semiconductor solutions ® ® LDS6028 PureTouch™ Capacitance Touch IC with Integrated Keypad LED Drivers The LDS6028 PureTouch™ controller empowers system designers to create streamlined, attractive and reliable product designs with capacitive touch controls. Integrated LED drivers allow visual feedback to be implemented when a touch occurs, without the need for host intervention. LDS6028 Features Versatile, accurate capacitanceto-digital converter (CDC) • 500 kHz sigma-delta CDC • 15 capacitance sensor input channels • 2 ms update rate per active sensor Integrated keypad LED drivers • C7-C14 sensor inputs configurable as keypad LED drivers • 7.75 mA maximum driving current (up to 62 mA available by connecting multiple outputs to a single LED) • Flexible dimming control • Processor-free synchronization with touch events Description The LDS6028 is a programmable capacitance-to-digital converter (CDC) designed for use with capacitive sensor arrays implementing touch-based input controls including sliders, scroll wheels, and buttons. Featuring 15 sensor inputs, 8 of which are dual-purpose I/Os configurable as either capacitive sensor inputs or keypad LED drivers, the LDS6028 provides the flexibility to implement multiple touch inputs with integrated lighting effects using a single controller. When configured for capacitive sensing, the I/Os are directed through an integrated switch matrix to a 500 kHz sigma-delta CDC which senses changes in the external sensor array. When a sufficiently large change in capacitance occurs, a sensor activation is registered and the host processor is notified. LED lighting effects are automatically initiated by a touch event with no processor intervention required. On-chip calibration logic continuously monitors the environment and automatically adjusts on-and-off threshold levels to prevent false sensor activation. The LDS6028 is offered with both SPI-compatible 2 and I C-compatible interfaces (active interface selected by I/F select pin) and features a general-purpose input/output (GPIO) and interrupt output for additional communication with the host processor. Integrated, automatic calibration algorithms • Environmental compensation LDS6028 Integrated touch preference modes • Strongest Single Touch Power-On Reset Logic Calibration Engine Ultra-low touch sensor power consumption* • Operating mode (typical): <150 uW (VDD1=1.8V) Sigma-Delta CDC LED Driver Current Sources Calibration RAM VSS1 IDT® LDS6028 PureTouch™ Capacitance Touch IC VDD2 VSS2 Control and Data Registers TEST VDDIO dependent VDDIO current LED0LED7 RESETB • Shutdown mode (typical): <1 uW (VDD1=1.8V) * Excludes LED driver current and I/F and voltage C6 C7/LED0 C14/LED7 VDD1 • Strongest Two Touches • Unrestricted (All) Touches Switch Matrix • On-chip RAM to store calibration data C0 C1 I/F SEL Serial Interface and Control Logic SD0/ SDA SDI/ A1 SCLK/ CSB/ SCL A0 Figure 1. LDS6028 block diagram 1 Interrupt and GPIO Logic GPIO INTB 500 kHz Excitation Source SHIELD Flexible interface options • SPI-compatible serial I/F 2 • I C-compatible serial I/F • Separate VDDIO level for serial interface • GPIO and Interrupt Output Small footprint package • 40 pin 5mm x 5mm QFN, 0.8mm max height Power supply range • Touch supply (VDD1): 1.65V - 1.95V • LED supply (VDD2): 3.0V - 5.5V • VDDIO=1.65V - 3.6V Applications • Mobile handsets and smartphones • Personal music and media players (MP3/MP4) • Gaming devices Integrated keypad LED drivers The LDS6028 features integrated keypad LED drivers enabling the implementation of visual feedback for touch-based controls and fun lighting effects. The keypad LEDs may be powered either from Vbattery directly or from a regulated voltage supply. On/off transition times are programmed globally for all LEDs and maximum current may be programmed for each LED individually. LEDs may be either manually controlled or synchronized to automatically trigger when a touch event occurs. Ideal solution for portable applications The LDS6028 is optimized for minimal power consumption, with touch sensor circuits operating from a 1.8V supply voltage. In full power mode, sensor conversion and calibration occur continuously, minimizing the time between touch event and touch detection. With its ultra-low touch sensor power consumption of <150 uW (typical), the LDS6028 may be operated continuously in full power mode, eliminating the need for introduced latencies that can cause noticeable delays and degrade the user experience. The total solution footprint is also optimized for portable applications, with the functionality of multiple components consolidated into a single device. With integrated keypad LED driver functionality, the LDS6028 is a flexible solution combining the functionality of two discrete ICs into a compact 5mm x 5mm TQFN package with 0.75mm package thickness. SENSOR PCB • Remote controls VDDIO (1.65V~3.6V) • Television, audio/video • Set-top boxes • Multi-function printers LDS6028 • Enterprise telephony SHIELD floating floating C0 C1 C2 C3 C4 C5 C6 C7/LED0 C8/LED1 C9/LED2 Host Processor with SPI VDDIO VDD I/F SEC VSS CSB SCLK SDI SDO INTB RESETB GPIO TEST0-1 SSB SCLK MOSI MISO INTB RESETB floating floating C10/LED3 LED0-LED3 VDD2 (3.0V~5.5V) floating C11/LED4 floating C12/LED5 floating C13/LED6 floating C14/LED7 VDD1 (1.65V~1.95V) VDD1 VDD2 C2 C1 VSS1 VSS2 C1=C2: > 1uF Figure 2. LDS6028 application diagram Discover what IDT know-how can do for you. www.IDT.com/go/touch ® © 2009 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice. IDT and the IDT logo are registered trademarks of Integrated Device Technology, Inc. All other brands, product names and marks are or may be trademarks or registered trademarks used to identify products or services of their respective owners. Printed in USA 08-09/MG/BWD/PDF_r7_v1 FLYR-LDS6028-089