The QT118H is a digital burst mode charge-transfer (QT) sensor designed specifically for touch controls; it includes all hardware and signal processing functions necessary to provide stable sensing under a wide variety of changing conditions. Only a few low cost, non-critical discrete external parts are required for operation.
Figure 1-1 shows the basic QT118H circuit using the device, with a conventional output drive and power supply connections. Figure 1-2 shows a second configuration using a common power/signal rail which can be a long twisted pair from a controller; this configuration uses the built-in pulse mode to transmit the output state to the host controller.
● Less expensive than many mechanical switches
● Projects a ‘touch button’ through any dielectric
● 100% autocal for life - no adjustments required
● No active external components
● Piezo sounder direct drive for ‘tactile’ click feedback
● LED drive for visual feedback
● 2.5 ~ 5V single supply operation
● 10µA at 2.5V - very low power drain
● Toggle mode for on/off control (via option pins)
● 10s or 60s auto-recalibration timeout (via option pins)
● Pulse output mode (via option pins)
● Gain settings in 3 discrete levels
● Simple 2-wire operation possible
● HeartBeat™ health indicator on output
● Pb-Free package
● Elevator buttons
● Toys & games
● Access systems
● Pointing devices
● Appliance control
● Security systems
● Light switches
● Industrial panels
Quantum Research Group was acquired by Atmel.
Quantum Research Group is the leading independent developer of capacitive sensing IP and solutions for user interfaces. Offering a wide variety of touch and proximity sensing solutions, Quantum Research Group is the leading independent supplier of capacitive sensing solutions. Quantum Research Group innovative touchpad navigation technologies support a wide range of markets and applications.