and tolerances conform to ASME Y14.5M-1994 When device is accelerated in +X, +Y or +Z direction, the corresponding output will increase. 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 13 of 15 Max 0.051 0.011 0.018 0.146 0.173 PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications KXR94-2353 Rev. 3 Nov-2010 Static X/Y/Z Output Response versus Orientation to Earth’s surface (1g): Position Diagram 1 2 3 4 5 Top 6 Bottom Bottom Top X 2048 counts 2867 counts 2048 counts 1229 counts 2048 counts 2048 counts Y 2867 counts 2048 counts 1229 counts 2048 counts 2048 counts 2048 counts Z 2048 counts 2048 counts 2048 counts 2048 counts 2867 counts 1229 counts X-Polarity Y-Polarity Z-Polarity 0 + 0 + 0 0 0 0 0 0 0 0 + 0 0 - (1g) Earth’s Surface 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 14 of 15 PART NUMBER: ± 2g Tri-axis Digital Accelerometer Specifications KXR94-2353 Rev. 3 Nov-2010 Revision History REVISION 1 2 3 DESCRIPTION Initial Release Added Special Characteristics designation to property tables. Adjusted current specification to six sigma tolerances. Changed to new format, widened Zero-g Offset tolerance to 130 counts, updated SPI rate to 5MHz max, corrected Bandwidth footnote. DATE 06-Aug2007 15-Nov2009 03-Nov2010 "Kionix" is a registered trademark of Kionix, Inc. Products described herein are protected by patents issued or pending. No license is granted by implication or otherwise under any patent or other rights of Kionix. The information contained herein is believed to be accurate and reliable but is not guaranteed. Kionix does not assume responsibility for its use or distribution. Kionix also reserves the right to change product specifications or discontinue this product at any time without prior notice. This publication supersedes and replaces all information previously supplied. 36 Thornwood Dr. – Ithaca, NY 14850 tel: 607-257-1080 – fax:607-257-1146 www.kionix.com - [email protected] © 2010 Kionix – All Rights Reserved 352-1783-1011041430 Page 15 of 15