SX8661Z datasheet(82/87 Pages) SEMTECH

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ADVANCED COMMUNICATIONS & SENSING

DATASHEET

Revision v4.0, February 2016

www.semtech.com

SX8661Z

Low Power, Capacitive Button Touch and Proximity Controller

(8 sensors) with LED Drivers and Analog Output

7.3

Example of Touch+Proximity Module

7.3.1

Overview

To demonstrate the proximity sensing feature of the SX8661Z/SX863x family, a module has been designed and is

illustrated in figure below.

Touch Buttons

(1.5cm pitch)

Proximity Sensor

Module Size (white area) :

sensors area + SX8633 + connector (min.)

Bicolor LEDs

(blue, orange)

Overlay

(2mm acrylic glass)

Figure 63

Touch+Proximity Module Overview

The touch button controller is running in stand-alone (i.e. without host) and uses the Autolight mode to turn LEDs

ON/OFF accordingly to the touch buttons and proximity sensing status.

7.3.2

Operation

Module operation can be seen as 5 steps which are described in figure below

1. No finger

=> No proximity detected

=> All LEDs OFF

2. Finger approaches

=> Proximity detected

=> Blue LEDs turned ON

3. Button touch

=> Orange LED turned ON

(blue+orange = pink)

4. Button release

=> Orange LED turned

OFF

5. Finger removed

=> No proximity detected

=> Blue LEDs turned OFF

Figure 64

Touch+Proximity Module Operation

Notes:

- For better user experience, bicolor LEDs have been used here but one could decide to design a module with

normal unicolor LEDs. In this case, step 3 above would simply consist in a higher (blue) intensity for the LED of

the button touched.

- For obvious demonstration purposes the overlay used here is transparent but in typical applications (TV,

Monitor, Set-top box, etc) the overlay would be opaque enough so that when LEDs are OFF (i.e. no proximity

detected) the PCB is not visible to the user.

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