TS02N 2-Channel Self Calibration Capacitive Touch Sensor SPECIFICATION V1.2 August 2006 ADSemiconductor Confidential ADSemiconductor® TS02N (2-CH Sensitivity Calibration Capacitive Touch Sensor) 1 Specification 1.1 General Feature 2-Channel capacitive touch sensor with self sensitivity calibration Low power consumption Sync function for parallel operation Adjustable internal clock frequency with external resister Open-drain digital output Embedded noise elimination circuit Embedded Internal power reset circuit RoHS compliant 8SOP package 1.2 Application Home appliance Membrane switch replacement Human interface for toys & interactive games Sealed control panels, keypads 1.3 Package (8 SOP) TS02N 8SOP (Drawings not to scale) ADSemiconductor Confidential 1 / 12 ADSemiconductor® TS02N (2-CH Sensitivity Calibration Capacitive Touch Sensor) 2 Pin Description (8 SOP) PIN Number Name I/O 1 SYNC Analog Input 2 3 4 5 6 R_BIAS GND CS1 CS2 VDD Analog Input Ground Analog Input Analog Input Power 7 OUT2 Digital Output 8 OUT1 Digital Output Description Self sense operation signal output Peripheral sense operation signal input Internal bias adjust input Supply ground Sense channel 1 Sense channel 2 Power (2.5V ~ 5.0V) Ch2 touch detect output Open drain output (Active Low) Ch1 touch detect output Open drain output (Active Low) Protection VDD/GND VDD/GND VDD VDD/GND VDD/GND GND VDD/GND VDD/GND 3 Absolute Maximum Rating Supply voltage 5.5 V Maximum voltage on any pin VDD+0.3 V Maximum current on any PAD 100mA Continuous power Dissipation 800mW Storage Temperature -50 ~ 150℃ Operating Temperature -20 ~ 75℃ Junction Temperature 150℃ Note Unless otherwise noted, all above are operated in normal temperature 4 ESD & Latch-up Characteristics 4.1 4.2 ESD Characteristics Mode Polarity H.B.M Pos / Neg M.M Pos / Neg C.D.M Pos / Neg Max 2000V 2000V 2000V 200V 200V 200V 800V Reference VDD VSS P to P VDD VSS P to P DIRECT Max 200mA -200mA 8.0V Test Step Latch-up Characteristics Mode I Test V supply over 5.0V Polarity Positive Negative Positive 25mA 1.0V ADSemiconductor Confidential 2 / 12 ADSemiconductor® TS02N (2-CH Sensitivity Calibration Capacitive Touch Sensor) 5 Electrical Characteristics ▪ VDD=3.3V, RB =510k, (Unless otherwise noted), TA = 25℃ Characteristics Symbol Operating supply voltage VDD Current consumption IDD Output maximum sink current Sense input capacitance range Note1 Sense input resistance range Minimum detectable capacitance difference Min Typ Max Units 2.5 3.3 5.0 V VDD= 3.3V RB=510k - 50 75 VDD= 5.0V RB=510k - 110 165 TA = 25℃ - - 4.0 ㎃ CS1 CS2 - 10 100 ㎊ RS - 200 1000 Ω 0.2 - - ㎊ ΔC > 0.2pF - 12 - ΔC < 0.2pF - 30M - VDD = 3.3V RB = 510k - 100 - VDD = 5.0V RB = 510k - 80 - VDD = 3.3V 200 510 820 VDD = 5.0V 330 620 1200 IOUT ΔC Output impedance (open drain) Zo Self calibration time after power on TCAL Recommended bias resistance range RB Note2 Test Condition ㎂ CS = 10pF Ω ms kΩ Maximum bias capacitance CB_MAX - 820 1000 pF Recommended sync resistance range RSYNC 1 2 20 MΩ Note 1: The sensitivity can be increased with lower CS value. The recommended value of CS is 10pF when using 3T PC(Poly Carbonate) cover and 10 ㎜ x 7 ㎜ touch pattern. Note 2: The lower RB is recommended in noisy condition. ADSemiconductor Confidential 3 / 12 ADSemiconductor® TS02N (2-CH Sensitivity Calibration Capacitive Touch Sensor) 6 Implementation of TS02N 6.1 R_BIAS implementation VDD CB RB R_BIAS << The R_BIAS is connected to the resistor to decide the oscillator and