TTP224N Datasheet, PDF (5/10 Pages) Tontek Design Technology – 4 KEY TOUCH PAD DETECTOR IC

Preliminary
TTP224N
TonTouch^TM
FUNCTION 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 offers some methods for adjusting the 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 scope.
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 Cs0~Cs3 (please see the down figure)
Under other conditions are fixed. Add the capacitors Cs0~Cs3 can fine tune the sensitivity for
single key, that lets all key’s sensitivity identical. When do not use any capacitor to VSS, the
sensitivity is most sensitive. When adding the values of Cs0~Cs3 will reduce sensitivity in the
useful range (0≦Cs0~Cs3≦50pF).
ELECTRODE
K0
Cs0
K1
Cs1
K2
Cs2
K3
Cs3
VDD
TP0
TP1
TP2
TP3
AHLB
TOG
LPMB
VDD _TPQ0
TPQ1
TPQ2
TPQ3
TPQ0D
TPQ2D
VREG
SM
OD
REGEN
DIS13
MOT0
VSS ^MOT1
2. Output mode(By TOG, OD, AHLB pad option)
The TTP224N outputs(TPQ0~TPQ3) has direct mode active high or low by AHLB pad option, has
toggle mode by TOG pad option and has open drain(have diode protective circuit) mode by OD pad
option. Another TPQ0D, TPQ2D are open drain active low output pins have no diode protective
circuit.
TOG OD AHLB Pad TPQ0~TPQ3 option features
Remark
0
1
0 Direct mode, CMOS output active high output
Default
0
1
1 Direct mode, CMOS output active low output
0
0
0 Direct mode, Open drain active high output
0
0
1 Direct mode, Open drain active low output
1
1
0 Toggle mode, COMS output, Power on state=0
1
1
1 Toggle mode, COMS output, Power on state=1
1
0
0 Toggle mode, Power on state high-Z, Active high
1
0
1 Toggle mode, Power on state high-Z, Active low
2014/06/05
Page 5 of 10
Ver :3.1