TTP239 Datasheet, PDF (13/16 Pages) Tontek Design Technology – 8 keys Touch Pad Detector IC

Application circuit
ELECTRODE
K7
Cs7
K6
Cs6
K5
Cs5
K4
Cs4
K3
Cs3
K2
Cs2
K1
Cs1
K0
Cs0
TTP239
32 31 30 29 28 27 26 25 24 23
1 TP7
2 TP6
3 TP5
4 TP4
5 TP3
6 TP2
7 TP1
8 TP0
TCP239
TPQ5 22
TPQ4 21
SCL 20
SDO 19
SDA 18
TPQ3 17
TPQ2 16
VREG 15
VDD 14
9 10 11 12 13
T1 T2 T3 T4 T5 T6
VDD
C1
104
P.S.：
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 power supply must be stable. If the supply voltage drift or shift quickly, maybe causing
sensitivity anomalies or false detections.
3. The material of panel covering on the PCB can not include the metal or the electric element.
The paints on the surfaces are the same.
4. The C1 capacitor must be used between VDD and VSS; and should be routed with very short
tracks to the device’s VDD and VSS pins (TTP239).
5. The capacitance Cs0~Cs7 can be used to adjust the sensitivity. The value of Cs0~Cs7 use
smaller, then the sensitivity will be better. The sensitivity adjustment must according to the
practical application on PCB. The range of Cs0~Cs7 value are 1~50pF.
6. The sensitivity adjustment capacitors（Cs0~Cs7）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.
7. When the system doesn’t use the serial output interface for TTP239, the SCL pin of TTP239 must
be connected to VDD or VSS.
2016/3/7
Page 13 of 16
Version：1.1