semiconductor solutions
LDS6025
PureTouch
™
Capacitance Touch IC with
Integrated Keypad LED Drivers
The LDS6025 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.
Description
The LDS6025 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 10 sensor inputs, 5 of which are dual-purpose I/Os configurable as either capacitive sensor
inputs or keypad LED drivers, the LDS6025 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 LDS6025 is offered with both SPI-compatible and
I
2
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.
VDD1
RESETB
TEST
VDDIO
I/F SEL
SHIELD
LED0-
LED4
VSS2
VDD2
C1
C0
C5/LED0
C9/LED4
VSS1
Switch
Matrix
Serial Interface and
Control Logic
Interrupt and GPIO Logic
500 kHz
Excitation
Source
Calibration
RAM
Control and
Data Registers
LDS6025
Power-On
Reset Logic
Calibration
Engine
Sigma-Delta
CDC
C4
INTBGPIOCSB/
A0
SCLK/
SCL
SDI/
A1
SD0/
SDA
LED Driver
Current Sources
Figure 1. LDS6025 block diagram
1
IDT
®
LDS6025 PURETOUCH™ CAPACITANCE TOUCH IC
LDS6025 Features
Versatile, accurate capacitance-
to-digital converter (CDC)
• 500kHzsigma-deltaCDC
• 10capacitancesensorinputchannels
• 2msupdaterateperactivesensor
Integrated keypad LED drivers
• C5-C9sensorinputscongurable
as keypad LED drivers
• 7.75mAmaximumdrivingcurrent
(upto39mAavailablebyconnecting
multiple outputs to a single LED)
• Flexibledimmingcontrol
• Processor-freesynchronization
with touch events
Integrated, automatic
calibration algorithms
• Environmentalcompensation
• On-chipRAMtostorecalibrationdata
Integrated touch preference modes
• Strongestsingletouch
• Strongesttwotouches
• Unrestricted(all)touches
Ultra-low touch sensor
power consumption*
• Operatingmode(typical):
<150 uW (VDD1=1.8V)
• Shutdownmode(typical):
<1 uW (VDD1=1.8V)
* Excludes LED driver current and I/F and voltage
dependent V
DDIO
current
