Designed for use in a wide range of popular applications, these advanced proximity
switches use a patented method for detection to deliver enhanced performance.
NXP capacitive
proximity switches
PCx8885
Dynamic touch and proximity switches
with eight sensor channels
KEY FEATURES
` Support for matrix arrangement of up to 28 sensors with a
single IC
` Adjustable response time and sensitivity
` Continuous autocalibration
` AEC-Q100 qualified (PCA8885TS)
` Digital processing method
` Copes with up to 6 mm of acrylic glass or 10 mm of glass
` I
2
C Fast-mode plus (Fm+) compatible interface (up to 1 MHz)
` Can be configured as two cascaded ICs for 8 x 8 matrix
` Interrupt via output or signaling over I
2
C bus
` Large supply voltage range (V
DD
= 2.5 to 5.5 V)
` Ideal of battery-powered operation (I
DD
~ 10 µA)
` Sleep mode (I
DD
< 100 nA)
APPLICATIONS
` White goods, washing machines, water heaters
` Multimedia units, TVs, audio equipment
` Self-care medical devices
` Gaming, toys
` Industrial equipment
` Home automation
` Automotive: climate control, HVAC, center stack, car
entertainment unit, mirror control
The NXP PCF8885TS and PCA8885TS are capacitive 8-channel
proximity switches that use a patented method (EDISEN) to
detect a change in capacitance on remote sensing plates.
Changes in the static capacitances (as opposed to changes in
the dynamic capacitances) are automatically compensated by
using continuous autocalibration.
Both switches are well suited to a wide range of applications,
including man-to-machine interfaces and hermetically sealed
units. They deliver reliable performance in harsh environments
and can be used for system wake-up and activation. They
also support use with single buttons, slider wheels, and key
matrixes. The PCA8885TS is an AEC-Q100 qualified touch
switch optimized for use in automotive applications.
Both versions interface to the system controller via an I
2
C-bus
operating at up to 1 MHz (Fm+), and generate an interrupt
whenever a touch has occurred. Onboard sensor pads or
remote sensing plates, connected via coaxial cables, can be
used for touch or proximity sensing.
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© 2014 NXP Semiconductors N.V.
All rights reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The
information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and
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Date of release: April 2014
Document order number: 9397 750 17551
Printed in the Netherlands
The eight input channels operate independently of each
other. There is also a built-in option for a matrix arrangement.
With this arrangement, an interrupt is only generated when
two channels are activated simultaneously. The configuration
suppresses additional channel outputs when two channels are
already active.
Both capacitive sensor circuits make it straightforward
to implement a touch display and to add significant
improvements to the user interface. A passive display can be
integrated with touch capabilities in three ways:
(1) add-on integration, where touch pads reside on an extra
touch foil or glass, (2) on-cell integration, where touch pads are
deposited in a separate layer between the front glass and the
top polarizer, and (3) in-cell integration, where touch pads are
placed on the same layer as the display segments, surrounding
the segment electrodes.
V
DD
R
F
R
C
C
F
opt. RC
opt. RC
opt. RC
opt. RC
R
PU
IN[0]
IN[1]
IN[2]
IN[3]
IN[7]
V
DD
V
DD(INTREGD)
100 nF
100 nF
TEST
V
SS
100 nF
C
CPC[0]
CPC[0] CPC[7]
SCL
SDA
CLK_IN
INT_IN
CLK_OUT
INT
A0
SLEEP
PCF8885
R
PU
V
DD
100 nF
C
CPC[7]
to MCU
to MCU
013aaa554
(1)
PCF8885TS application with 16 touch keys
Demo board OM11058 for climate-control application with
touch foil on TFT display
Demo boards OM11057 and OM11057A for multiplexed
and direct-touch applications
Evaluation board OM11056 with two PCF8885TS switches
enabling 64 touch sensors
Touch control on a passive LCD, with touch sensors
integrated into LCD cells
Type number Channels Touch /proximity pads Package(s) Grade Evaluation and demo board(s)
PCF8885TS 8
28 with one circuit
64 with two cascaded circuits
TSSOP28 Industrial
Evaluation boards OM11056/7/7A
Touch-on-display demo board OM11058
PCA8885TS 8
28 with one circuit
64 with two cascaded circuits
TSSOP28 Automotive AEC-Q100
Evaluation boards OM11057/57A
Touch-on-display demo board OM11058
PCA8886TS 2 2 touch or poximity pads TSSOP16 Automotive AEC-Q100 Evaluation and demo board OM11052
PCF8883T, PCF8883CX8 1 1 touch or poximity pad SO8, WLCSP Industrial Evaluation and demo board OM11055
Selection guide