Infineon Technologies CY8C20637-24LQXI

Overview

CY8C20637-24LQXI from Cypress Semiconductor is a 1.8 V CapSense® controller IC with SmartSense™ auto-tuning, supporting up to 31 capacitive buttons, 6 sliders, and proximity sensing. It integrates an M8C 8-bit Harvard-architecture CPU (24 MHz), 8 KB flash/1 KB SRAM, CSD PLUS™ sigma-delta sensing engine, and driven-shield capability on five GPIOs for water-tolerant HMI designs in consumer appliances and industrial panels.

For engineers reviewing the CY8C20637-24LQXI datasheet, CY8C20637-24LQXI pinout, CY8C20637-24LQXI application, or CY8C20637-24LQXI equivalent, key selection criteria include its 0.1 pF sensitivity, 28 µA/sensor active current, 48-pin QFN package, SmartSense_EMC_PLUS runtime tuning, and I²C/SPI interface compatibility with host microcontrollers.

Technical Context

The device implements a dedicated CapSense analog subsystem with programmable CSD PLUS™ sigma-delta modulation, internal 1.0 V/1.2 V reference, and global analog mux enabling ganged proximity sensing across up to 31 inputs. Its hardware-accelerated scanning engine operates independently of the M8C CPU, reducing firmware overhead and jitter.

SmartSense_EMC_PLUS dynamically adjusts sensor parameters-including IDAC current, scan resolution, and baseline tracking-based on real-time environmental changes, eliminating manual calibration across production batches and overlay thickness variations (up to 15 mm glass). The driven-shield function on five GPIOs actively cancels parasitic capacitance, enabling robust operation near metal enclosures and wet surfaces.

Key Specifications

Pinout & Package

Package: 48-pin QFN (7 mm × 7 mm, 0.5 mm pitch), RoHS-compliant, moisture-sensitive level 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT42QT2120-MAHR and STM32F072CBT6, CY8C20637-24LQXI delivers out-of-box robustness for complex HMI with minimal firmware effort, thanks to its dedicated sensing hardware, runtime auto-tuning, and water-tolerant shield drive-reducing time-to-market by eliminating iterative board-level tuning.

Availability

CY8C20637-24LQXI is available at Aetrix Electronics and suitable for home appliance control panels, industrial HMIs, medical device interfaces, and consumer proximity-sensing systems requiring stable component supply and long-lifecycle support.

Supply support for CY8C20637-24LQXI 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) designs programmable mixed-signal ICs for embedded control, sensing, and connectivity applications, with focus on reliability and system-level integration.

CY8C20xx7/S belongs to Cypress's CapSense® controller product line, engineered specifically for robust, low-power, self-calibrating capacitive touch and proximity interfaces in harsh or variable environments.

FAQ

What is the maximum overlay thickness supported by CY8C20637-24LQXI?

The device supports up to 15 mm of glass or 5 mm of plastic overlay thickness, validated using its 0.1 pF sensitivity and CSD PLUS™ algorithm under standard lab conditions with SmartSense enabled. Performance depends on electrode size, spacing, and grounding layout-designers should follow Cypress's AN95159 layout guidelines for optimal results.

Does CY8C20637-24LQXI require external tuning components?

No external tuning components are required. The device uses internal IDACs, modulator capacitors, and programmable thresholds managed by SmartSense_EMC_PLUS. Only two external decoupling capacitors (VDD/VSS) and optional crystal (for 32 kHz timing) are needed-no RC networks, trimmers, or calibration resistors.

Can CY8C20637-24LQXI operate in deep-sleep mode while detecting proximity?

Yes-it supports proximity wake-up from deep-sleep (0.1 µA typical) using dedicated low-power analog comparators and hardware-triggered interrupt generation. The driven-shield pins remain active during sleep, enabling reliable detection of hand approach without CPU involvement until wake event occurs.

How many I²C addresses does CY8C20637-24LQXI support?

The device supports one fixed 7-bit I²C slave address (0x38) and one user-programmable address (0x39–0x3F) set via hardware straps on P4[0]–P4[2]. Address selection is non-volatile and retained across power cycles, allowing up to eight devices on a shared bus when combined with address strapping options.