SX8661I07AULTRT Semtech, SX8661I07AULTRT Datasheet - Page 17

• Manufacturer Part Number: SX8661I07AULTRT
• Description: IC, Capacitive Button Touch And Proximity Controller, 8 SENSOR, MLPQ-28
• Manufacturer: Semtech

Specifications of SX8661I07AULTRT

• Controller Type: Capacitive Touch Screen
• Ic Interface Type: I2C
• Supply Voltage Range: 2.7V To 3.6V
• Operating Temperature Range: -40°C To +85°C

SX8661
Low Power, Capacitive Button Touch and Proximity Controller
(8 sensors) with LED Drivers and Analog Output
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
PCB top layer of three touch buttons sensors surrounded by a proximity sensor
Figure 10
Please refer to the layout guidelines application note [1], for more details.
3.6 Button Information
The touch buttons have two simple states (see Figure 11): ON (touched by finger) and OFF (released and no
finger press).
Buttons
Figure 11
A finger is detected as soon as the number of ticks from the ASI reaches a user-defined threshold plus a
hysteresis.
A release is detected if the tick from the ASI goes below the threshold minus a hysteresis. The hysteresis around
the threshold avoids rapid touch and release signalling during transients.
Buttons can also be used to do proximity sensing. The principle of proximity sensing operation is exactly the same
as for touch buttons except that proximity sensing is done several centimeters above the overlay through the air.
ON state means that finger/hand is detected by the sensor and OFF state means the finger/hand is far from the
sensor and not detected.
3.7 Buzzer
The SX8661 has the ability to drive a buzzer (on GPIO5) to provide an audible indication that a button has been
touched. The buzzer is driven by a square signal for approximately 30ms (default). During the first phase (15ms)
the signal’s frequency is default 4KHz while in the second phase (15ms) the signal’s frequency default is 8KHz.
The buzzer is activated only once during any button touch and is not repeated for long touches. The user can
choose to enable or disable the buzzer by configuration and define the idle level, frequencies and phase durations
(see 5.7).
Revision v3.2, January 2011
© 2011 Semtech Corp.
www.semtech.com
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