Capacitive touch controller with SmartSense auto-tuning
The CY8CMBR3102-SX1I is a two-button capacitive touch controller from the CapSense® Express™ SmartSense™ family, designed to replace mechanical buttons and switches in human-machine interfaces. It integrates the sensing electrodes, a proximity detection engine, and an I²C communication interface into an 8-pin SOIC package. The SmartSense™ auto-tuning algorithm handles electrode parasitic capacitance and environmental drift without manual calibration — the controller adjusts its own thresholds during operation, so the same BOM works across different panel thicknesses and overlay materials.
Supply range, temperature grade, and current draw
The 140 mA supply current is the peak draw with both channels active and the LED driver on — the actual consumption depends on the scan rate and the number of enabled sensors.
I²C interface and LED driver channel
The I²C interface operates as a slave device; the host reads touch status, proximity data, and configures the button thresholds and LED behaviour through register writes. No external ADC or GPIO expander is needed — the controller handles the full capacitive sense-to-digital conversion on-chip. One integrated LED driver channel supports a single backlight or touch-feedback LED, sinking current directly from the supply rail without an external transistor. The LED brightness and on-time are programmable over the I²C bus.
Active production and compliance documentation
No pin-compatible second-source is listed — the BOM position is locked to this order code unless a board spin is acceptable.