SX8644_11 Datasheet, PDF (1/78 Pages) Semtech Corporation – Ultra Low Power, Capacitive Button and Slider Touch Controller (12 sensors) with Enhanced LED Drivers

SX8644
Ultra Low Power, Capacitive Button and Slider
Touch Controller (12 sensors) with Enhanced LED Drivers
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
GENERAL DESCRIPTION
The SX8644 is an ultra low power, fully integrated
12-channel solution for capacitive touch-buttons and
slider applications. Unlike many capacitive touch
solutions, the SX8644 features dedicated capacitive
sense inputs (that requires no external components)
in addition to 8 general purpose I/O ports (GPIO).
Each GPIO is typically configured as LED driver with
independent PWM source for enhanced lighting
control such as intensity and fading.
The SX8644 includes a capacitive 10 bit ADC analog
interface with automatic compensation up to 100pF.
The high resolution capacitive sensing supports a
wide variety of touch pad sizes and shapes and
allows capacitive buttons to be created using thick
overlay materials (up to 5mm) for an extremely
robust and ESD immune system design.
The SX8644 incorporates a versatile firmware that
was specially designed to simplify capacitive touch
solution design and offers reduced time-to-market.
Integrated multi-time programmable memory
provides the ultimate flexibility to modify key firmware
parameters (gain, threshold, scan period, auto offset
compensation… ) in the field without the need for
new firmware development.
The SX8644 supports the 400 kHz I²C serial bus
data protocol and includes a field programmable
slave address. The SX8644 is available in a tiny
MLPQ 5mm x 5mm and a LQFP 7mm x 7mm
package. The small footprints make it an ideal
solution for portable, battery powered applications
where power and density are at a premium.
KEY PRODUCT FEATURES
 Complete Twelve Sensors Capacitive Touch Controller for
Buttons and Slider
ƒ Pre-configured for 6 Buttons and a Slider
ƒ 8 LED Drivers with Individual Intensity, Fading Control
and Autolight Mode
ƒ 256 steps PWM Linear and Logarithmic control
 High Resolution Capacitive Sensing
ƒ Up to 100pF of Offset Capacitance Compensation at
Full Sensitivity
ƒ Capable of Sensing through Overlay Materials up to
5mm thick
 Extremely Low Power Optimized for Portable Application
ƒ 8uA (typ) in Sleep Mode
ƒ 80uA (typ) in Doze Mode (Scanning Period 195ms)
ƒ 220uA (typ) in Active Mode (Scanning Period 30ms)
 Programmable Scanning Period from 15ms to 1500ms
 Auto Offset Compensation
ƒ Eliminates False Triggers due to Environmental
Factors (Temperature, Humidity)
ƒ Initiated on Power-up and Configurable Intervals
 Multi-Time In-Field Programmable Firmware Parameters
for Ultimate Flexibility
ƒ On-chip user programmable memory for fast, self
contained start-up
 "Smart" Wake-up Sequence for Easy Activation from Doze
 No External Components per Sensor Input
 Internal Clock Requires No External Components
 Differential Sensor Sampling for Reduced EMI
 400 KHz Fast-Mode I²C Interface with Interrupt
 -40°C to +85°C Operation
TYPICAL APPLICATION CIRCUIT
APPLICATIONS
 Notebook/Netbook/Portable/Handheld computers
 Cell phones, PDAs
 Consumer Products, Instrumentation, Automotive
 Mechanical Button Replacement
ORDERING INFORMATION
Part Number
Temperature
Range
Package
SX8644I05AWLTRT¹ -40°C to +85°C Lead Free MLPQ-W32
SX8644I05ALPTRT² -40°C to +85°C Lead Free LQFP32
1 _{3000 Units/reel}
2 _{2500 Units/reel}
* This device is RoHS/WEEE compliant and Halogen Free
Revision 7_5, February 11
© 2011 Semtech Corp.
1
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