QT511

      With the help of Quantum's patented charge-transfer methods,the QUANTUM company has come up with a new type of rotary capacitive touch 'slider' sensor IC.That is the QT511.Because it is a new type,designers could use it to create speed or volume controls, menu bars, and other more exotic forms of human interface on the panel of an appliance.In general,through a completely sealed panel it can be used to replace any form of rotary knob.
      QT511 has four applications.The first one is personal electronics.The second one is appliance controls.The third one is shaft encoders.The fourth one is automotive controls.Some features about it.The first one is rotary finger-touch 'wheel' slider control.The second one is center-button compatible signal processing.The third one is extremely simple circuit - no external active components.The fourth one is SPI slave-mode interface.The fifth one is Self-calibration and drift compensation.The sixth one is spread-spectrum operation for optimal EMC compliance.The seventh one is 2.5 - 5.5V single supply operation(very low power).The ninth one is enhanced power supply & thermal drift rejection.The tenth one is that it has 14-pin TSSOP Pb-free package.The eleventh one is compatible with clear ITO over LCD construction.The twelfth is inexpensive, simple 1-sided PCB construction possible.The last one is reference design board available.
      Some absolute maximum specifications of QT511 have been concluded as seven points.The first one is that the operating temperature range(Ta) should be within -40°C to +85°C.The second one is about storage temperature range(Ts) which should be within -55°C to +125°C.The third one is that VDD should be within -0.5 to +7.0V.The fourth one is about the max continuous pin current(any control or drive pin) should be ±20mA.The fifth one is short circuit duration to ground(any pin) could be infinite.The sixth one is short circuit duration to VDD(any pin) also could be infinite.The last one is voltage forced onto any pin which should be within -0.6V to (Vdd + 0.6) Volts.
      Some notes about QT511's operation.The first is about the sleep mode that activity on SCLK will also wake the QT511, which in turn will then wait for the /SS to rise.The second one is about its detect output pin that detection occurs when one or two of the sensing channels becomes un balanced with respect to the other channel(s) in QT511.If there is a touch at one position,that will always cause such an imbalance. However, if a signal change that is balanced among all 3 channels,that will not cause a detection.