internal bias current. The sensing frequency, internal clock frequency and current consumption are therefore able to be adjusted with RB. A voltage ripple on R_BIAS can make critical internal error, so C B connected to the VDD (not GND) is recommended. (The typical value of CB is 820pF and the maximum Value is 1nF.) I DD. [uA] 200 180 2.5 V 3.3 V 5.0 V 160 140 120 100 80 60 40 20 0 100 200 300 400 500 600 700 800 900 RBIAS [kΩ] Current consumption curve The current consumption curve of TS02N is represented in accordance with RB value as above. The lower RB requires more current consumption but it is recommended in noisy application. For example, refrigerator, air conditioner and so on. ADSemiconductor Confidential 4 / 12 ADSemiconductor® TS02N (2-CH Sensitivity Calibration Capacitive Touch Sensor) 6.2 CS implementation RS2 CS2 << Touch PAD2 CS2 RS1 CS1 << Touch PAD1 CS1 The parallel capacitor CS2 is added to CS2 and CS1 to CS1 to adjust sensitivity. The sensitivity will be increased when smaller value of CS2 and CS1 are used. (Ref. below Sensitivity Example Figure) It could be useful in case detail sensitivity mediation is required. The TS02N has two independent touch sensor input CS1 and CS2. Internal touch decision processes of CS1 and CS2 are separated from each other. Therefore two channel touch key board can be designed by using only one TS02N. RS1 and RS2 are serial connection resistors to avoid mal-function from external surge and ESD. From 200Ω to 1kΩ is recommended for RS1 and RS2 values. The size and shape of PAD might have influence on the sensitivity. The sensitivity will be optimal when the size of PAD is approximately an half of the first knuckle (it’s about 10 ㎜ｘ 7 ㎜). The connection line of CS1 and CS2 to touch PAD is recommended to be routed as short as possible to prevent from abnormal touch detect caused by connection line. Sensitivity Example Figure ADSemiconductor Confidential 5 / 12 ADSemiconductor® TS02N (2-CH Sensitivity Calibration Capacitive Touch Sensor) 6.3 SYNC implementation Over two TS02N can work on the one application at the same time thanks to SYNC function with this pin. The SYNC pulse prevents over two sensing signal from interfering with each other. RSYNC is pull-down resistor of SYNC pin. Too big value of RSYNC makes the SYNC pulse falling delay, and too small value of RSYNC makes rising delay. Typical value of RSYNC is 2MΩ.The Sync pin should be implemented as below. TS02N also can be used with the other TSxx series by employing this SYNC function. The SYNC pin should be tied to GND in case of low sensitivity application. In this case, the sensitivity will be decreased with an half of that in normal use and the SYNC function is not available. SYNC << st 1 TS02N RSYNC nd 2 SYNC << TS02N or TS** SYNC pin option Connection Operation RSYNC Connection Normal SYNC operation with the other TSXX series / High Sensitivity Application GND No SYNC / Low Sensitivity Application VDD Forbidden ADSemiconductor Confidential 6 / 12 ADSemiconductor® TS02N (2-CH Sensitivity Calibration Capacitive Touch Sensor) 6.4 OUTPUT implementation VDD ROUT2 ROUT1 OUT2 << OUTPUT2 OUT1 << OUTPUT1 The OUT1 and OUT2 have open drain output structure. For this reason, the connection of pullup resistor ROUT is required between OUT1, OUT2 and VDD. The maximum output sink current is 4mA, so over a few kΩ must be used as ROUT1 and Rout2. Normally 10kΩ is used as ROUT1 and Rout2. The reset value of OUT1 and OUT2 is high in normal