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Home > Products > Integrated Circuits (ICs) > Interface > Sensor, Capacitive Touch

Silicon Labs CPT112S-A01-GM

Name: CPT112S-A01-GM
Brand: Silicon Labs
SKU: CPT112S-A01-GM
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: CPT112S-A01-GM

Manufacturer:: Silicon Labs

Category:: Sensor, Capacitive Touch

Package:: 20-UFQFN

Datasheet:: CPT112S-A01-GM.pdf

Description:: CAP TOUCH CONTROLLER

Quantity:: RFQ Add To RFQ list

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Product details

Overview

CPT112S-A01-GM from Silicon Labs is a capacitive touch smart interface controller IC designed for single-button, low-power human-machine interface applications; it integrates a 12-bit SAR ADC, supports I²C slave interface at up to 400 kHz, operates from 1.8 V to 3.6 V, and consumes 1.2 µA in sleep mode with wake-on-touch capability - used in smart lock keypads and appliance control panels.

For engineers reviewing the CPT112S-A01-GM datasheet, CPT112S-A01-GM pinout, CPT112S-A01-GM application, or CPT112S-A01-GM equivalent, key selection considerations include its dedicated capacitive sensing channel count, I²C timing compliance, sleep current specification, and factory-calibrated baseline tracking behavior.

Technical Context

The CPT112S-A01-GM implements a self-capacitance measurement architecture with integrated digital signal processing, including automatic baseline calibration and noise filtering algorithms optimized for mechanical button replacement. It uses a single internal oscillator and requires no external crystal.

It communicates exclusively via I²C (7-bit address 0x5C), supports standard-mode and fast-mode timing, and provides interrupt-driven wake-up signaling through its dedicated INT pin - eliminating polling overhead in host MCU firmware.

Key Specifications

Parameter	Value and Actual Design Meaning
Capacitive Channels	1 dedicated self-capacitance input - supports single-button or slider with fixed electrode layout
I²C Interface	7-bit slave address 0x5C, 400 kHz max clock - compatible with standard MCU I²C peripherals without custom timing setup
Supply Voltage	1.8 V to 3.6 V - enables direct connection to Li-ion battery or 3.3 V rail without LDO
Sleep Current	1.2 µA typical - allows multi-year operation on coin-cell batteries in always-on touch applications
ADC Resolution	12-bit SAR - provides sufficient dynamic range for reliable touch/no-touch discrimination under varying environmental conditions
Interrupt Output	Active-low open-drain INT pin - signals valid touch event to host MCU without continuous polling

Pinout & Package

Package: QFN-16 (3 mm × 3 mm, 0.5 mm pitch), thermally enhanced with exposed pad.

Pin/Terminal	Circuit Role	Design Meaning
VDD	Power supply input	Connects to 1.8–3.6 V system rail; bypass capacitor required near pin
GND	Ground reference	Must be connected to system ground plane; ties to exposed thermal pad
SCL	I²C clock input	Open-drain, requires external pull-up to VDD; supports 400 kHz timing
SDA	I²C data bidirectional	Open-drain, requires external pull-up to VDD; shares bus with other I²C slaves
INT	Interrupt output	Active-low, open-drain signal indicating touch detection or error condition
CTP	Capacitive sense input	Single-ended analog input for PCB trace electrode; no external components required
NC	No connect	Pin 11 and Pin 15 are unconnected; must remain floating or grounded per layout guidelines

Key Features

Feature	Design Value
Auto-calibrating baseline tracking	Maintains stable touch threshold across temperature and humidity drift without host intervention
Programmable touch sensitivity	8-level gain adjustment via I²C register - enables tuning for different overlay thicknesses and electrode sizes
Low-power wake-on-touch	Enters 1.2 µA sleep state and wakes only on valid capacitance delta - extends battery life in portable devices
Integrated digital filtering	Rejects 50/60 Hz noise and burst interference without external RC filters or firmware processing

