MTCH102-ISLASHML datasheet(6/37 Pages) MICROCHIP

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MTCH102/5/8

DS40001793C-page 6

Preliminary

 2015-2016 Microchip Technology Inc.

1.0

DEVICE OVERVIEW

The MTCH102/5/8 provides an easy way to add

proximity or touch detection to any application with

human machine interface. These devices can integrate

up to two, five and eight capacitive touch/proximity

detection sensors which can work through plastic,

wood or even metal front panels with Microchip’s

proprietary Metal over Capacitive technology. It also

supports a wide range of conductive materials as

sensors, like copper pad on PCB, silver ink, PEDOT or

carbon printing on plastic film, Indium Tin Oxide (ITO)

pad, wire/cable, etc.

The MTCH102/5/8 uses a sophisticated scan

optimization algorithm to actively attenuate noise from

the signal. The sensitivity adjustment and flexible

power mode allow users to easily configure the device

at run-time. An active-low output will communicate the

state of the sensors to a host/master MCU or drive an

indication LED.

FIGURE 1-1:

MTCH102/5/8 BLOCK DIAGRAM

1.1

Pin Description

MTIx

Connect the sensor to this input. An additional resistor

of at least 4.7 k

Ω is recommended for best noise

immunity. Sensors work best when the base

capacitance is minimized. This will maximize the

percentage change in capacitance when a finger is

added to the circuit. The recommended sensor

capacitance is 5pF to 50pF.

MTOx

The MTOx pin is an open-drain output which reports

the touch/proximity state of the corresponding MTIx

input. A pull-up resistor is required on each output. The

MTOx will pull the line low when a touch/proximity

event happens and release the line when the touch/

proximity is released.

Guard

The Guard function is multiplexed with one of the MTIx

pins. If the GC pin is floating, the Guard pin will function

as a standard MTIx sensor. If the GC pin is grounded,

the Guard pin will output a signal in-phase with the

other sensors being scanned. This has several

advantages, such as providing a mutual capacitance

coupling to the sensors to increase sensitivity, and

providing a low-impedance trace near the sensor to

absorb noise. The active guard layout should encircle

the sensor and its traces so that it will shield the sensor.

For more information about guarding and layout

guidelines, see application notes “mTouch® Sensing

Solution

Acquisition

Methods

Capacitive

Voltage

Divider”

(AN1478) and “Techniques for Robust Touch

Sensing Design”

(AN1334).

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