Maxim's touch-screen ICs with integrated
infrared-based proximity sensing
Maxim has released the MAX11810 and MAX11811, the touch-interface
systems integrated with 4-wire touch-screen controller,
haptic controller driver, and infrared-based proximity sensing.
Designed for applications flexibility, these devices can
drive a DC motor directly or piezo elements using an external
piezo driver. The MAX11800 and MAX11801 are register-map-compatible
versions without haptic controller drivers and proximity
sensing.
Through simple register programming, the MAX11810/MAX11811
generates greater than 50,000 different haptic patterns
with a built-in haptic waveform generator. Programmable
registers eliminate the need for a dedicated interface on
the application processor or system microcontroller. This
programmability simplifies the addition of haptic feedback
to any end equipment with a touch screen.
Applications include cell phones, MP3 players, portable
media players, digital photo frames, multifunction printers,
point-of-sale and financial terminals, bar code-scanners,
card readers, and other industrial equipment. Automotive-qualified
part versions exist for use in car GPS, entertainment head
units, and rear-seat entertainment systems.
Traditional Haptic Feedback System
Haptic feedback using motors requires the application processor/system
microcontroller to drive the motor. The applications processor/microcontroller
needs to generate the haptic waveforms and send them to
the motor through a dedicated interface. This adds latency
and engages the application processor/microcontroller continuously,
not allowing it to perform other duties.
Simplified Haptic Feedback System
The MAX11810/MAX11811 has a built-in waveform generator
that creates the various haptic patterns and provides a
direct interface to the motors. This approach eliminates
the need for a dedicated interface on the application processor/microcontroller.
With an integrated H-bridge driver, the MAX11810/MAX11811
eliminates the need for an external amplifier when haptic
feedback is implemented using a DC motor. Alternatively,
if piezo elements are used to implement haptics, the MAX11810/MAX11811's
haptic-feedback output drives an external high-voltage amplification
circuit to which the piezo actuators are connected.
Automatic Validation of Touch Responses Reduces Data Transfer
and Saves Power
Unlike existing touch-screen controllers, the MAX11810/MAX11811
and MAX11800/MAX11801 reduce system power by providing digital,
on-chip processing to validate touch events before they
sent to the application processor. This automatic validation
reduces interrupt servicing of false or redundant touch
events and lowers total system power. This capability is
crucial for battery-powered end equipment.
The MAX11800/MAX11801 and MAX11810/MAX11811 support a built
in dynamic aperture feature (position hysteresis) and on-chip
FIFO. This automatic function reduces latency in the touch
response and unnecessary data transfer between the devices
and application processor or microcontroller.
Two other touch-screen controllers are part of this device
family, the MAX11802/MAX11803. These devices are register-map-compatible
versions of the MAX11800/01 but without the position hysteresis
and on-chip FIFO. MAX11802/11803 provides standard resistive,
touch-screen controller functionality.
Available in high-speed (25MHz) SPI and fast (400kHz) I²C
versions, all these devices have compatibility with virtually
any system or application processor. A wide, 1.7V to 3.6V,
single-supply operating range eliminates the need for external
supply-voltage regulators and level translators on the data
bus. A variant up to +105°C is currently being qualified
for use in automotive applications.
Operating temperature range: -40°C to +85°C
Package:
MAX11800-MAX11803: 1.6mm x 2.1mm, 12-pin TQFN and 12-pin
WLP packages. MAX11810/MAX11811: 2.1mm x 2.1mm, 20-pin TQFN
and 16-pin WLP packages.
Price:
MAX11810: Each $1.81 for 1k pieces
MAX11811: Each $1.76 for 1k pieces
MAX11800: Each $1.51 for 1k pieces
MAX11801: Each $1.46 for 1k pieces
MAX11802: Each $1.31 for 1k pieces
MAX11803: Each $1.26 for 1k pieces
Availability: Now
For more details visit www.maxim-ic.com/Touch-Screen-Controllers
(MAX11800-MAX11803) and www.maxim-ic.com/Haptics (MAX11810/MAX11811).
.