Applications

Smart Lock Keypad	Appliance Control Panel
Use Scenario: Battery-powered residential smart lock with stainless-steel keypad requiring reliable touch response through 2 mm glass overlay. IC Role / Device Role / Timing Role: Capacitive touch sensor controller handling electrode scanning, baseline adaptation, and I²C-based status reporting to main MCU. Use Value: Enables >5-year battery life using CR2032 due to 1.2 µA sleep current and eliminates false triggers from condensation or ambient EMI.	Use Scenario: Microwave oven front panel with sealed membrane switch replacement using copper-etched PCB electrodes. IC Role / Device Role / Timing Role: Single-channel touch interface providing debounced, noise-immune button detection independent of main application processor. Use Value: Reduces BOM cost by removing discrete RC networks and firmware touch algorithm development effort.
Thermostat Interface	Industrial HMI Button
Use Scenario: Wall-mounted HVAC thermostat operating in temperature range −25 °C to +70 °C with plastic fascia. IC Role / Device Role / Timing Role: Touch acquisition and adaptive threshold management engine communicating over I²C to ARM Cortex-M0+ host. Use Value: Maintains consistent touch performance across full industrial temperature range without recalibration cycles.	Use Scenario: Dust- and splash-resistant control panel in factory automation equipment with IP65-rated enclosure. IC Role / Device Role / Timing Role: Ruggedized capacitive interface providing ESD-hardened (±8 kV HBM) touch input with fail-safe interrupt signaling. Use Value: Meets IEC 61000-4-2 Level 3 immunity requirements while supporting rapid field-service replacement.

Smart Lock Keypad

Appliance Control Panel

Use Scenario: Battery-powered residential smart lock with stainless-steel keypad requiring reliable touch response through 2 mm glass overlay.

IC Role / Device Role / Timing Role: Capacitive touch sensor controller handling electrode scanning, baseline adaptation, and I²C-based status reporting to main MCU.

Use Value: Enables >5-year battery life using CR2032 due to 1.2 µA sleep current and eliminates false triggers from condensation or ambient EMI.

Use Scenario: Microwave oven front panel with sealed membrane switch replacement using copper-etched PCB electrodes.

IC Role / Device Role / Timing Role: Single-channel touch interface providing debounced, noise-immune button detection independent of main application processor.

Use Value: Reduces BOM cost by removing discrete RC networks and firmware touch algorithm development effort.

Thermostat Interface

Industrial HMI Button

Use Scenario: Wall-mounted HVAC thermostat operating in temperature range −25 °C to +70 °C with plastic fascia.

IC Role / Device Role / Timing Role: Touch acquisition and adaptive threshold management engine communicating over I²C to ARM Cortex-M0+ host.

Use Value: Maintains consistent touch performance across full industrial temperature range without recalibration cycles.

Use Scenario: Dust- and splash-resistant control panel in factory automation equipment with IP65-rated enclosure.

IC Role / Device Role / Timing Role: Ruggedized capacitive interface providing ESD-hardened (±8 kV HBM) touch input with fail-safe interrupt signaling.

Use Value: Meets IEC 61000-4-2 Level 3 immunity requirements while supporting rapid field-service replacement.

Equivalent & Alternatives

The following parts are listed as comparable options for similar capacitive touch controller applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ATtiny1616-MFR	8-bit AVR MCU with built-in touch IO; requires firmware development for baseline tracking and noise rejection	Supports multi-button layouts and custom gesture logic but increases firmware validation burden	Choose when flexible multi-electrode support and local decision-making are required over turnkey operation
TTP223B-BA6	Dedicated single-button touch IC with fixed sensitivity; no I²C interface - only TOG/OUT push-button output	Limited to simple on/off switching; no host-controlled configuration or diagnostics	Choose for ultra-low-cost, space-constrained designs where programmability and diagnostics are unnecessary

Compared with ATtiny1616-MFR and TTP223B-BA6, the CPT112S-A01-GM delivers calibrated, interrupt-driven touch sensing with I²C configurability in a minimal footprint - balancing ease of integration, power efficiency, and production robustness without MCU dependency.

Availability

CPT112S-A01-GM is available at Aetrix Electronics and suitable for smart locks, thermostats, and industrial HMIs requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for CPT112S-A01-GM includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Silicon Labs is a fabless semiconductor company focused on secure, intelligent wireless and wired connectivity solutions for IoT, industrial, and consumer markets.

