MTCH112
Dual Channel Proximity Touch Controller Product Brief
FEATURES
• Capacitative Proximity Detection System:
- High Signal to Noise Ratio (SNR)
- Adjustable sensitivity
- Noise Rejection Filters
- Scanning method actively optimized to
attenuate strongest noise frequencies
- Automatic calibration with optional user
presets
- Dynamic threshold management adjusts
sensitivity of sensor based on the level of
environmental noise
- Constant press calibration tracks the
expected offset when the sensor is pressed
and adjusts the threshold to automatically
achieve the best press/release behavior
- User-defined "minimum shift" values specify
the lowest amount of signal change to
activate a state transition. Automatic
thresholds never decrease below these
settings.
- Automatic Environmental Compensation
• No Required External Components
• Low-Power mode: Highly Configurable
Low-Power mode
- 1ms to 4s Sleep interval between sensor
samples
• Response Time as Low as 10 mS
• Hardware Error Detection notifies if either sensors
is shorted to V
DD
, V
SS
, or the other sensor
• Operating Voltage Range: 1.8V to 3.6V
• Operating Temperature: -40
o
C to +85
o
C
The MTCH112 uses a sophisticated optimization
algorithm to actively eliminate noise from the signal.
While the noise level is being measured, the
requirements for a proximity or touch detection are
updated to reflect the degree of uncertainty in the
readings. When a press is detected for the first time,
the threshold is automatically calibrated to choose a
smart threshold for the ‘release’ and next press. This
creates a system that dynamically optimizes the signal-
to-noise ratio for its environment.
PACKAGE TYPE
The device is available in 8-lead SOIC and DFN.
FIGURE 1:
8-PIN SOIC, DFN DIAGRAM
FOR MTCH112
SOIC, DFN
V
DD
MTO/INT
MTI0
RESET
1
MTCH112
2
3
4
8
7
6
5
V
SS
MTI1/MTGRD0
SCL
SDA
TABLE 1:
Name
V
DD
MTO/INT
MTI0
RESET
SDA
SCL
MTI1/
MTGRD0
V
SS
8-PIN DESCRIPTION
8-Pin SOIC
and DFN
1
2
3
4
5
6
7
Description
Power Supply Input
Detect Output (Active-Low)
Notification Interrupt Pin
Proximity/Touch Sensor
Input
Device Reset (Active-Low)
I
2
C™ Data
I
2
C™ Clock
Proximity/Touch Sensor
Input and Active Guard
Shield for MTI0
Ground Reference
GENERAL DESCRIPTION
The Microchip mTouch™ MTCH112 Dual Channel
Proximity/Touch Controller provides an easy way to
add proximity and/or touch sensor detection to any
application. The device implements either two
capacitive sensors or one sensor and one active guard
driver. The optional device configuration through I
2
C™
allow presets to be loaded in a production environment.
Automatic calibration routines are used by default to
choose the best options, so user configuration is not
required.
8
2012 Microchip Technology Inc.
Advance Information
DS41659A-page 1
MTCH112
TABLE 2:
CLKSEL
16 MHz
POWER CONSUMPTION
1.8V
SLEEP (S)
0
0.001
0.002
0.004
0.008
0.016
0.032
0.064
0.128
0.256
0.512
1
2
4
8
16
32
64
128
256
Typ (µA)
640
580
540
460
360
250
160
89
48
25
13
6.8
3.6
1.9
1.1
0.7
0.5
0.4
0.3
0.3
3.0V
Typ (µA)
990
900
830
710
560
390
240
140
74
38
20
11
5.5
3.0
1.8
1.1
0.8
0.7
0.6
0.5
CLKSEL
32 MHz
SLEEP (S)
0
0.001
0.002
0.004
0.008
0.016
0.032
0.064
0.128
0.256
0.512
1
2
4
8
16
32
64
128
256
3.0V
Typ (µA)
1952
1780
1630
1400
1090
760
470
270
150
75
39
20
10
5
3
1.7
1
0.8
0.7
0.6
3.6V
Typ (µA)
2350
2140
1970
1690
1320
915
570
320
170
91
46
24
12
6
3
2
1
0.9
0.7
0.6
PIN DESCRIPTION
MTI
Connect the sensor to this input. An additional resistor
of at least 4.7k is recommended for best noise
immunity. Sensors up to 40 pF in capacitance are
supported. 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.
MTO
The mTouch
TM
output pin is always driven to either V
DD
or V
SS
by the device. The MTCH112 OUTCON register
determines the behavior of the MTO/INT pin. The pin is
always active-low, but the states in which this output
occurs can be adjusted in the device's OUTCON
register. If no options are selected for output states, the
MTO pin acts as an interrupt to a master device. The
MTCH112 will pulse low for at least 1ms if any state
changes occur. Further information must be
determined by communicating through I
2
C with the
device.
MTGRD0
The waveform on MTGRD0 will shield or guard MTI0's
sensor from the effect of nearby noise sources or
power planes if MTGRD0's trace surrounds MTI0's
trace and sensor. The pin will be driven in phase with
MTI0 to minimize the voltage differential between the
two pins. This does not interfere with measuring
capacitive changes on the MTI1 sensor.
SDA/SCL
These pins are the serial data (SDA) and clock (SCL)
connections of the I
2
C interface. They should be
connected to the I
2
C master SDA and SCL signals with
a 1.5k pull-up resistor to V
DD
.
DS41659A-page 2
Advance Information
2012 Microchip Technology Inc.
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Printed on recycled paper.
ISBN: 9781620766361
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Advance Information
DS41659A-page 5
Programming Basics
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