Datasheet

9502A–AT42–07/08

AT42QT2160

For better surface moisture suppression, the outer perimeter of X should be as wide as possible,

and there should be no ground planes near the keys. The variable “T" in this drawing represents

the total thickness of all materials that the keys must penetrate.

Figure 4-6. Recommended Key Structure

Note: “T" should ideally be similar to the complete thickness the fields need to penetrate to the touch

surface. Smaller dimensions will also work but will give less signal strength. If in doubt, make the

pattern coarser. The lower figure shows a simpler structure used for compact key layouts, for

example for mobile phones. A layout with a common X drive and two receive electrodes is

depicted

4.9 Setting the Slider

4.9.1 Introduction

Groups of keys can be configured as a slider, in addition to their use as keys. The slider uses the

Y0 line of the matrix and must start at X0, with the keys placed in consecutive numerical order.

The slider can take up a programmable number of keys on the Y0 line. The remaining keys on

that Y line behave as normal.

Positional data is calculated in a customizable range of 2 bits (0-3) to 8 bits (0-255). Geometric

constraints may mean that the data will not reach the full range. Thinner dielectric or the use of

more keys in a slider will increase the data range towards the ends.

Stability of the reported position will be dependent on the amount of signal on the slider keys.

Running at higher resolutions, with a thick panel might produce a fluctuating reported position.