preliminary ttp224n - co8 tontouch tm 20 1 4 / 06 / 0 5 page 1 of 8 v er : 3 . 1 2 key touch pad detector ic general description the ttp224n - co8 ton touch tm ic is capacitive sensing design specifically for touch pad controls. the device built in regulator for touch sensor. stable sensing method can cover diversity conditions. human interfaces control panel links through non - conductive dielectric material. the main application is focused at replacing of the mechanical switch or button. the assp can independently handle the 2 touch p ads with 2 direct output pins . features ? operating voltage 2. 4 v~5.5v ? built - in regulator ? operating current, @vdd=3v no load a t low power mode typical 2 ua, at fast mode typical 6 . 5 ua ? @vdd=3v operating voltage : the response time about 6 0ms at fast mode, 16 0m s at low power mode ? sensitivity can adjust by the capacitance(0~50pf) outside for each touch pad ? provides direct mode or toggle mode active high or active low by pad option (tog/ahlb pin) . ? after power - on have about 0. 5 sec stable - time, during the time do not touch the key pad, and the function is disabled ? auto calibration for life, and the re - calibration period is about 4.0se c, when key has not be touched. application ? wide consumer products ? button key replacement
preliminary ttp224n - co8 tontouch tm 20 1 4 / 06 / 0 5 page 2 of 8 v er : 3 . 1 block diagram package list ttp224n - co8 package type is sop - 8 ,package configuration is below p in description p in no. p in name type pad description 1 tp 0 i /o touch pad input pin 2 tp 1 i /o touch pad input pin 3 ahlb i - pl output active high or low option , default:0 4 vdd p positive power supply 5 tog i - pl output type option , default:0 6 vss p negative power supply, ground 7 tpq 1 o direct output for tp1 t ouch input pin 8 tpq 0 o direct output for tp0 touch input pin note pin type i cmos input only i - pl cmos input and pull - low resister o c mos push - pull output i/o cmos i/o p power / ground tog ahlb tp0 tp1 tpq1 tpq0 regulator circuit control key-on & timing circuit system oscillator control circuit function option timing counter & circuit sensor oscillator circuit touch detecting detecting circuit reference sensor & circuit driver & mode output pkg-co8 2014/6/5 01 01 11:24:48 pkg-co8 . ttp224n-c lot no. date code tpq0 8 vss 6 tog 5 vdd 4 ahlb 3 tp0 1 7 tpq1 tp1 2
preliminary ttp224n - co8 tontouch tm 20 1 4 / 06 / 0 5 page 3 of 8 v er : 3 . 1 e lectrical c haracteristics ? ? dc /ac characteristics ( test condition at room temperature= 25 ) parameter symbol conditions rating unit operating temperature top - 4 0 ~ + 85 storage temperature t stg - 50 ~ +125 supply voltage vdd ta=25 ? c vss - 0.3 ~vss+6.0 v input voltage v in ta=25 ? c vss - 0.3 to vdd+0.3 v human body mode esd 5 kv note: vss symbolizes for system ground parameter symbol test condition min. typ. max. unit operating voltage vdd r egulator en able 2. 4 - 5.5 v internal regulator output vreg r egul ator en able 2.2 2. 3 2. 4 v operating current (no load , regulator enable ) i op1 vdd=3v , at low power mode 2 ua vdd=3v , at fast mode 6.5 ua input ports v il input low voltage 0 - 0.2 vdd input ports v ih input high voltage 0.8 - 1.0 vdd output por t sink current i ol vdd=3v, v ol =0.6v - 8 - ma output port source current i oh vdd=3v, v oh =2.4v - - 4 - ma input pin pull - low resistor r pl vdd=3v, 2 5 k ohm output response time t r vdd=3v, at fast mode 60 ms vdd=3v, at low power mode 160 ms
