SX8661 datasheet(37/88 Pages) SEMTECH

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ADVANCED COMMUNICATIONS & SENSING

DATASHEET

Revision v3.2, January 2011

www.semtech.com

SX8661

Low Power, Capacitive Button Touch and Proximity Controller

(8 sensors) with LED Drivers and Analog Output

PIN DESCRIPTIONS

4.1

Introduction

This chapter describes briefly the pins of the SX8661, the way the pins are protected, if the pins are analog,

digital, require pull up or pull down resistors and show control signals if these are available.

4.2

ASI pins

CAP0, CAP1,...,CAP7

The capacitance sensor pins (CAP0, CAP1,...,CAP7) are connected directly to the ASI circuitry which converts

the sensed capacitance into digital values.

The capacitance sensor pins which are not used should be left open.

The enabled CAP pins need be connected directly to the sensors without significant resistance (typical below

some ohms, connection vias are allowed).

The capacitance sensor pins are protected to VANA and GROUND.

Figure 41 shows the simplified diagram of the CAP0, CAP1,...CAP7 pins.

SX8661

sensor

ASI

CAPx

CAP_INx

VANA

Note : x = 0, 1,2,…7

Figure 41

Simplified diagram of CAP0, CAP1,...,CAP7

CN, CP

The CN and the CP pins are connected to the ASI circuitry. A 1nF sampling capacitor between CP and CN needs

to be placed as close as possible to the SX8661.

The CN and CP are protected to VANA and GROUND.

Figure 42 shows the simplified diagram of the CN and CP pins.

SX8661 Datasheet(PDF) 37 Page - Semtech Corporation