semiconductor solutions
®
®
LDS6020
PureTouch
™
Capacitance Touch IC with Integrated
Keypad LED Drivers
The LDS6020 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.
LDS6020 Features
Versatile, accurate capacitance-
to-digital converter (CDC)
• 500 kHz sigma-delta CDC
• 13 capacitance sensor input channels
• 2 ms update rate per active sensor
Integrated keypad LED drivers
• C5-C12 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
Integrated, automatic
calibration algorithms
• Environmental compensation
• On-chip RAM to store calibration data
Integrated touch preference modes
• Strongest single touch
• Strongest two touches
• Unrestricted (all) touches
Ultra-low touch sensor
power consumption*
• Operating mode (typical):
<150 uW (VDD1=1.8V)
• Shutdown mode (typical):
<1 uW (VDD1=1.8V)
* Excludes LED driver current and I/F and voltage
dependent V
DDIO
current
IDT
®
LDS6020 PurETOuCH™ CaPaCITanCE TOuCH IC
1
VDD1
Calibration
RAM
LED Driver
Current Sources
Power-On
Reset Logic
Description
The LDS6020 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 13 sensor inputs, 8 of which are dual-purpose I/Os configurable as either capacitive sensor
inputs or keypad LED drivers, the LDS6020 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 LDS6020 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.
LDS6020
Switch
Matrix
Calibration
Engine
Sigma-Delta
CDC
C0
C1
C2
C3
C4
C5/LED0
C12/LED7
LED0-
LED7
VDD2
VSS2
VSS1
RESETB
Control and
Data Registers
TEST
VDDIO
I/F SEL
Serial Interface and
Control Logic
SD0/
SDA
SDI/
A1
SCLK/ CSB/
SCL
A0
Interrupt and GPIO Logic
500 kHz
Excitation
Source
SHIELD
GPIO
INTB
Figure 2.
LDS6020 block diagram
Flexible interface options
• SPI-compatible serial I/F
• I C-compatible serial I/F
• Separate V
DDIO
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
• V
DDIO
=1.65V - 3.6V
Applications:
• Mobile handsets and smartphones
• Personal music and media players
(MP3/MP4)
• Gaming devices
• Remote controls
• Television, audio/video
• Set-top boxes
• Multi-function printers
• Enterprise telephony
2
Integrated keypad LED drivers
The LDS6020 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 LDS6020 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 LDS6020 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
LDS6020 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).
SENSOR
PCB
VDDIO (1.65V~3.6V)
LDS6020
VDDIO
SHIELD
C0
C1
C2
C3
C4
C5/LED0
C6/LED1
C7/LED2
C8/LED3
C9/LED4
C10/LED5
floating
Host Processor
with SPI
VDD
VSS
I/F Toggle
CSB
SCLK
SDI
SDO
SSB
SCLK
MOSI
MISO
VDD2 (3.0V~5.5V)
floating
floating
INTB
RESETB
GPIO
TEST
INTB
RESETB
floating
floating
C11/LED6
C12/LED7
LED0-LED3
floating
VDD1 (1.65V~1.95V)
VDD1
VDD2
C2
C1
VSS1
VSS2
C1=C2: > 1uF
Figure 2.
LDS6020 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.
®
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