preliminary ttp224n - co8 tontouch tm 20 1 4 / 06 / 0 5 page 4 of 8 v er : 3 . 1 functi on description 1. sensitivity adjustment the total loading of electrode size and capacitance of connecting line on pcb can affect the sensitivity. so the sensitivity adjustment must according to the practical application on pcb. the ttp224n - co8 o ffers so me methods for adjusting t he sensitivity outside. 1 - 1 by the electrode size under other conditions are fixed. using a larger electrode size can increase sensitivity. otherwise it can decrease sensitivity. but the electrode size must use in the effective sc ope. 1 - 2 by the panel thickness under other conditions are fixed. using a thinner panel can increase sensitivity. otherwise it can decrease sensitivity. but the panel thickness must be below the maximum value. 1 - 3 by the value of cs 0~cs 1 (please see the do wn figure) under other conditions are fixed. add the capacitors c s 0~c s1 can fine tune the sensitivity for single key, that lets all keys sensitivity identical. when do not use any capacitor to vss, the sensitivity is most sensitive. when adding the values of cs 0~cs 1 will reduce sensitivity in the useful range (0 Q cs 0~cs 1 Q 50pf). 2 . output mode (by tog, ahlb pad option) the ttp224n - co8 outp uts(tpq0~tpq1 ) has direct mode active high or low by ahlb pad option , has toggle mode by tog pad option. tog ahlb pad tpq0~tp1 o ption features remark 0 0 direct mode, cmos active high output default 0 1 direct mode, cmos active low output 1 0 toggle mode, coms output, power on state=0 1 1 toggle mode, coms output, power on state=1 cs1 cs0 electrode tpq0 tpq1 tp1 tp0 k1 k0 tog ahlb vdd vdd vss
preliminary ttp224n - co8 tontouch tm 20 1 4 / 06 / 0 5 page 5 of 8 v er : 3 . 1 3 . low power mode the t tp224n - co8 i s low power mode. i t will be saving power . w hen detecting key touch, it will switch to fast mode. until the key touch is released and will keep a time about 8 sec. then it returns to low power mode. the states and timing please see below figure. ttp224n - co 8 timing diagram : timing 2009/7/31 01 01 11:09:58 timing . (not really touch) key release ~125ms ~30ms ~125ms ~30ms ~125ms tp tpq about 8sec possible key touch key release timing fast mode key touch low power mode timing low power mode timing timing fast mode vss vdd low power mode low power mode timing vss vdd
preliminary ttp224n - co8 tontouch tm 20 1 4 / 06 / 0 5 page 6 of 8 v er : 3 . 1 application circuit ps 1. on pcb, the length of lines from touch pad to ic pin shorter is better. and the lines do not parallel and cross with other lines. 2 . the material of panel covering on the pcb can n ot include the metal or the electric element. the paints on the surfaces are the same. 3 . the c1 capacitor must be used between vdd and vss; and should be routed with very short tracks to the devices vdd and vss pins . 4 . the capacitance cs0~cs 1 c an be used to adjust the sensitivity. the value of cs0~cs 1 use smaller, then the sensitivity will be better. the sensitivity adjustment must according to the practical application on pcb. the range of cs0~cs 1 value are 0~50pf. 5 . the sensitivity ad justment capacitors (c s 0~c s 1 ) must use smaller temperature coefficient and more stable capacitors. such are x7r, npo for example. so for touch application, recommend to use npo capacitor, for reducing that the temperature varies to affect sensitivity. co8-app 2014/6/5 01 01 11:56:26 co8-app . TTP224N-CO8 sop-8 TTP224N-CO8 application vdd vdd vdd vdd pad tpq0~tp1 option features toggle mode, coms output, power on state=1 toggle mode, coms output, power on state=0 open direct mode, cmos active low output direct mode, cmos active high output open ahlb open open tog option table: output mode: c1 104 k0 cs0 k1 cs1 tpq0 8 tpq1 7 vss 6 tog 5 4 vdd 3 ahlb 1 tp0 2 tp1
preliminary ttp224n - co8 tontouch tm 20 1 4 / 06 / 0 5 page 7 of 8 v er : 3 . 1 package type: so p - 8 package outline dimension
preliminary ttp224n - co8 tontouch tm 20 1 4 / 06 / 0 5 page 8 of 8 v er : 3 . 1 order information a. package form: ttp224n - co8 b. chip form: tc p224n c. wafer base: td p224 - 02 revise history 1. 2009/06/ 30 - original version v1.0 2. 2009/ 0 8 / 25 ? v2.0 add the ttp224n - co8 3. 20 10 / 06 / 08 ? v3.0 add the ttp224l - co8 4. 2014/06/05 ? v3.1 remove ttp224 - co8 and ttp224l - co8 function
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