QST108 STMicroelectronics, QST108 Datasheet
QST108
Related parts for QST108
QST108 Summary of contents
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... Increased product lifetime November 2007 Capacitive touch sensor device 2 C interface Description The QST108 is the ideal solution for the design of capacitive touch sensing user interfaces. Touch-sensitive controls are increasingly replacing electromechanical switches in home appliances, consumer and mobile electronics, and in computers and peripherals. Capacitive ...
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... Adjacent key suppression (AKS™ Device operating modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 4.1 Reset and power- 4.2 Burst operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 4.3 Low power mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 4.4 Mode selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 4.5 Stand-alone mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 4.5.1 4.5.2 4.5.3 4.6 I2C mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.6.1 4.6.2 4.6.3 4.6.4 4.6.5 4.7 Supported commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2/47 Main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 KOUT outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Option descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 General-purpose outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 IRQ pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Communication packet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 I2C address selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 QST108 ...
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... QST108 5 Design guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.1 C sense capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 S 5.2 Sensitivity tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.2.1 5.2.2 5.2.3 5.3 Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5.4 ESD protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5.5 Crosstalk precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5.6 PCB layout and construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 6 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 6.1 Parameter conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 6.1.1 6.1.2 6.1.3 6.1.4 6.1.5 6.2 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 6.3 Operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 6.4 Supply current characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 6.5 Capacitive sensing characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 6.6 KOUTn/OPTn/GPOn pin characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 35 6.6.1 6.6.2 6.7 RESET pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 6.8 I2C control interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 7 Package mechanical data ...
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... Contents 10 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 4/47 QST108 ...
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... QST108 1 Device overview The QST108 capacitive touch sensor pure digital solution based on Quantum's patented charge-transfer (QProx™) capacitive technology. This technology allows users to create simple touch panel sensing electrode interfaces for conventional or flexible printed circuit boards (PCB/FPCB). Sensing electrodes are part of the PCB layout (copper pattern or printed conductive ink) and may be used in various shapes (circle, rectangular, etc ...
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... Stand-alone mode function Key 4 output / BCD output 4 and MOD_0 option resistor Key 5 output and MOD_1 option resistor PP/OD Key 6 output and (HS) OM_0 option resistor TOD Key 7 output (HS) TOD Key 8 output (HS) QST108 24 SNS_SCK6 23 SNSK_SCK5 22 SNS_SCK5 21 SNSK_SCK4 20 SNS_SCK4 19 SNSK_SCK3 18 SNS_SCK3 17 SNSK_SCK2 ...
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... QST108 Table 2. Device pin description (continued) Pin Pin name Type 6 RESET DD_1 9 V SS_1 10 V SS_2 11 V SS_3 12 V SS_4 13 V DD_2 14 SNS_SCK1 15 SNSK_SCK1 16 SNS_SCK2 17 SNSK_SCK2 18 SNS_SCK3 19 SNSK_SCK3 20 SNS_SCK4 21 SNSK_SCK4 22 SNS_SCK5 23 SNSK_SCK5 24 SNS_SCK6 25 SNSK_SCK6 26 SNS_SCK7 27 SNSK_SCK7 28 SNS_SCK8 29 SNSK_SCK8 (2) 30 ...
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... C S cause the charge transferred into C X can thus be increased to allow larger values and C , and changes in either can result in substantial X S Sense capacitor C (a few nF) S QST108 , which rise more S reduce the rise tolerated (~5 pF) T Earth C ...
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... QST108 3.3 Faulty and unused keys Any sensing channel that does not have its sense capacitor (C either faulty or unused. This channel takes no further part in operation unless a Master- commanded recalibration operation shows it to have an in-range burst count again. Faulty, unused or disabled keys are still bursted but not processed to avoid modifying the sensitivity of active keys ...
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... In this latter case, the sensor will compensate for the object's removal very quickly, usually in only a few seconds. 10/ command and V do not cause the device and V over time. Depending on the QST108 and DD ...
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... Adjacent key suppression (AKS™ Quantum-patented feature which prevents multiple keys from responding to a single touch. This can happen with closely spaced keys scroll wheel that has buttons very near it. The QST108 supports two AKS modes: ● Locking AKS Once a key is considered as “ ...
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... IRQ pin. In this case, the low power mode is disabled until a command is received from the host. – Inside an I period is skipped. 12/47 . Key touches are acquired using two successive bursts command, between the Write and the Read I QST108 2 C frames, the sleep ...
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... The device operating mode is selected using option pin 1 (OPT1) while the device settings are configured using option pins OPT2 to OPT6 at power-up and after a reset. To fit most applications, the QST108 device offers two different operating modes: ● Stand-alone mode This mode allows the user to simply replace existing mechanical switches with a capacitive sensing solution ...
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... Device operating modes 4.5.1 Main features ● Pins KOUT1 to KOUT8 directly reflect the state of keys ● Selectable global adjacent key suppression (AKS™) ● Selectable sleep duration ● Selectable Max On-Duration values ● Selectable BCD mode 14/47 QST108 ...
