Infineon Technologies CY8C20666A-24LQXIT

Overview

CY8C20666A-24LQXIT from Cypress Semiconductor is a programmable 1.8 V CapSense® controller with SmartSense™ auto-tuning, integrating an M8C 8-bit Harvard-architecture CPU (24 MHz max), 8 KB flash/1 KB SRAM, and dedicated hardware for capacitive sensing of up to 33 buttons or 6 sliders. It operates from 1.71–5.5 V, draws 28 µA/sensor in active scan mode (125 ms interval), and supports I²C (up to 400 kHz), SPI, USB 2.0 (12 Mbps), and three 16-bit timers - deployed in human-interface consumer electronics requiring robust touch response under variable EMI conditions.

For engineers reviewing the CY8C20666A-24LQXIT datasheet, CY8C20666A-24LQXIT pinout, CY8C20666A-24LQXIT application, or CY8C20666A-24LQXIT equivalent, key selection criteria include SmartSense_EMC noise immunity, configurable GPIO sink capability (25 mA per pin), integrated 10-bit ADC with internal reference, USB 2.0 compliance, and low-power Deep Sleep current (0.1 µA typical).

Technical Context

The device implements a dedicated CapSense analog block with patented CSA_EMC and CSD sensing algorithms, enabling real-time auto-tuning via SmartSense_EMC to maintain signal-to-noise ratio across manufacturing tolerances and environmental drift. Its analog mux bus connects all GPIOs to dual high-speed comparators and an internal 1 V/1.2 V reference, supporting ganged proximity sensing without external components.

System-level timing is managed by four clock sources: 6/12/24 MHz IMO, 32 kHz ILO, external 32 kHz crystal, and external clock input. The M8C core executes firmware while the CapSense block runs autonomous scanning - decoupling sensor polling from CPU load and enabling deterministic wake-up latency under 100 µs.

Key Specifications

Pinout & Package

This device is housed in a 24-pin QFN package (4 mm × 4 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are defined per the CY8C20XX6A/S datasheet Rev. *Y, page 12 (24-pin QFN with USB).

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY8C20666A-24LQXIT, the CY8C20667A offers expanded memory for complex UI logic, while the MTCH101 provides lower BOM cost and simpler qualification but forfeits programmability, USB, and analog peripherals - making the CY8C20666A optimal for mid-complexity, USB-connected touch systems requiring field-upgradable behavior.

Availability

CY8C20666A-24LQXIT is available at Aetrix Electronics and suitable for consumer remote controls, industrial HMI panels, medical patient monitors, and home appliance controls requiring stable component supply and long-term production continuity.

Supply support for CY8C20666A-24LQXIT 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

Cypress Semiconductor (now part of Infineon Technologies) designs programmable mixed-signal ICs for embedded control, sensing, and connectivity - emphasizing configurability, low power, and system integration.

This device belongs to the PSoC® CY8C20xx6A family, engineered specifically for robust, self-calibrating capacitive touch interfaces in cost-sensitive, space-constrained applications where EMI resilience and rapid time-to-market are critical.

FAQ

What is the maximum number of capacitive sensors supported by CY8C20666A-24LQXIT?

The CY8C20666A-24LQXIT supports up to 33 capacitive buttons or 6 sliders, as confirmed in the datasheet Rev. *Y section "Sensor and Package options" and validated by its 24-pin QFN configuration with 17 usable sensing inputs (P0[0]–P0[7], P1[0]–P1[7], P2[0]–P2[1]). All sensing is handled autonomously by the dedicated CapSense block without CPU overhead.

Does CY8C20666A-24LQXIT require external tuning components for CapSense operation?

No external tuning components are required. The device uses SmartSense™ Auto-tuning with patented CSA_EMC/CSD algorithms to dynamically adjust IDAC current, scan resolution, and baseline tracking in real time. Only a single 1 nF modulator capacitor (Cmod) is needed on P0[3], as specified in the hardware design guidelines (AN73034).

Can CY8C20666A-24LQXIT operate from a 3.3 V supply while maintaining USB functionality?

Yes. The device operates across 1.71–5.5 V and maintains full USB 2.0 compliance at 3.3 V. Its internal LDO regulates analog circuitry independently, and the USB transceiver meets full-speed electrical specifications (12 Mbps) across the entire voltage range - verified in AC Electrical Specifications (Section 28, datasheet Rev. *Y).

Is there a development kit available for rapid prototyping with CY8C20666A-24LQXIT?

Yes - the CY3280-20x66 Universal CapSense Controller Kit is designed specifically for CY8C20xx6A devices. It includes preloaded firmware, I²C-to-USB bridge hardware, and plug-in sensor modules (e.g., CY3280-BMM matrix board), enabling immediate tuning, data acquisition, and firmware validation without custom PCB design.