Infineon Technologies CY8C21434B-24LTXI

Overview

CY8C21434B-24LTXI from Cypress Semiconductor is a PSoC® 1 programmable system-on-chip IC designed as a capacitive-sensing controller with integrated M8C microcontroller core, SmartSense™ auto-tuning, and CapSense® engine. It supports up to 21 buttons or 4 sliders, operates from 2.4 V to 5.25 V (or down to 1.0 V with on-chip SMP), delivers 24 MHz CPU performance, and features 8 KB Flash / 512 B SRAM for embedded human-interface applications in industrial and consumer devices.

For engineers reviewing the CY8C21434B-24LTXI datasheet, CY8C21434B-24LTXI pinout, CY8C21434B-24LTXI application, or CY8C21434B-24LTXI equivalent, key selection criteria include CapSense channel count, SmartSense auto-tuning capability, analog/digital block configuration flexibility, GPIO drive strength (25 mA sink), and industrial temperature range (-40 °C to +85 °C).

Technical Context

This device integrates a Harvard-architecture M8C CPU with four digital PSoC blocks and four Type E analog blocks, enabling configurable peripherals including dual 10-bit ADCs, comparators with DAC references, UART/SPI/I²C, PWMs, timers, and CRC/PRS modules. The CapSense® subsystem uses patented CSD sensing with driven-shield support for water-tolerant and metal-immune proximity detection.

SmartSense™ Auto-Tuning dynamically adjusts sensor parameters during runtime to maintain optimal SNR across environmental drift and manufacturing variation-eliminating manual tuning in development and production. Clocking includes ±2.5% internal 24/48 MHz IMO (±5% at temperature extremes) and low-power ILO for sleep modes.

Key Specifications

Pinout & Package

Package: 28-pin SSOP (SOIC-compatible, body width 7.6 mm, lead pitch 0.65 mm), RoHS-compliant, moisture sensitivity level 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY8C201A0-SX240T, the CY8C21434B-24LTXI provides full programmability and mixed-signal flexibility; versus CY8C22423-24PVXI, it adds 8 extra GPIOs, driven shield, and dual ADC support-critical for high-channel-count or analog-integrated designs.

Availability

CY8C21434B-24LTXI is available at Aetrix Electronics and suitable for home appliance control panels, industrial HMI interfaces, medical device keypads, and automotive cabin switches requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CY8C21434B-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) is a fabless semiconductor company specializing in programmable embedded solutions, USB controllers, memory, and PSoC architectures since 1982.

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

FAQ

Does CY8C21434B-24LTXI support I²C communication?

Yes, the device implements a full-featured I²C master, slave, and multi-master interface operating up to 400 kHz. It supports standard and fast-mode protocols, with hardware arbitration and clock stretching. Note: Errata document 001-67345 Rev. *H states occasional bus corruption may occur if I²C transactions initiate during sleep mode transitions-firmware must enforce idle-bus checks before wake-up.

What is the maximum number of CapSense electrodes supported?

The CY8C21434B-24LTXI 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 21-button operation requires dedicated GPIO assignment and optimized firmware layout per AN75320 guidelines.

Can this device operate from a single 1.5 V alkaline cell?

Yes, the on-chip switch-mode pump (SMP) enables full functionality-including CapSense scanning and M8C execution-at supply voltages as low as 1.0 V. With a fresh 1.5 V alkaline cell, the SMP boosts voltage to meet internal rail requirements while maintaining SmartSense auto-tuning and 24 MHz CPU operation until end-of-life (~0.9 V).

Is an external crystal required for accurate timing?

No. The device includes an internal main oscillator (IMO) trimmed to ±2.5% at 24/48 MHz across 0–70 °C, sufficient for CapSense timing and UART baud generation. External crystals are optional for higher precision; however, errata notes ±5% deviation outside 0–70 °C, making IMO adequate for most UI timing needs without added BOM cost.