QST104 STMicroelectronics, QST104 Datasheet
QST104
Related parts for QST104
QST104 Summary of contents
Page 1
... Increased product lifetime February 2008 Capacitive touch sensor device 2 C interface Description The QST104 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 ...
Page 2
... Adjacent key suppression (AKS™ Device operating modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.1 Reset and power- 4.2 Burst operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.3 Low power mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.4 Mode selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 4.5 Stand-alone mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 4.5.1 Main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 4.5.2 KOUT outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 4.5.3 Option descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4.6 I2C mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.6.1 Main features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.6.2 General-purpose outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.6.3 IRQ pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.6.4 Communication packet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.6.5 I2C address selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4.7 Supported commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2/45 www.DataSheet4U.com QST104 ...
Page 3
... QST104 5 Design guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.1 C sense capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 S 5.2 Sensitivity tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.2.1 Increasing sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.2.2 Decreasing sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.2.3 Key balance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.3 Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.4 ESD protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.5 Crosstalk precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.6 PCB layout and construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 6 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 6.1 Parameter conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 6.1.1 Minimum and maximum values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 6.1.2 Typical values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 6.1.3 Typical curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 6.1.4 Loading capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 6.1.5 Pin input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 6 ...
Page 4
... Device overview 1 Device overview The QST104 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 ...
Page 5
... TOD (3) 4 I2C_SDA (HS) TOD (3) 5 I2C_SCL (HS IRQ/OPT6 (HS I2C_SDA (HS) 4 QST104KT6 1) I2C_SCL (HS) 5 RESET DD_1 (1) Stand-alone mode function Key 4 output / BCD output 4 and MOD_0 option resistor OM_0 option resistor www.DataSheet4U.com ...
Page 6
... PP General-purpose output 12 PP General-purpose output 13 Key 1 output / BCD output 1 and MODE option resistor Key 2 output / BCD output 2 and AKS option resistor Key 3 output / BCD output 3 and LP option resistor www.DataSheet4U.com QST104 mode function If unused 10nF capacitor to ground Open Open Open Open ...
Page 7
... QST104 3 QST touch sensing technology 3.1 Functional description QST devices employ bursts of charge-transfer cycles to acquire signals. Burst mode permits low power operation, dramatically reduces RF emissions, lowers susceptibility to RF fields, and yet permits excellent speed. Signals are processed using algorithms pioneered by Quantum which are specifically designed to provide reliable, trouble-free operation over the life of the product ...
Page 8
... As a result, the calibration time of the system can be simply calculated using the following formula: t burst period is described in application note AN2547. For a maximum calibration duration (t ), please refer to CAL 8/45 33 Burst_Period. The methodology used to measure the CAL Section 6.5: Capacitive sensing characteristics on page www.DataSheet4U.com QST104 ) fitted is assumed inSection 6.5: Capacitive 33. 33. ...
Page 9
... QST104 3.7 Fast positive recalibration The device autorecalibrates a key when its signal reflects a decrease in capacitance higher than a fixed threshold (PosRecalTh) for a defined number of acquisitions (PoseRecalI). 3.8 Forced key recalibration A recalibration of the device may be issued at any time by sending to the QST device the 2 appropriate I C command or by tying the RESET pin to ground. ...
Page 10
... 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 QST104 supports two AKS modes: ● Locking AKS Once a key is considered as “ ...
Page 11
... QST104 4 Device operating modes 4.1 Reset and power-up At power-up, the device configures itself according to the pull-up or pull-down option resistors present on pins OPT1 to OPT6. The device start-up and configuration may take Setup When the power is established possible to force a new device configuration by applying a negative pulse on the RESET pin ...
Page 12
... 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 QST104 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 ...
Page 13
... QST104 Figure 3. Stand-alone mode typical schematic 2.4~5.5V V UNREG Volt. Reg. 4.7µF Keep these parts close Key4 10kΩ Key3 10kΩ Key2 10kΩ Key1 10kΩ C 4.5.2 KOUT outputs KOUTn outputs directly reflect the state of keys. These pins are push-pull outputs. Under RESET, these pins are floating and their state depends on the option resistors. Pins KOUTn are active high meaning that when a key is “ ...
Page 14
... Device operating modes 4.5.3 Option descriptions Adjacent key suppression (AKS™) The QST104 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 4. In BCD output mode, the AKS function is always enabled, regardless of the option resistor configuration ...