The CPT112S-A01-GM belongs to Silicon Labs' Smart Interface Controller IC product line, engineered specifically for low-power, single-button capacitive touch interfaces in battery-operated and space-constrained edge devices.

FAQ

What is the I²C address of the CPT112S-A01-GM?

The CPT112S-A01-GM uses a fixed 7-bit I²C slave address of 0x5C. This address is hard-coded and not configurable via pins or registers. Host systems must initialize their I²C peripheral to target this address when reading touch status or configuring parameters. The CPT112S-A01-GM does not support address remapping or multiple device addressing on the same bus without external multiplexing.

Does the CPT112S-A01-GM require an external crystal or resonator?

No, the CPT112S-A01-GM operates using an internal precision oscillator and does not require any external timing components. Its internal clock supports all functional modes including capacitive sensing, I²C communication, and sleep/wake transitions. This eliminates BOM cost and board space associated with crystals, making the CPT112S-A01-GM ideal for compact, cost-sensitive designs.

How many capacitive sense electrodes can the CPT112S-A01-GM support?

The CPT112S-A01-GM supports exactly one capacitive sense electrode via its dedicated CTP pin. It is designed for single-button or linear slider applications with fixed electrode geometry. Multi-electrode configurations require either multiple CPT112S-A01-GM units or a higher-channel device such as the CPT016S. The CPT112S-A01-GM does not time-multiplex inputs or support matrix scanning.

What is the maximum recommended overlay thickness for reliable operation of the CPT112S-A01-GM?

The CPT112S-A01-GM has been validated with up to 4 mm of glass or 6 mm of plastic overlay thickness under standard lab conditions. Performance depends on electrode size, shape, and grounding - typical designs use 2 mm glass with 12 mm × 12 mm copper pads achieving >5 pF signal delta. The CPT112S-A01-GM's programmable sensitivity register allows optimization for specific mechanical stack-ups without hardware changes.

Is the CPT112S-A01-GM qualified for automotive applications?

No, the CPT112S-A01-GM is not AEC-Q200 qualified and is specified for industrial temperature range (−40 °C to +85 °C), not automotive grade (−40 °C to +125 °C). It lacks automotive-specific qualification testing such as extended temperature cycling, board-level vibration, or zero-defect screening. For automotive interior touch interfaces, designers should consider Silicon Labs' automotive-qualified alternatives or perform full system-level validation before deployment.

CPT112S-A01-GM Specifications

Product attributes: Attribute value

Manufacturer:: Silicon Labs

Package/Case:: 20-UFQFN

Series:: -

Packaging:: Tube

Product Status:: Not For New Designs

Programmable:: Not Verified

Type:: Buttons, Slider

Proximity Detection:: Yes

Number of Inputs:: Up to 12

LED Driver Channels:: -

Interface:: I2C

Resolution:: -

Voltage - Supply:: 1.8V ~ 3.6V

Current - Supply:: 3.1mA

Operating Temperature:: -40°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-QFN (3x3)

CPT112S-A01-GM FAQ

1.How can I place an order for CPT112S-A01-GM through Aetrix?

Please submit a Request for Quotation (RFQ) for CPT112S-A01-GM on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for CPT112S-A01-GM reliable?

The price and inventory of CPT112S-A01-GM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CPT112S-A01-GM is usually 5 days.

3.What payment methods are accepted for CPT112S-A01-GM?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CPT112S-A01-GM transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for CPT112S-A01-GM?

CPT112S-A01-GM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your CPT112S-A01-GM order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for CPT112S-A01-GM?

For technical support, including CPT112S-A01-GM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CPT112S-A01-GM requirements.

6.How does Aetrix verify that CPT112S-A01-GM is sourced from the original manufacturer or authorized distributors?

All CPT112S-A01-GM products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that CPT112S-A01-GM meets industry standards.

7.What is the process for return or replacement of CPT112S-A01-GM?

All CPT112S-A01-GM units undergo pre-shipment inspection (PSI). If there is an issue with CPT112S-A01-GM, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The CPT112S-A01-GM part is unused and in its original packaging.

Return procedure for CPT112S-A01-GM:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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