Preliminary

TTP224N-ASD

TonTouch

TM

2014/06/05

Page 5 of 12

Ver:3.1

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-ASD 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).

LPMB

TOG

AHLB

SM

OD

REGEN

MOT1

MOT0

VREG

Cs3

Cs2

Cs1

Cs0

ELECTRODE

K3

K0

K1

K2

TP3

TP2

TP1

VDD

VDD

TP0

VSS

TPQ0

TPQ0D

TPQ3

TPQ2

TPQ1

2. Output mode(By TOG, OD, AHLB pad option)

The TTP224N-ASD 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 is open drain active low output pin has no diode protective

circuit.

TOG

OD AHLB

Pad TPQ0~TP3 option features

Remark

0

1

0

Direct mode, CMOS active high output

Default

0

1

1

Direct mode, CMOS 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