SX8647 Ultra Low Power, Capacitive Wheel Touch Controller (8 sensors) with Enhanced LED Drivers ADVANCED COMMUNICATIONS & SENSING DATASHEET GENERAL DESCRIPTION KEY PRODUCT FEATURES The SX8647 is an ultra low power, fully integrated 8- Complete Eight Sensors Capacitive Touch Controller for a channel solution for capacitive touch wheel Wheel applications. Unlike many capacitive touch solutions, Pre-configured for a Wheel the SX8647 features dedicated capacitive sense 8 LED Drivers with Individual Intensity, Fading Control inputs (that requires no external components) in and Autolight Mode addition to 8 general purpose I/O ports (GPIO). Each GPIO is typically configured as LED driver with 256 steps PWM Linear and Logarithmic control independent PWM source for enhanced lighting High Resolution Capacitive Sensing control such as intensity and fading. Up to 100pF of Offset Capacitance Compensation at Full Sensitivity The SX8647 includes a capacitive 10 bit ADC analog Capable of Sensing through Overlay Materials up to interface with automatic compensation up to 100pF. 5mm thick The high resolution capacitive sensing supports a Extremely Low Power Optimized for Portable Application wide variety of touch pad sizes and shapes and 8uA (typ) in Sleep Mode allows capacitive wheels to be created using thick overlay materials (up to 5mm) for an extremely 80uA (typ) in Doze Mode (Scanning Period 195ms) robust and ESD immune system design. 175uA (typ) in Active Mode (Scanning Period 30ms) Programmable Scanning Period from 15ms to 1500ms The SX8647 incorporates a versatile firmware that Auto Offset Compensation was specially designed to simplify capacitive touch Eliminates False Triggers due to Environmental solution design and offers reduced time-to-market. Factors (Temperature, Humidity) Integrated multi-time programmable memory Initiated on Power-up and Configurable Intervals provides the ultimate flexibility to modify key firmware Multi-Time In-Field Programmable Firmware Parameters parameters (gain, threshold, scan period, auto offset compensation ) in the field without the need for for Ultimate Flexibility new firmware development. On-chip user programmable memory for fast, self contained start-up The SX8647 supports the 400 kHz IC serial bus Smar Wake-up Sequence for Easy Activation from Doze data protocol and includes a field programmable No External Components per Sensor Input slave address. The tiny 4mm x 4mm footprint makes Internal Clock Requires No External Components it an ideal solution for portable, battery powered Differential Sensor Sampling for Reduced EMI applications where power and density are at a 400 KHz Fast-Mode IC Interface with Interrupt premium. -40C to +85C Operation TYPICAL APPLICATION CIRCUIT APPLICATIONS Notebook/Netbook/Portable/Handheld computers Cell phones, PDAs Consumer Products, Instrumentation, Automotive ORDERING INFORMATION Part Number Temperature Package Range 1 SX8647I05AULTRT -40C to +85C Lead Free MLPQ-UT28 1 3000 Units/reel * This device is RoHS/WEEE compliant and Halogen Free Revision 7 6, February 10 2010 Semtech Corp. www.semtech.com 1 SX8647 Ultra Low Power, Capacitive Wheel Touch Controller (8 sensors) with Enhanced LED Drivers ADVANCED COMMUNICATIONS & SENSING DATASHEET Table of Contents GENERAL DESCRIPTION........................................................................................................................ 1 TYPICAL APPLICATION CIRCUIT ............................................................................................................ 1 KEY PRODUCT FEATURES..................................................................................................................... 1 APPLICATIONS....................................................................................................................................... 1 ORDERING INFORMATION...................................................................................................................... 1 1 GENERAL DESCRIPTION............................................................................................................... 4 1.1 Pin Diagram 4 1.2 Marking information 4 1.3 Pin Description 5 1.4 Simplified Block Diagram 6 1.5 Acronyms 6 2 ELECTRICAL CHARACTERISTICS ................................................................................................. 7 2.1 Absolute Maximum Ratings 7 2.2 Recommended Operating Conditions 7 2.3 Thermal Characteristics 7 2.4 Electrical Specifications 8 3 FUNCTIONAL DESCRIPTION........................................................................................................ 10 3.1 Quickstart Application 10 3.2 Introduction 10 3.2.1 General 10 3.2.2 GPIOs 11 3.2.3 Parameters 11 3.2.4 Configuration 11 3.3 Scan Period 12 3.4 Operation modes 12 3.5 Sensors on the PCB 14 3.6 Wheel Information 15 3.6.1 Wheel Information 15 3.7 Analog Sensing Interface 17 3.8 Offset Compensation 18 3.9 Processing 19 3.10 Configuration 19 3.11 Power Management 21 3.12 Clock Circuitry 21 3.13 I2C interface 21 3.14 Reset 22 3.14.1 Power up 22 3.14.2 RESETB 22 3.14.3 Software Reset 23 3.15 Interrupt 24 3.15.1 Power up 24 3.15.2 Assertion 24 3.15.3 Clearing 24 3.15.4 Example 25 Revision 7 6, February 10 2010 Semtech Corp. www.semtech.com 2