Infineon Technologies CY8C21634B-24LTXI

Overview

CY8C21634B-24LTXI from Cypress Semiconductor is a PSoC® 1 programmable system-on-chip with integrated CapSense® capacitive touch controller, SmartSense™ auto-tuning, and M8C 8-bit Harvard-architecture CPU running at up to 24 MHz. It supports 1–21 buttons or 0–4 sliders, operates from 2.4 V to 5.25 V (or down to 1.0 V with on-chip SMP), and features 8 KB Flash / 512 B SRAM for embedded human-interface applications in industrial and consumer devices.

For engineers reviewing the CY8C21634B-24LTXI datasheet, CY8C21634B-24LTXI pinout, CY8C21634B-24LTXI application, or CY8C21634B-24LTXI equivalent, key selection criteria include CapSense channel count, SmartSense auto-tuning capability, analog/digital block allocation, GPIO drive strength (25 mA sink), and I²C/UART/SPI peripheral availability in the 28-pin SSOP package.

Technical Context

The device integrates four digital PSoC blocks and four Type E analog blocks, enabling configurable peripherals including dual 10-bit ADCs, comparators with DAC references, 8–32-bit timers/PWMs, full-duplex UART, SPI master/slave, and I²C multi-master up to 400 kHz. All digital and analog resources connect via global interconnect buses routed to any GPIO.

CapSense functionality uses patented CSD sensing with driven-shield support for water-tolerant and metal-immune proximity detection. SmartSense_EMC auto-tuning dynamically adjusts sensor parameters during runtime to maintain performance across temperature, voltage, and manufacturing variation without manual calibration.

Key Specifications

Pinout & Package

Package: 28-pin SSOP (Small Outline Package), 300 mil width, lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY8C21434B-24LTXI and CY8C22423A-24PVXI, the CY8C21634B-24LTXI delivers higher electrode scalability, automated tuning, and superior analog resource allocation - making it optimal for first-pass-to-production touch interfaces requiring zero-touch calibration.

Availability

CY8C21634B-24LTXI is available at Aetrix Electronics and suitable for industrial HMI, medical device interfaces, and consumer appliance control panels requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for CY8C21634B-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, sensing, and connectivity, with emphasis on system-level integration and developer productivity.

The CY8C21x34B product line targets cost-sensitive, high-volume capacitive touch applications requiring self-calibrating sensor performance, flexible peripheral configuration, and minimal external components - especially where rapid UI prototyping and production ramp are critical.

FAQ

What development tools are required to program and debug the CY8C21634B-24LTXI?

PSoC Designer™ (free Windows IDE) is mandatory for configuration, code generation, and debugging. Programming requires MiniProg1 or MiniProg3; both support ISSP and full-speed emulation with 128 KB trace memory. The CY3210-PSoCEval1 evaluation kit provides hardware validation for all PSoC 1 families except CY8C25/26xxx, and includes LCD, potentiometer, and breadboarding space.

Does the CY8C21634B-24LTXI support true hardware-accelerated proximity sensing without external components?

Yes - proximity sensing is implemented natively in the CapSense block using CSD algorithm with driven shield and internal IDACs. No external transceivers, op-amps, or RC networks are needed. Detection range depends on electrode size and layout but typically achieves 3–6 cm with standard PCB traces and 1.0 mm overlay thickness.

Can the internal 24 MHz IMO be used as the primary clock source for CapSense scanning and system timing?

Yes - the internal main oscillator (IMO) is factory-trimmed to ±2.5% accuracy at 24 MHz and is the default clock for CapSense scanning, CPU execution, and most peripherals. Its stability over temperature and voltage is sufficient for production touch systems; external crystals are optional and used only when tighter timing precision is required for non-CapSense functions.

How does SmartSense™ handle manufacturing variation in PCB trace capacitance across production lots?

SmartSense_EMC auto-tuning measures baseline capacitance during power-up and periodic recalibration, then adjusts IDAC current, scan resolution, and debounce thresholds to maintain consistent finger detection SNR. It compensates for ±15% trace capacitance variation without user intervention - verified across 10,000+ units in automotive and appliance qualification testing.