Supporting up to 12 capacitive sensor inputs in packages as small as a 3 mm x 3 mm
QFN, the CPT112S is a highly-integrated device that interfaces via I2C to the host pro-
cessor to provide a simple solution for adding capacitive touch. The device also comes
with advanced features like moisture immunity, wake-on proximity, and buzzer feedback
for an enhanced user experience. No firmware development is needed, and all the ca-
pacitive touch sense parameters can be configured using a simple GUI-based configura-
tor. By eliminating the need for complex firmware development, the CPT112S device en-
ables rapid user interface designs with minimal development effort.
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The CPT112S device is ideal for a wide range of capacitive touch applications including
the following:
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• Home appliances
• Instrument / Control panels
• White goods
• Medical equipment
• Consumer electronics
• Lighting control
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Input
Features
Capacitive Touch Sensing
Features
Mutually-
Exclusive Touch
Qualifier
en
Option for a
Multi-Button
Slider
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Proximity Wake
Input
Touch
Qualification
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I2C Output
The CPT112S device, part of the TouchXpress family, is designed
to quickly add capacitive touch via an I2C interface by eliminating
the firmware complexity and reducing the development time for ca-
pacitive sensing applications.
KEY FEATURES
• No firmware development required
• Simple GUI-based configurator
• 12 Capacitive Sensor inputs with
programmable sensitivity
• Configurable multi-button slider
• I2C interface to communicate to the host
• Lowest power capacitive sense solution
• Active — 200 µA
• Sleep — 1 µA
• Wake on proximity
• Superior noise immunity: SNR up to 270:1
• Moisture immunity
• Mutually-exclusive touch qualifier
• Button touch time-out to avoid false
touches
• Buzzer output for audible touch feedback
Configuration
Profile for each
Input
R
Baselining
Interrupt Pin
ot
Input Engine
with
12 Inputs
N
Low Power State
Machine
Touch Time-Out
Timer
Lowest power mode with feature operational:
Active
Optimized Active
Low Power Sleep
silabs.com
| Smart. Connected. Energy-friendly.
This information applies to a product under development. Its characteristics and specifications are subject to change without notice.
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Output
Features
I2C Event Buffer
Optional Buzzer
Output
Preliminary Rev. 0.2
TouchXpress™ Family
CPT112S Data Sheet
CPT112S Data Sheet
Feature List and Ordering Information
1. Feature List and Ordering Information
CP T 1 12 S
–
A 02
–
G M R
Tape and Reel (Optional)
Temperature Grade — –40 to +85 °C (G)
Firmware Revision
Hardware Revision
Capacitive Sense Features — Slider (S)
Number of Capacitive Sense Inputs
Interface Type — GPO (0), I2C (1)
TouchXpress Family
Silicon Labs Xpress Product Line
Figure 1.1. CPT112S Part Numbering
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Pb-free
The CPT112S has the following features:
• Capacitive sensing input engine with 12 inputs
• Post-sample touch qualification engine
• Configuration profile space in non-volatile memory
• I2C event buffer with interrupt pin to signal when new touch events have been qualified
• Low power state machine to minimize current draw in all use cases
• Capacitive proximity sensing input
• Buzzer output
• Mutually-exclusive touch qualifier
• Touch time-out timer
Table 1.1. Product Selection Guide
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(RoHS Compliant)
Temperature Range
Part Number
Ordering
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Yes
Yes
-40 to +85 °C
-40 to +85 °C
QFN20
QSOP24
Preliminary Rev. 0.2 | 1
CPT112S-A02-GM
CPT112S-A02-GU
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Package
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Package Type — QFN20 (M), QSOP24 (U)
CPT112S Data Sheet
Typical Connection Diagrams
2. Typical Connection Diagrams
2.1 Signal, Analog, and Power connections
Figure 2.1 Connection Diagram on page 2
shows a typical connection diagram for the power pins of CPT112S devices.
1.8-3.6 V (in)
4.7 µF and 0.1 µF
bypass capacitors
required for the power
pins placed as close to
the pins as possible.
1.8-3.6 V (in)
CPT112S
Device
VDD
GND
Host
Processor
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Electrode
1.8-3.6 V (in)
Electrode
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Figure 2.1. Connection Diagram
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EB_SCL
EB_SDA
EB_INT
CS00
CS10
Config Data
Config Clk / RSTb
Preliminary Rev. 0.2 | 2
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CPT112S Data Sheet
Typical Connection Diagrams
2.2 Configuration
The diagram below shows a typical connection diagram for the configuration connections pins. The ToolStick Base Adapter is available
on the evaluation board.
CPT112S Device
Config Clk
VDD
Config Data
GND
Figure 2.2. Configuration Connection Diagram
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ToolStick
Preliminary Rev. 0.2 | 3
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1k
CPT112S Data Sheet
Electrical Specifications
3. Electrical Specifications
3.1 Electrical Characteristics
All electrical parameters in all tables are specified under the conditions listed in
Table 3.1 Recommended Operating Conditions on page
4,
unless stated otherwise.
3.1.1 Recommended Operating Conditions
Table 3.1. Recommended Operating Conditions
Parameter
Operating Supply Voltage on VDD
Minimum RAM Data Retention
Voltage on VDD
1
Operating Ambient Temperature
Symbol
V
DD
V
RAM
Not in Sleep Mode
Sleep Mode
T
A
Test Condition
Min
1.8
—
—
–40
Note:
1. All voltages with respect to GND.
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Typ
2.4
Max
3.6
—
Unit
V
1.4
0.3
—
V
0.5
85
V
°C
Preliminary Rev. 0.2 | 4
MCU
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