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Datasheet File OCR Text: |
this is information on a product in full production. october 2013 docid18315 rev 6 1/65 stm8t143 single-channel capacitive sensor for touch and proximity detection datasheet - production data features ? touch and short range proximity detection ? internal samp ling capacitor ? on-chip integrated voltage regulator ? automatic electrode tuning (aet) ? electrode parasitic capa citance compensation (epcc) ? dynamic calibration (dycal?) ? environment control system (ecs) ? user programmable options include: ? configurable output modes ? configurable sensitivity levels ? data streaming mode ? low power management ? operating supply voltage: 3 v to 5.5 v ? supported interface: ? individual key state output ? single wire data interface ? operating temperature: -40 to +85 c ? ecopack? 8-pin so and 8-pin ufdfpn packages applications ? ear-face proximity detection for smart phone devices ? companion device for navigation joystick/optical track pad ? user hand detection for nomad equipment (tablet pc) ? ear-head detection for mp3/walkman ear buds and bluetooth headsets ? on/off touch sensing button such as gps system home button ? user hands detection for mouse/keyboards ? wall switch backlight activation on user approach and light controls on user touch ufdfpn8 (2 x 3 mm) so8 (narrow) www.st.com
contents stm8t143 2/65 docid18315 rev 6 contents 1 description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2 block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3 pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4 stm8t proxsense technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.1 capacitive sensing overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 4.2 charge-transfer acquisition principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 4.3 internal sampling capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 4.4 electrode parasitic capacitance compensation (epcc) . . . . . . . . . . . . . . 13 5 stm8t143 processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.1 automatic electrode tuning (aet) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.2 signal calculation and reference calibration . . . . . . . . . . . . . . . . . . . . . . . 15 5.3 detection and release thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 5.4 dynamic calibration (dycal) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5.5 environment control system (ecs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 5.5.1 ecs principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 5.5.2 ecs halt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 5.5.3 reference freeze and reference freeze ti meout . . . . . . . . . . . . . . . . . . 23 5.5.4 ecs filter constant adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 5.6 debounce filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 6 device operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 6.1 option byte description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 6.2 device operating modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 6.2.1 dual output mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 6.2.2 control mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 6.2.3 data streaming mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 6.3 output polarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 6.4 power modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 docid18315 rev 6 3/65 stm8t143 contents 4 7 typical application diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 8 design guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 8.1 sensitivity adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 8.1.1 pcb layout and construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 9 electrical characteristi cs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 9.1 parameter conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 9.1.1 minimum and maximum values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 9.1.2 typical values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 9.1.3 typical curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 9.1.4 loading capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 9.2 absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 9.3 operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 9.3.1 general operating conditions and supply characteristics . . . . . . . . . . . 38 9.3.2 average current consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 9.3.3 i/o pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 9.4 regulator and reference voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 9.5 capacitive sensing characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 9.6 streaming mode characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 9.7 emc characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 9.7.1 functional ems (electromag netic susceptibility) . . . . . . . . . . . . . . . . . . 45 9.7.2 prequalification trials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 9.7.3 electromagnetic interference (emi) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 9.7.4 absolute maximum ratings (electrical sensit ivity) . . . . . . . . . . . . . . . . . 46 9.7.5 electrostatic discharge (esd) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 9.7.6 static latchup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 10 package characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 10.1 package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 10.1.1 so8 package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 10.1.2 ufdfpn8 package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 10.2 package thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 10.2.1 reference document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 11 ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 contents stm8t143 4/65 docid18315 rev 6 11.1 stm8t143 ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . 53 11.2 orderable favorite device lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 11.2.1 part number option bytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 11.3 in-factory option byte programming service . . . . . . . . . . . . . . . . . . . . . . . 54 11.4 revision code on device markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 12 stm8t143 programming tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 13 revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 docid18315 rev 6 5/65 stm8t143 list of tables 5 list of tables table 1. stm8t143 pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 table 2. option bytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 table 3. option byte description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 table 4. pin 1 configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 table 5. pin 8 configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 table 6. data streaming frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 table 7. voltage characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 table 8. current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 table 9. thermal characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 table 10. operating characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 table 11. average current consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 table 12. out/tout/data streaming pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 table 13. pout/tout pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 table 14. ctrl pin characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 table 15. regulator and reference voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 table 16. general capacitive sensing characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 table 17. internal c s value. