FTG2-SLP [STMicroelectronics]

The FingerTip FTG2-SLP provides an optimal mix of low power, small size, low external part counts and versatile features with unmatched true multi-touch performance in a single-chip touchscreen controller for thin flexible embedded display-touch panels.

The FingerTip FTG2-SLP uses a dedicated differential architecture with capacitance to current acquisition engine to implement the touch sensing. Coupled with the internal processor the Fingertip touchscreen controller can detect, classify and track 10 fingers touch with fast report rate and response times with a configurable channel matrix consisting of total 21 TX and 40 RX channels.

The touch acquisition analog front end has a wide dynamic range able to cope with panels of different size and configuration. This offers great flexibility to use FingerTip with new technology of embedded display-touch panels that are thinner and flexible. The FingerTip FTG2-SLP provides support for flat or curved displays through proprietary differential and node compensation hardware coupled with differential data processing techniques in firmware.

The FingerTip FTG2-SLP low-noise differential capacitive analog front-end provides enhanced noise suppression capabilities for various noise sources such as high resolution display, 3-phase noise and severe common mode noise introduced by battery chargers.

The FingerTip FTG2-SLP uses hardware and firmware ST proprietary techniques to reduce power in active and idle modes.

The FingerTip FTG2-SLP device incorporates multiple TX driving methods that can further boost the SNR and report rate.

The FingerTip FTG2-SLP supports advanced features thanks to the multi-mode sensing technology. The water rejection algorithm can detect water on the top of the screen and the device can still track one finger moving in the water without false touch or line breaking. The device supports multi finger glove operation and 2.5mm passive stylus. The device supports 20mm stable capacitive proximity.

The device also incorporates hardware SYNC on GPI3 pin which enables the touch sampling to be synchronized with the display SYNC signal. This enables it to work even with Quad High Definition displays. The device can also work in Non-SYNC condition.

The main processor implements a powerful 32-bit ARM M4 core with 192KB Flash that is able to provide a high level of overall touch performance in terms of noise rejection, response time and power consumption. It is running concurrently to the analog front end and gives ample scope for implementation of complex sensing touch tracking algorithm, advanced shape based filtering and event reporting. The 192KB flash size provides enough free space in the Flash for further customization even after implementation of ST firmware for all the features.

The device supports I2C serial interface and SPI slave interface for more flexibility.

• True multi-touch
  • Independent XY tracking with 10 simultaneous
    touches in real time
  • Supports 21TX and 40RX channels and 1 FLOAT
    pin
• Single chip solution
  • Supports 5.5 inch to 7 inch screen size with
    4mm sensor pitch
  • Supports thin flexible touch-display highly
    capacitive panel types
  • Supports LTPO display panels with dynamic
    refresh rates
• Advanced Analog Front End (AFE)
  • Simultaneous mutual sensing and self-sensing
    support on all the channels
  • Support for thin flexible touch display
    modules through proprietary node compensation
    hardware
  • Differential architecture with ability to
    configure in single-ended mode
  • Multiple scanning methods with multi-TX drive
    for high SNR and provide high noise immunity
  • High drive capability charge-pump to drive
    high capacitive panels
• High SNR
  • Very low intrinsic noise to improve the device
    SNR and provide very high sensitivity
  • Extremely strong common mode charger noise
    rejection
  • Advanced filtering techniques for high noise
    immunity
• SYNC support
  • Supports SYNC Mode and Non-SYNC Mode of
    operation
  • Supports single SYNC pin that can be used as
    VSYNC, HSYNC or Embedded VSYNC
  • Useful for quad high definition display
    synchronization during both mutual-sensing and
    self-sensing
  • Seamless support of variable display rate from
    1Hz to 120Hz
• Digital Core and Memory
  • ARM M4 core 96MHz core clock to implement all
    features with faster processing
  • 192KB Flash with GPIO6 dedicated pin for Flash
    Write enable for TEE framework
  • Advanced differential data processing for
    common mode noise immunity
  • 128KB RAM comprised of 64KB frame memory and
    64KB data)
• Advanced Features
  • Multi finger thick gloves, 2.5mm passive
    stylus, wet finger touch, water rejection, cover
    mode support
  • Finger separation ≤ 10mm
  • Capacitive proximity of 20mm
• Fast report rate
  • Flexible Report rate of 240Hz
• Low Power
  • ST proprietary Hardware and Firmware
    techniques to achieve low power
• Touch panels
  • Works with thin flexible flat or curved panels
    with touch embedded into high resolution
    displays
  • Works with LTPO display panels
• Power supply scheme
  • Dual supply operation 3.3 V and 1.8 V
• Serial interface
  • I2C compatible slave mode (100Kbps, 400Kbps,
    1Mbps)
  • 3-wire and 4-wire Mode 0 SPI interface 12MHz
    (typ.)
  • 3.3V tolerant interface for I2C and SPI
  • I/Os: RESETB, INTB hardware pins to host
    interface, 4 Digital inputs and 2 GPIOs with full
    programmability
  • All digital pins are fail safe
• ESD & TLP
  • High ESD on RX and TX pins (±8KV HBM) and
    >±3KV HBM on all other pins
  • High ESD on RX and TX pins (±1KV CDM) and
    ±500V CDM on all other pins
  • >4A TLP on all pins
• EMI
  • Low EMI <-70dBm average
  • Flicker avoidance techniques