LDS6028 Datasheet, PDF (1/2 Pages) Integrated Device Technology – PureTouch™ Capacitance Touch IC with Integrated Keypad LED Drivers

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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 capacitance-
to-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
and I²C-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
• 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^® LDS6028 PureTouch™ Capacitance Touch IC
Power-On
Reset Logic
LDS6028
Calibration
Engine
Sigma-Delta
CDC
VDD1
VSS1
RESETB
TEST
Calibration
RAM
LED Driver
Current Sources
LED0-
LED7
Control and
Data Registers
C0
C1
C6
C7/LED0
C14/LED7
VDD2
VSS2
VDDIO
I/F SEL
Serial Interface and
Control Logic
Interrupt and GPIO Logic
SD0/ SDI/ SCLK/ CSB/
SDA A1 SCL A0
Figure 1. LDS6028 block diagram
GPIO
INTB
1
500 kHz
Excitation
Source
SHIELD