MTCH102 Datasheet, PDF (6/37 Pages) Microchip Technology – 2, 5 and 8-Channel Proximity/Touch Controller Data Sheet

MTCH102/5/8
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 kΩ 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).
DS40001793C-page 6
Preliminary
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