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... QST108 Figure 3. Stand-alone mode typical schematic 2.4~5.5V V UNREG Volt. Reg. 4.7µF Keep these parts close Key8 10kΩ Key7 10kΩ Key6 10kΩ Key5 10kΩ Key4 10kΩ Key3 10kΩ Key2 10kΩ ...
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... Device operating modes 4.5.3 Option descriptions Adjacent key suppression (AKS™) The QST108 features an adjacent key suppression (AKS™) function. This function is enabled using the AKS option resistor (OPT2) in standard output mode as described in Table of the option resistor configuration. Table 4. AKS truth table ...
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... QST108 Output mode option The QST108 offers several outputs mode to fit any existing application. Table 7. Output mode (OM) truth table OPT6/OM V Individual key state output mode: One output per sensing channel SS V BCD output mode: Binary-coded touched key number (see BCD mode, the AKS function is always active. ...
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... Device operating modes 2 4 mode 2 The I C mode offers the largest configurability and functionality of the QST108. 4.6.1 Main features ● 5 general-purpose outputs ● Configuration AKS groups ● Additional low power modes ● Accessible internal capacitive sensing parameters ● Continuous range of Max On-Duration 2 Figure 4 ...
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... I C frames. The first frame is sent by the Master device using the QST108 device address with the write bit set. The data bytes consist of the command byte which is eventually followed by the parameters and a checksum byte. The second one is sent by the Master device using the QST108 device address with the write bit reset ...
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... Device operating modes 2 4.6 address selection The QST108 slave address is programmable using the option resistors mapped on pins OPT2 to OPT4 (see Table 9. I²C address versus option resistor Option configuration OPT4 OPT3 ...
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... GPOState Write Checksum Read ErrCode Description Returns the QST108 device version and ASCII-coded device name. This command must be sent first to enable the communication flow. MainVers: Device main version SubVer: Device sub-version NbSCkey: 0x08 single-channel keys NbMCkey: 0x00 multi-channel keys ASCII-coded device name Returns the error information on each key ...
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... ErrCode: Standard Error code (see Sets the Detection, End Of Detection and Positive Recalibration Thresholds for a single key DeTh: Detection Threshold EofDeTh: End of Detection Threshold PosRecalTh: Positive Recalibration Threshold ErrCode: Standard Error code (see for default values. QST108 Table 11) Table 18) Table 11) Table 15) ...
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... QST108 Error codes Table 11 lists the I Table 11. ErrCode ErrCode 0x01 0x83 0x85 0xA1 0xA3 0xE0 KeyError byte description Table 12. KeyError byte description Bit 7 Bit 6 Key State 0 Key state (Bit 7) When set to ‘1’, the corresponding key is touched. This bit is always cleared for the GET_KEY_STATE command ...
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... Low Power mode. The Master device will have to repeat the command to ensure that it is taken in account. 24/47 Bit 5 Bit 4 Bit 0101: Key 5 0110: Key 6 0111: Key 7 1000: Key 8 Bit 5 Bit 4 Bit 3 Sleep Duration Factor 2 C bus activity will wake-up the device. QST108 Bit 2 Bit 1 Bit 0 Key ID (binary coded) Bit 2 Bit 1 Bit frame with ...
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... QST108 GPO state description Table 16. GPOState Bit 7 Bit GPOState Defines the state of the selected general-purpose output pin. For more information, see Section 4.6.2: General-purpose outputs on page 0: GPO state is ‘0’ 1: GPO state is ‘1’ AKS group mode description Table 17. AKSGrpnMode Bit 7 ...
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... Device operating modes Key debug state description Table 19. KeyDbgState Value 0x01 0x02 0x04 0x08 0x11 0x14 0x24 26/47 Description On-going calibration Key released Key touched Key in error Key calibration filter triggered (PosRecalI) Key detection filter triggered (DI) Key end of detection filter triggered (EDI) QST108 ...
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... QST108 5 Design guidelines 5.1 C sense capacitor S The C sense capacitors accumulate the charge from the key electrodes and determine S sensitivity. Higher values of C The values key or to balance unequal sensitivities. Unequal sensitivities can occur due to key size and placement differences and stray wiring capacitances. More stray capacitance on a sense trace will desensitize the corresponding key ...
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... S can result in added ESD and EMC benefits, provided that the S will make crosstalk problems worse; try to keep R S should be placed close to the chip are anticipated (for kOhm or less S QST108 and DD and DD ...
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... QST108 It is important to limit the amount of stray capacitance on the SNS terminals, for example by minimizing trace lengths and widths to allow for higher gain without requiring higher values Under heavy delta-C S cause the other key to trigger. Therefore, electrode traces from adjacent keys should not be ...
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... Loading capacitor The loading conditions used for pin parameter measurement are shown in Figure 6. Pin loading conditions 30/ 25°C and ° 3.3 V (for the 3.0 V ≤ Output pin QST108 = T max (given (for the 4.5V ≤ DD ≤ 3.6 V voltage range). Figure 6. ...
