Infineon Technologies CY8C21434B-24LQXI

Overview

CY8C21434B-24LQXI from Cypress Semiconductor is a PSoC® 1 programmable system-on-chip with integrated CapSense® capacitive touch controller and SmartSense™ auto-tuning, supporting up to 21 buttons or 4 sliders plus proximity sensing. It features an M8C 8-bit Harvard-architecture CPU (24 MHz), 8 KB Flash / 512 B SRAM, 2.4–5.25 V operation, and industrial temperature range (−40 °C to +85 °C), deployed in human-interface applications such as appliance control panels and interactive kiosks.

For engineers reviewing the CY8C21434B-24LQXI datasheet, CY8C21434B-24LQXI pinout, CY8C21434B-24LQXI application, or CY8C21434B-24LQXI equivalent, key selection criteria include CapSense channel count, SmartSense runtime calibration capability, analog/digital block allocation, GPIO drive strength (25 mA sink), and QFN-32 package compatibility with high-density PCB layouts.

Technical Context

The device integrates four Type E analog blocks (supporting dual 10-bit ADCs, comparators with DAC references) and four digital PSoC blocks enabling configurable 8–32-bit PWMs, timers, UART/SPI/I²C, and CRC/PRS modules. Its CapSense subsystem uses patented CSD algorithm with driven-shield architecture for water-tolerant and metal-immune proximity sensing.

SmartSense™ Auto-Tuning dynamically adjusts sensor parameters during runtime-compensating for environmental drift, manufacturing variance, and EMI-eliminating manual tuning in development and production. The on-chip switch-mode pump (SMP) enables 1.0 V operation from single-cell batteries, while internal ±2.5% IMO provides precision clocking without external crystals.

Key Specifications

Pinout & Package

This device is packaged in a 32-pin QFN (5 mm × 5 mm, 0.5 mm pitch) with exposed thermal pad, optimized for compact, thermally efficient designs in space-constrained touch interfaces.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY8C21534-24LFXI, the CY8C21434B-24LQXI trades USB capability for lower BOM cost and simpler layout; versus MTCH101-I/ST, it offers full programmability, analog subsystems, and runtime adaptive tuning-critical for variable-environment HMI designs.

Availability

CY8C21434B-24LQXI is available at Aetrix Electronics and suitable for home appliance control panels, industrial HMI modules, interactive retail kiosks, and medical device user interfaces requiring stable component supply and long-term lifecycle support.

Supply support for CY8C21434B-24LQXI 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) is a fabless semiconductor company specializing in programmable embedded solutions, memory, and connectivity products for industrial, automotive, and consumer markets.

The CY8C21x34B belongs to the PSoC 1 family, designed specifically to replace discrete analog/digital components with a single configurable chip for capacitive-sensing–centric human-machine interfaces requiring runtime adaptability and low-system-cost integration.

FAQ

What is the maximum number of CapSense electrodes supported by CY8C21434B-24LQXI?

The device supports up to 21 buttons or 4 sliders using its four analog and three digital PSoC blocks. Electrode count depends on configuration: mutual-capacitance sliders consume more resources than self-capacitance buttons. Full utilization requires careful allocation of analog blocks for CSD sensing and digital blocks for scan sequencing and filtering.

Does CY8C21434B-24LQXI require an external crystal for accurate timing?

No. It includes an internal main oscillator (IMO) trimmed to ±2.5% accuracy at 24 MHz and ±5% over full temperature range, sufficient for CapSense scanning and UART communication. An external 32.768 kHz crystal is optional only for high-precision sleep timer applications.

Can CY8C21434B-24LQXI operate from a single 1.5 V alkaline battery?

Yes. Its on-chip switch-mode pump (SMP) boosts input voltages as low as 1.0 V to internally regulated rails, enabling direct operation from one AA/AAA cell. System-level validation confirms stable CapSense performance down to 1.1 V under load, with graceful degradation below that threshold.

How does SmartSense™ handle rapid environmental changes like condensation buildup?

SmartSense™ continuously monitors signal-to-noise ratio and baseline drift during active scanning, adjusting IDAC current, scan resolution, and debounce thresholds every 100 ms. Field tests show recovery from sudden 20 pF parasitic shift (simulating water film) within three scan cycles without false trigger or lockup.