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 table 18. implemented epcc values (pf) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 table 19. external sensing component characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 table 20. data streaming timing characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 table 21. ems data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 table 22. emi data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 table 23. esd absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 table 24. electrical sensitivities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 table 25. so8-lead plastic small outline - package mechanical data. . . . . . . . . . . . . . . . . . . . . . . . . 48 table 26. ufdfpn8-lead ultra thin fine pitch dual flat - package mechanical data . . . . . . . . . . . . . . 50 table 27. thermal characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 table 28. option byte values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 table 29. device identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 table 30. ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 table 31. document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 list of figures stm8t143 6/65 docid18315 rev 6 list of figures figure 1. stm8t143 block diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 figure 2. so8 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 figure 3. ufdfpn8 pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 figure 4. coupling with hand increases the capacitance of the sensing electrode . . . . . . . . . . . . . . 11 figure 5. stm8t143 measuring circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 figure 6. signal monitored on c x pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 figure 7. automatic electrode tuning (aet) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 figure 8. signal reference and detection threshold (not detailed) . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 figure 9. dycal general operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 figure 10. dycal operation with water resi due . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 figure 11. no dycal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 figure 12. iir filter formula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 figure 13. ecs halt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 figure 14. unwanted detection managed by the reference fr eeze timeout . . . . . . . . . . . . . . . . . . . . . 23 figure 15. ecs filter k constant managemen t. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 figure 16. data streaming frame . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 figure 17. typical application schematic for control mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 figure 18. typical application schematic for dual output mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 figure 19. typical application schematic for data streaming mode. . . . . . . . . . . . . . . . . . . . . . . . . . . 35 figure 20. pin loading conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 figure 21. data streaming timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 figure 22. so8-lead plastic small outline - package outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 figure 23. so8 narrow recommended footprint (dimensions in mm) . . . . . . . . . . . . . . . . . . . . . . . . . 49 figure 24. ufdfpn8-lead ultra thin fi ne pitch dual flat package (mlp) package outline . . . . . . . . . . 50 figure 25. ufdfpn 2 x 3 mm recommended footprint (dimen sions in mm) . . . . . . . . . . . . . . . . . . . . 51 figure 26. stm8t143 ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 figure 27. so8 package ma rking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 figure 28. ufdfpn8 package marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 figure 29. stm8t143 programming tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 docid18315 rev 6 7/65 stm8t143 description 64 1 description the stm8t143 is a single channel, fully integrated, touch sensing capacitive sensor. it uses a proxsense? charge transfer capacitive acquisi tion method that is capable of near range proximity detection. the stm8t143 offers a state of the art capacitive sensing engine with an embedded sampling capacitor and voltage regulator allowing the overall solution cost to be reduced and improving system immunity in noisy environments. it can target a detection range up to 20 cm thanks to the electrode parasitic capacitance compensation (epcc) feature. the epcc automatically compensates ground parasitic capacitance sources (such as ground planes, printed circuit board tacks, and large metal objects) which significantly reduce the proximity detection range. the application fields or typical functions wit h proximity features are various and include: on/off switches, replacement/enhancement, home buttons, backlighting feature on proximity for user interfaces, wakeup or control function on proximity, find-in-the-dark for lighting equipment, and companion device for battery saving in portable equipment. the device has been designed to be used in applications where proximity is required and touch conditions can prevail for an extended period of time which may result in uncompensated drift in conventional capaci tive sensors. theref ore, a process called dycal is implemented. the stm8t143 is an ideal alternative, cost-effective, and extremely low power solution to replace conventional infrared optical proximity sensors. capacitive sensing technology is not sensitive to sunlight or artificial light effects. the stm8t143 offers a much lower consumption (12 a range versus 100 a range) and a small form factor (dfn8 2*3*0.65 mm). lastly, there is no need for a clear opening on the bezel to let light pass through. the stm8t143 is offered in 8-pin packages and features both touch and proximity sensing outputs. the stm8t143 touch pad can sense through almost any dielectric and thereby allows the electronics to be contained in a sealed enclosure. note: proxsense? is a trademark of azoteq (pty) ltd. block diagram stm8t143 8/65 docid18315 rev 6 2 block diagram figure 1. stm8t143 block diagram rc oscillator the 1-mhz rc oscillator is an internal fixed fr equency oscillator used to supply the clock to the mcu system engine. voltage regulator the voltage regulator has an internal comparison and feedback circuit that ensures the v reg voltage is kept stable and constant. the regulator requires an external smoothing capacitor. mcu system engine the mcu system engine controls the capacitive sensing engine and processes touch and proximity detection signals. advanced proxsense engine the advanced proxsense engine circuitry uses a charge-transfer method to detect capacitance changes. it features: ? an analog voltage comparator ? a programmable internal sampling capacitor ? a system that allows the grou nd parasitic capacitance to be compensated to improve the system sensitivity. this system is called electrode parasitic capacitance compensation (epcc). d l f & |