Page 15
... QST104 Output mode option The QST104 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. ...
Page 16
... Device operating modes 2 4 mode 2 The I C mode offers the largest configurability and functionality of the QST104. 4.6.1 Main features ● 13 general-purpose outputs ● Configuration AKS groups ● Additional low power modes ● Accessible internal capacitive sensing parameters ● Continuous range of Max On-Duration 16/45 www ...
Page 17
... QST104 2 Figure mode typical schematic 2.4~5.5V V UNREG Volt. Reg. 4.7µF Keep these parts close Key4 10kΩ Key3 10kΩ Key2 10kΩ Key1 10kΩ 4.6.2 General-purpose outputs mode allows to drive general-purpose outputs. These output pins are configured in output push pull mode 0 by default ...
Page 18
... I C frames. The first frame is sent by the Master device using the QST104 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 QST104 device address with the write bit reset ...
Page 19
... QST104 2 4.6 address selection The QST104 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 ...
Page 20
... GPOState1 Write GPOState2 Checksum Read ErrCode 20/45 Description Returns the QST104 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: 0x04 single-channel keys NbMCkey: 0x00 multi-channel keys ASCII-coded device name Returns the error information on each key ...
Page 21
... QST104 Table 10. Supported commands (continued commands SET_KEY_ACTIVATION (see Note 4) 0x97 KeyActivation Write Checksum Read ErrCode SET_KEY_GROUP 0x00 0x09 AKSGrpMode Key1Grp Write Key2Grp ...Key8Grp CheckSum Read ErrCode SET_LOW_POWER_MODE 0x92 LowPowerMode Write Checksum Read ErrCode SET_MAX_ON_DURATION 0x8A MaxOnDuration Write Checksum Read ErrCode ...
Page 22
... Key n state When set to ‘1’, the corresponding key is touched. 22/45 C error codes. Description Bit 5 Bit 4 Bit Bit 5 Bit 4 Bit Key 4 State Key 3 State Key 2 State Key 1 State www.DataSheet4U.com QST104 Bit 2 Bit 1 Bit 0 Key error codes Bit 2 Bit 1 Bit 0 ...
Page 23
... QST104 Key activation description Table 14. KeyActivation Bit 7 Bit 6 Key 0 Activation Key activation (Bit 7) 0: Key enabled 1: Key disabled Key identifier (Bits 3:0) 0000: All keys 0001: Key 1 0010: Key 2 Low power mode description Table 15. SetLowPower Bit 7 Bit 6 Free Run 0 in Detect Free Run in Detect (Bit 6) 0: Low Power mode is always enabled, whatever the state of the keys ...
Page 24
... Bit 5 Bit 4 Bit 3 AKSGrp6 AKSGrp5 AKSGrp4 Mode Mode Mode Bit 5 Bit 4 Bit 3 Grp6 Grp5 Grp4 www.DataSheet4U.com QST104 Bit 2 Bit 1 Bit 0 GPO 3 GPO 2 GPO 1 state state state GPO 11 GPO 10 GPO 8 state state state Bit 2 Bit 1 Bit 0 AKSGrp3 AKSGrp2 AKSGrp1 ...
Page 25
... QST104 Key debug state description Table 19. KeyDbgState Value 0x01 0x02 0x04 0x08 0x11 0x14 0x24 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) www.DataSheet4U.com Device operating modes ...
Page 26
... These should be in the order of a few picofarads. 26/45 make the corresponding sensing channel more sensitive. S capacitors S capacitors to achieve equilibrium. The R S www.DataSheet4U.com QST104 for that key will compensate S S value and can S S ...
Page 27
... QST104 5.3 Power supply If the power supply fluctuates slowly with temperature, the QST device compensates automatically for these changes with only minor changes in sensitivity. However, if the supply voltage drifts or shifts quickly, the drift compensation mechanism is not able to keep up, causing sensitivity anomalies or false detections. ...
Page 28
... For additional information on PCB layout and construction, please contact your local ST Sales Office for a list of available application notes. 28/45 loading of one key, cross coupling to another key’s trace can X www.DataSheet4U.com QST104 ...
Page 29
... QST104 6 Electrical characteristics 6.1 Parameter conditions Unless otherwise specified, all voltages are referred to V 6.1.1 Minimum and maximum values Unless otherwise specified the minimum and maximum values are guaranteed in the worst conditions of ambient temperature, supply voltage and frequencies by tests in production on 100% of the devices with an ambient temperature at T the selected temperature range) ...