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... QST108 6.1.5 Pin input voltage The input voltage measurement on a pin of the device is described in Figure 7. Pin input voltage 6.2 Absolute maximum ratings Stresses above those listed as “absolute maximum ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device under these conditions is not implied ...
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... DD (1) ground lines (sink lines must always be connected to the external supply. SS >V while a negative injection is induced maximum current injection on four I/O port pins of the device. INJ(PIN) Feature QST108 Maximum value 75 150 20 40 − 25 ± 5 ± 5 ± 20 maximum is respected maximum IN IN value ...
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... QST108 6.4 Supply current characteristics Table 24. Supply current characteristics Symbol Parameter Average suppy current I (FR) DD Free Run mode I DD Average suppy current (Sleep 100ms Sleep mode 100ms Average suppy current (Sleep 500ms Sleep mode 500ms) Average suppy current I Halt DD Halt mode 1 ...
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... Common time step factor DiffFact Differential time step factor BurstCount Burst length 34/47 Parameter Min. Parameter Min. 0 -128 0 -128 0.1 0.1 0.1 0 QST108 Typ. Max. Unit 100 nF 100 kOhm Default Max. Unit TBD ms 100 ms Counts 2 255 Counts -10 -1 Counts ...
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... QST108 6.6 KOUTn/OPTn/GPOn pin characteristics 6.6.1 General characteristics Subject to general operating conditions for V Table 27. General characteristics Symbol V Input low level voltage IL V Input high level voltage IH V Schmitt trigger voltage hysteresis Hys I Input leakage current L C I/O pin capacitance IO t Output high to low level fall time ...
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... V [V] DD Typical load Pins OL DD load -40°C 940 25°C 840 85°C 125°C 740 640 540 440 340 240 140 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4 4.2 4.4 4.6 4.8 5 5.2 5.4 5.6 V [V] DD QST108 = ...
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... QST108 Figure 15. Typical Pins DD OH load DD 800 -40°C 700 25°C 85°C 600 125°C 500 400 300 200 100 [mA] load Figure 17. Typical Pins DD OH load DD 1800 -40° ...
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... I (I/O ports and control pins) must not exceed can be ignored. h(RSTL)in Min. Typ. − 0 +2mA 200 = ( ( 200 Table 22: Current VSS QST108 Max. Unit 0 kΩ μs μ ...
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... C control interface 6.8 Subject to general operating conditions for V 2 The QST108 I C interface meets the requirements of the Standard I protocol described in the following table with the restriction mentioned below: Refer to I/O port characteristics for more details on the input/output alternate function characteristics (SDA and SCL). ...
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... C BUS START SDA t f(SDA) SCL t t h(STA) w(SCKH) 40/ bus and timing diagram 4.7kΩ 100Ω SDA 100Ω SCL t r(SDA su(SDA) h(SDA w(SCKL) r(SCK) f(SCK) QST device REPEATED START t t su(STA) w(STO:STA) STOP t su(STO) QST108 START ...
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... QST108 7 Package mechanical data Figure 21. 32-pin low profile quad flat package (7x7) outline Seating plane Pin 1 identification A1 b ccc Package mechanical data c 0.25 mm Gage plane 5V_ME 41/47 ...
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... Tolerance (mm) 0.10 QST108 (1) inches Min. Typ. Max. 0.0630 0.0020 0.0059 0.0531 0.0551 0.0571 0.0118 0.0146 0.0177 0.0035 0.0079 0.3465 0.3543 0.3622 0.2677 0.2756 ...
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... QST108 8 Part numbering Table 33. Ordering information scheme Example: Device type QST = Capacitive touch sensor Device sub-family 1: QTouch ( QMatrix ( QSlide/QWheel ( 11: QTouch (1.8 to 3.6 V) 15: QMatrix (1.8 to 3.6 V) 16: QSlide/QWheel (1.8 to 3.6 V) Channel count Number of channels Pin count A: 8 pins Y: 16 pins ...
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... As a result, if only one burst is required, the sleep duration during low power mode is doubled. And if two bursts are required, the sleep duration is tripled. 44/47 A QST108 B QRG Marking F00 F01 Section 4.9: Supported commands on page F01 Device revision V 2 command. For 16. QST108 ...
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... QST108 In standalone mode, the 100ms sleep duration low power becomes either a 200ms or 300ms sleep duration depending on the number of bursts required. In I2C mode required to program a sleep duration for one half or a third of the desired sleep duration depending on the number of bursts required. ...
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... Changes Section 2: Pin description on Section 4: 11. Independent output mode 11. chapter from Section 4.4.2: Option 14. 15. 16. 17. 15. 25. 36. 37. Figure 2: QTouch™ measuring circuitry on Section 3.10: Drift compensation on page 13. Table 9: I²C address versus option resistor on and added QST108 7. 18. 31. 32. 11. 33, 33. 39. 44. ...
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... QST108 Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. ...