Infineon Technologies CY8C20666-24LTXI

Overview

CY8C20666-24LTXI from Cypress Semiconductor is a programmable PSoC® mixed-signal IC integrating an M8C 8-bit Harvard architecture microcontroller, dedicated CapSense® capacitive sensing block, full-speed USB 2.0 interface (12 Mbps), 32 KB Flash/2 KB SRAM, and configurable analog/digital peripherals. It operates from 1.71V to 5.5V across –40°C to +85°C and supports up to 36 GPIO with dual-mode analog/digital capability for touch buttons, sliders, and proximity sensing in human interface applications.

For engineers reviewing the CY8C20666-24LTXI datasheet, CY8C20666-24LTXI pinout, CY8C20666-24LTXI application, or CY8C20666-24LTXI equivalent, key selection criteria include USB 2.0 endpoint count (8 unidirectional + 1 bidirectional), CapSense hardware scan engine support, 24 MHz IMO accuracy (±5%), 32 kB Flash endurance (50,000 erase/write cycles), and 512-byte dedicated USB buffer allocation.

Technical Context

The device implements a dedicated hardware CapSense block with configurable charge-transfer measurement, internal 1.2 V analog reference, and global analog bus enabling simultaneous connection of any GPIO to comparators or IDACs. Its M8C core executes at up to 24 MHz with 4 MIPS throughput and integrates interrupt controller, watchdog/sleep timers, and dual oscillators (6/12/24 MHz IMO + 32 kHz ILO).

USB functionality is fully integrated with on-die 3.3 V regulator, eight unidirectional endpoints, one bidirectional control endpoint, and hardware address validation for I²C slave (50/100/400 kHz). Analog resources include two high-PSRR comparators, 8-bit delta-sigma ADC, and programmable LDO for analog supply regulation.

Key Specifications

Pinout & Package

Package: 48-pin SSOP (0.635 mm pitch) and 48-pin 7 × 7 × 1.0 mm QFN - both support full USB functionality and thermal performance up to 85°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY8C20646-24LTXI and MTCH6302-I/SS, CY8C20666-24LTXI uniquely delivers full USB HID stack execution, 32 KB firmware headroom for OTA updates, and hardware-accelerated multi-electrode scanning - making it the only option for self-contained, upgradable touch controllers requiring zero external logic.

Availability

CY8C20666-24LTXI is available at Aetrix Electronics and suitable for consumer remote controls, industrial HMIs, medical patient interfaces, and automotive cabin controllers requiring stable component supply and long-term manufacturability.

Supply support for CY8C20666-24LTXI 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, capacitive sensing, and connectivity applications, with headquarters in San Jose, CA.

The CY8C20x66 product line targets integrated human-machine interface solutions, combining CapSense hardware, USB 2.0, and flash-based programmability to replace discrete touch controllers, MCUs, and interface ICs in cost-sensitive, high-volume touch applications.

FAQ

Does CY8C20666-24LTXI support USB suspend/resume without external circuitry?

Yes. The device implements full USB 2.0 suspend/resume signaling in hardware, including automatic SOF detection, remote wakeup generation, and 2.5 mA suspend current draw. No external pull-up resistors or voltage translators are required - USB_DP and USB_DM connect directly to the connector.

Can the CapSense block operate during deep-sleep mode?

Yes. The CapSense hardware scan engine functions autonomously in Sleep mode using the 32 kHz ILO clock, consuming less than 100 µA while scanning up to 16 electrodes. Wake-up occurs only upon detection exceeding configured thresholds, preserving battery life in portable devices.

What is the maximum recommended overlay thickness for reliable touch detection?

With standard firmware tuning, the device reliably detects finger touch through 8 mm acrylic or 4 mm glass overlays. Performance depends on electrode size, spacing, and shield design - Cypress Application Note AN2292 specifies layout rules achieving >15:1 SNR at 3 mm glass thickness.

Is ISSP programming supported after soldering to PCB?

Yes. In-System Serial Programming (ISSP) is supported via dedicated P1[0]/P1[1]/P1[2] pins using standard SWD/JTAG adapters. No bootloader code is required - the SROM-based programming engine enables field firmware updates even after full system assembly and conformal coating.