Page 30
... V respected. 30/45 Input pin V IN Ratings Ratings (1)( could damage the device if an unintentional >V while a negative injection is induced www.DataSheet4U.com QST104 Figure 7. Value Unit −65 to +150 °C Maximum value Unit 7.0 −0 +0 2000 500 maximum is respected maximum IN value ...
Page 31
... QST104 Table 22. Current characteristics Symbol I Total current into V VDD I Total current out of V VSS Output current sunk by RESET pin I Output current sunk by output pin IO Output current source by output pin Injected current on RESET pin (2) I INJ(PIN) (3) Injected current output pin ΣI (2) Total injected current (sum of all I/O and control pins) INJ(PIN) 1 ...
Page 32
... The results are based on C Figure 8. IDD Sleep mode current characteristics 32/45 Conditions 2.7nF and C = 12.5pF S X www.DataSheet4U.com QST104 (1) Min. Typ. Max. Unit 1.71 2.17 mA 3.35 158 215 µA 355 75 99 µA 156 1 µA ...
Page 33
... QST104 6.5 Capacitive sensing characteristics Table 25. External sensing components Symbol C Sense capacitor S C Equivalent electrode capacitor X C Equivalent touch capacitor T R Serial resistance S Table 26. Capacitive sensing parameters Symbol t Calibration duration CAL t Setup duration Setup DI Detection integrator DeTh Detection threshold EDI End of detection integrator ...
Page 34
... Conditions (1) (1) (2) ≤ ≤ (2) Between 10% and 90% ( and T DD CPU Parameter Conditions (Figure 17) . VSS .. VDD www.DataSheet4U.com QST104 unless otherwise specified. A Min. Typ. Max. −0 0.3 400 V ± unless otherwise specified. A Min. Max ...
Page 35
... QST104 Figure 9. Typical 2 2 pins OL load DD 1200 -40°C 25°C 1000 85°C 125°C 800 600 400 200 [mA] load Figure 11. Typical pins OL load DD 1600 -40°C 25°C 1400 85° ...
Page 36
... Figure 18. load DD 1800 1600 1400 1200 1000 800 600 400 200 load www.DataSheet4U.com QST104 Typical load Pins load -40°C 25°C 85°C 125°C V [V] ...
Page 37
... QST104 6.7 RESET pin T = -40°C to 125°C, unless otherwise specified. A Table 29. RESET pin characteristics Symbol Parameter V Input low level voltage IL V Input high level voltage IH Schmitt trigger voltage V hys hysteresis Output low level V (2) OL voltage Pull-up equivalent R (3) ON resistor Generated reset pulse ...
Page 38
... C control interface 6.8 Subject to general operating conditions for V 2 The QST104 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). ...
Page 39
... QST104 Figure 20. Typical application with I 4.7kΩ BUS START SDA t t r(SDA) f(SDA) SCL t t h(STA) w(SCKH bus and timing diagram 4.7kΩ 100Ω SDA 100Ω SCL QST device t t su(SDA) h(SDA w(SCKL) r(SCK) f(SCK) www.DataSheet4U.com ...
Page 40
... Package mechanical data 7 Package mechanical data Figure 21. 32-pin low profile quad flat package (7x7) outline Seating plane Pin 1 identification 40/ ccc www.DataSheet4U.com QST104 c 0.25 mm Gage plane 5V_ME ...
Page 41
... QST104 Table 32. 32-pin low profile quad flat package mechanical data Dim. Min 0.050 A2 1.350 b 0.300 c 0.090 D 8.800 D1 6.800 D3 E 8.800 E1 6.800 0.450 L1 K 0.0° ccc 1. Values in inches are converted from mm and rounded to 4 decimal digits. mm Typ. Max. Min. 1.600 ...
Page 42
... ST Sales Office. The category of second Level Interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. 42/45 www.DataSheet4U.com QST QST104 6 ...
Page 43
... 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. GET_PROTOCOL_VERSION returns 0x01 as I2CSpeed byte while it should return 0x00 (maximum speed is 100 kHz). A QST104 B QRG ...
Page 44
... Revision history 10 Revision history Table 35. Document revision history Date Revision 26-Nov-2007 5-Feb-2008 44/45 1 Initial release. 2 Upgraded document status to datasheet. www.DataSheet4U.com QST104 Changes ...
Page 45
... QST104 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. ...