IDT LDS6023

semiconductor solutions
®
®
LDS6023
PureTouch™ Capacitance Touch IC with
Integrated Keypad LED Drivers
The LDS6023 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.
LDS6023 Features
Versatile, accurate capacitanceto-digital converter (CDC)
• 500 kHz sigma-delta CDC
• 6 capacitance sensor input channels
• 2 ms update rate per active sensor
Integrated keypad LED drivers
• C3-C5 sensor inputs configurable
as keypad LED drivers
• 7.75 mA maximum driving current
(up to 23 mA available by connecting
multiple outputs to a single LED)
• Flexible dimming control
• Processor-free synchronization with
touch events
Description
The LDS6023 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 6 sensor inputs, 3 of which are dual-purpose I/Os configurable as either capacitive sensor
inputs or keypad LED drivers, the LDS6023 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 LDS6023 is offered with both SPI-compatible and
2
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
LDS6023
C1
Power-On
Reset Logic
Calibration
Engine
Sigma-Delta
CDC
C2
C3/LED0
C4/LED1
C5/LED2
VDD1
• Strongest two touches
• Unrestricted (all) touches
Switch
Matrix
• On-chip RAM to store calibration data
Integrated touch preference modes
• Strongest single touch
C0
LED Driver
Current Sources
Calibration
RAM
VSS1
LED0LED2
VDD2
VSS2
Ultra-low touch sensor
power consumption*
• Operating mode (typical): <150 uW (VDD1=1.8V)
RESETB
Control and
Data Registers
TEST
• Shutdown mode (typical): <1 uW (VDD1=1.8V)
VDDIO
* Excludes LED driver current and I/F and voltage
dependent VDDIO current
IDT® LDS6023 PureTouch™ Capacitance Touch IC
I/F SEL
Serial Interface and
Control Logic
SD0/
SDA
SDI/
A1
SCLK/ CSB/
SCL
A0
Figure 1. LDS6023 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
Flexible package options
• 28 pin 4mm x 4mm QFN,
0.8mm max height
• 28 pin 5.3mm x 10.2mm SSOP,
1.83mm 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
Integrated keypad LED drivers
The LDS6023 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 LDS6023 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 LDS6023 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
LDS6023 is a flexible solution combining the functionality of two discrete ICs into a compact 4mm x 4mm
TQFN package with 0.75mm package thickness (SSOP package also available).
• Personal music and media players
(MP3/MP4)
SENSOR
PCB
VDDIO (1.65V~3.6V)
• Gaming devices
• Remote controls
• Television, audio/video
LDS6023
• Set-top boxes
SHIELD
• Multi-function printers
• Enterprise telephony
C0
C1
C2
C3/LED0
C4/LED1
C5/LED2
Host Processor
with SPI
VDDIO
VDD
I/F SEL
VSS
CSB
SCLK
SDI
SDO
INTB
RESETB
GPIO
TEST0-1
SSB
SCLK
MOSI
MISO
INTB
RESETB
floating
floating
LED0-LED2
VDD2 (3.0V~5.5V)
VDD1 (1.65V~1.95V)
VDD1
VDD2
C2
C1
VSS1
VSS2
C1=C2: > 1uF
Figure 2. LDS6023 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-LDS6023-089