sx8643 Semtech Corporation, sx8643 Datasheet - Page 42

• Manufacturer Part Number: sx8643
• Description: Ultra Low Power, Capacitive Button Touch Controller 12 Sensors With Enhanced Led Drivers
• Manufacturer: Semtech Corporation

ADVANCED COMMUNICATIONS & SENSING
CapSensitivity0_1, CapSensitivity2_3, CapSensitivity4_5, CapSensitivity6_7, CapSensitivity8_11:
Revision 7_5, February 10
The sensitivity of the sensors can be set between 8 values. The higher the sensitivity is set the larger the value
of the ticks will be.
The minimum sensitivity can be used for thin overlay materials and large sensors, while the maximum
sensitivity is required for thicker overlay and smaller sensors.
The required sensitivity needs to be determined during a product development phase. Too low sensitivity
settings result in missing touches. Too high sensitivity settings will result in fault detection of fingers hovering
above the sensors.
The sensitivity is identical for all sensors in common sensitivity mode using the bits CapSensitivity0_1[7:4] and
can be set individually using register CapModeMisc[2].
The maximum number of ticks that can be obtained depends on the selected sensitivity as illustrated in Table
17.
Table 17
Sensitivity
Figure 41
© 2010 Semtech Corp.
1
2
3
4
5
6
7
0
ASI Maximum Tick Levels
Ultra Low Power, Capacitive Button Touch Controller
Button examples
42
Maximum Tick Level
Approximate
(12 sensors) with Enhanced LED Drivers
1000
2000
3000
4000
5000
6000
7000
8000
DATASHEET
www.semtech.com
SX8643