situation, and the value is low when a touch is detected on CS1 or CS2. ADSemiconductor Confidential 7 / 12 ADSemiconductor® TS02N (2-CH Sensitivity Calibration Capacitive Touch Sensor) 7 Recommended Application Two channel touch key board can be designed by using only one TS02N. The TS02N is embedded intelligent internal power reset circuit that makes possible to save circuit cost because of reducing external components for reset. The sensitivity calibration operation can help to prevent abnormal detection caused by external noise, temperature variation, and supply voltage drop. TS02N Application Example Circuit VDD periodic voltage ripple over 50mV and the ripple frequency is lower than 10 kHz can cause wrong sensitivity calibration. To prevent above problem, power (VDD, GND) line of touch circuit should be separated from other circuit. Especially LED driver power line or digital switching circuit power line certainly should be treated to be separated from touch circuit. When TS02N used in noisy environment, Lower RB is recommended. In PCB layout, RB should not be placed on touch pattern. If not, CB has to be connected. The RB pattern should be routed as short as possible. The CS pattern also should be routed as short as possible and the width of line might be about 0.25mm. The capacitor that is between VDD and GND is an obligation. It should be located as close as possible from TS02N. The CS pattern routing should be formed by bottom metal (opposite metal of touch PAD). The empty space of PCB must be filled with GND pattern to strengthen GND pattern and to prevent external noise from interfere with sensing frequency ADSemiconductor Confidential 8 / 12 ADSemiconductor® TS02N (2-CH Sensitivity Calibration Capacitive Touch Sensor) 7.1 Example – Power Line Split Strategy PCB Layout A. Not split power Line (Bad power line design) The noise that is generated by AC load or relay can be loaded at 5V power line. A big inductance might be appeared in case of the connection line between main board and display board is too long, moreover the voltage ripple could be generated by LED (LCD) display driver at VDD (5V). B. Split power Line (One 5V regulator used) – Recommended C. Split power Line (Separated 5V regulator used) – Strongly recommended ADSemiconductor Confidential 9 / 12 ADSemiconductor® TS02N (2-CH Sensitivity Calibration Capacitive Touch Sensor) 7.2 Example – PCB Layout (2 Channel Touch button with LED Display) J1 VDD OUT1 OUT2 1 2 3 4 VDD1 CON1 RB 510k RSY NC 2M CB 820pF SY NC U1 ROUT1 1 2 3 4 TP1 PAD RS1 200 CS1 10pF SY NC R_BIAS OUT1 OUT2 GND VDD CS1 CS2 8 OUT1 7 OUT2 6 VDD 1k LED1 VDD ROUT2 VDD 1k CVDD 1uF LED2 TP2 5 TS02N CS2 10pF RS2 200 PAD Schematic for PCB layout Components placement ADSemiconductor Confidential 10 / 12 ADSemiconductor® TS02N (2-CH Sensitivity Calibration Capacitive Touch Sensor) 8 PACKAGE DESCRIPTION 8.1 Mechanical Drawing Dimensions in millimeters 8.2 Marking Description Device Code : TS02N Type of version Channel Number Touch Switch Group Weekly Code : YY ZZ Manufacturing Year Manufacturing Week ADSemiconductor Confidential 11 / 12 ADSemiconductor® TS02N (2-CH Sensitivity Calibration Capacitive Touch Sensor) NOTES: LIFE SUPPORT POLICY AD SEMICONDUCTOR’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF AD SEMICONDUCTOR CORPORATION The ADS logo is a registered trademark of ADSemiconductor ⓒ 2006 ADSemiconductor – All Rights Reserved www.adsemicon.com www.adsemicon.co.kr ADSemiconductor Confidential 12 / 12