The TMA568 touchscreen controller from Cypress Semiconductor Corp. supports writing and drawing with a 2.0-mm-tip passive stylus, enabling touchscreens to capture characters as small as 7 mm. This capability is important for writing in languages that require enhanced character recognition for reliable text input, such as Chinese and Japanese. The controller also adds a palm rejection feature to the Cypress's Gen5 family that recognizes a user’s palm touching the screen and prevents unintended touch inputs.
The TrueTouch Gen5 family’s ChargerArmor feature delivers 40 volt peak-to-peak (Vpp) charger noise immunity, measured from 1 to 500 kHz with an ultra-thin 0.5-mm cover lens and a finger-size up to 22 mm—the most stringent specifications used to measure any touchscreen controller, according to the company. The new TMA568 controller integrates 58 sense I/Os and 21 parallel receive channels, enabling scanning of the entire panel in a single pass. The controller provides precise tracking of smaller fingers and styluses by allowing for tight spacing of touchscreen sensors, and it supports screens up to 8.3 inches at a 5.0-mm sensor pitch.
The TMA568 controller is based on the 32-bit ARM Cortex M-Core processor that is known for high-efficiency MIPS/mW, and boasts 120-Hz refresh rates, and averages low power consumption of 12 mW in active mode and 15 uW in deep-sleep mode. Gen5 controllers drive the touchscreen at 10V and at high frequency with narrow-band, single-pass scanning and advanced hardware DSP filtering.