To address the rapidly growing market of low-power
touch-screens, ST has introduced S-Touch, a new range of touch sensor
controllers that offer simple and highly-efficient solutions
for capacitive and resistive touch-sensor functions in ultra small
packages.
S-Touch implements highly innovative signal processing techniques
for both capacitive and resistive technology to correctly detect,
process and pass the touch information to the CPU.
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In addition, the sensor lines from the device to the
application's touch pads do not require any external RC (resistor
capacitor) networks which are typically required in other solutions,
resulting in a highly cost-competitive solution.
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S-Touch devices are housed in the tiny QFN16 and QFN40 packages,
80% smaller than existing equivalent solutions, ensuring a very
compact and efficient design.
Technology
|
Part
number |
Package |
Features |
Resistive |
|
QFN16 |
8 GPIOs
and 4 additional ADCs |
Capacitive |
|
QFN40 |
12 keys and 12 stand-alone GPIOs
|
Resistive S-Touch
controllers |
S-Touch resistive touch-screen controllers use a 4-wire resistive
methodology with built-in ADCs to offer both ease of design and greater
flexibility to touch-screen applications.
STMPE811 controller
features: |
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Fast I2C (400 kHz) or SPI (1 MHz) serial interface |
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12-bit ADC for high-resolution resistive touch-screens |
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128-depth data buffering/filtering |
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Advanced movement tracking to reduce CPU/bus usage |
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Window masking allows intelligent use of screen |
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Ultra low power consumption (active <1 mA; idle < 100 μA) |
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| Capacitive S-Touch
controllers |
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S-Touch capacitive touch-key controllers use a hardwired finite
state machine approach with fully digital architecture. This results
in very low power consumption, five to ten times lower than the
conventional touch sensor solution, and ultra fast sampling time,
typically 2 ms. S-Touch capacitive touch-key controllers are suitable
for a wide range of touch-key sensing applications, such as keypads,
rotators or buttons.
STMPE1208S controller
features: |
|
Fast 400 kHz I2C interface |
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Ultra fast sampling time (typ. 2 ms) |
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Highly innovative self-auto calibration method enables high tolerance
to environmental changes such as temperature or PCB variations,
RF noise, water drops |
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Highly sensitive impedance change detection engine to ensure reliable
operation even with thick isolation coating ( -ΔC~60 fF) |
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Built-in data filtering technology with 100 levels of touch strength
detection |
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Ultra low power consumption (< 5 μA per key; active < 98
μA; idle < 60 μA) |
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Mobile phones, PDAs, notebooks |
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Portable media players, game consoles |
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Home appliances, instrumentation |
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Medical, security devices |
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Factory automation equipment |
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