Capacitive sense buttons match mechanical switches on cost

March 26, 2014 // By Graham Prophet
Cypress Semiconductor recently announced additional devices in its CapSense Controller series; low-cost devices that require no coding, allowing you to implement elegant, reliable user interfaces, with good noise immunity, proximity sensing and water tolerance

CapSense CY8CMBR3x controllers controllers, Cypress says, enable sleek and robust capacitive buttons, sliders and proximity sensors. They are part of Cypress’s Mechanical Button Replacement (MBR) family, which uses Cypress’s SmartSense Auto-tuning algorithm to completely eliminate the requirement for manual system tuning. SmartSense Auto-tuning enables automatic tuning of more than 10 parameters to achieve optimal touch sensing performance. The CY8CMBR3x devices are supported by Cypress’s EZ-Click software tool, which combines GUI-based configuration, product debug and production-line testing with no firmware development required. Cypress has the CY3280-MBR3 kit for $25, allowing engineers to evaluate the family’s advanced features. The kit also provides additional debug and test options, including the ability to vary trace lengths, add parasitic capacitance and change overlay thickness.

Cypress adds that you, “no longer have to make a choice between cost and performance, but instead can use low-cost devices with advanced features and proven reliability from the market leader.”

The controllers can implement up to 16 capacitive buttons or up to eight capacitive buttons while driving eight LEDs. Designers can add to the devices to add up to two proximity sensors with a 30-cm sensing distance for wake-on-approach applications. The controllers feature Flanking Sensor Suppression (FSS) that eliminates false touches when buttons are closely spaced.

Devices in the CapSense MBR family deliver robust sensing in noisy environments using Cypress’s patented CapSense Sigma-Delta (CSD) sensing method, ensuring superior immunity to conducted and radiated noise with a signal-to-noise ratio of greater than 100:1. Operating from 1.8V to 5.5V, the devices are ideal for a wide range of regulated and unregulated battery applications, including single coin cell battery operation. The controllers also feature an integrated voltage regulator to address power supply noise, as well as filters for any spurious noise. They are available in 8-pin SOIC, 16-pin QFN, 16-pin SOIC or 24-pin QFN packages.