Renesas Capacitive Touch Technology Detailed Specifications

What are the specifications for the Renesas Capacitive Touch Technology?

  • Renesas has developed the Capacitive Touch Sensor Unit (CTSU) IP Block in order for designers to implement Capacitive Touch interfaces in their applications when using Renesas MCUs. The CTSU is a stand-alone IP block that, once triggered, can scan multiple sensors without CPU interaction. For detailed information of the CTSU and a description of the capabilities please read the following :

    App Note : CTSU Basis of Cap Touch detection (R30AN0218EJ0100)

    A block diagram of the CTSU can be seen below :

    The specification of the CTSU is as follows :

    • Max number of sensors : 36
    • Number of CTSU blocks per MCU : 1
    • Max input clock : 32MHz (PCLKB)
    • Detection method : Switched Capacitor filter technique
    • Capacitive sensor load : 10pF to 50pF
    • Self-Capacitance support : Yes
    • Mutual-Capacitance support : Yes
    • Multi-Mode support : Yes (dynamic configuration)
    • Dedicated power regulator : Yes (Normal & Low voltage modes)
    • Spread Spectrum dithering : Yes
    • Scanning frequency : Programmable (per sensor)
    • Max overlay thickness : 10mm (sensor size and dielectric material dependant)
    • External passive requirement : 10nF (TSCAP) capacitor (1 off per MCU)
    • Series damping resistor : 1 per sensor (2Kohms maximum impedance)
    • Slider support : Yes (3 to 10 sensors)
    • Wheel support : Yes (4 or 8 sensors)
    • Proximity support : Yes (mutual capacitive mode)
    • Low power : 8uA (R01AN3191EJ0100) (1 sensor, 2MHz SCF, 100ms scan cycle)
    • Noise countermeasures : Spread spectrum switching clock, dual frequency scanning and LFSR Phase inversion)
    • Standards : Supports IEC 61000 4-3/4-6 Level 3 (5mm acrylic overlay)