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Featured Products
Easy to mount • Supports long wiring distances
Capacitive Switch Controllers
BU21072MUV/BU21078MUV/BU21077MUV/BU21079F
Compatible with large
appliances
Cop
Scan
Supports long wiring
distances
y
Durable • Stain-resistant
−
Can be used on thick and/or
curved surfaces, increasing
design flexibility
Menu
+
Class-Leading Noise Immunity (IEC61000-4-6 Compliant)
● High noise immunity
● No EMI countermeasures results in fewer parts required
ROHM utilizes a proprietary high-sensitivity detection AFE for high noise
immunity. As a result, ROHM’s capacitive switches were able to clear the
difficult IEC61000-4-6 standard for noise testing.
Simple
Operation
Small
Mounting
Area
Low
Power
Consumption
Reduced
Standby
Power
Conventional
ROHM
±3V
±10V
±10V GND
noise immunity
Overlay Thickness (mm)
Compressor
Noise
Support for wiring distances over 1m ensure compatibility
with large appliances
Overlay Thickness (Acrylic Board)
Conventional
ROHM
10mm
15mm
High noise immunity makes it possible to separate the IC from the
electrodes across much greater distances than conventional products,
providing greater design flexibility.
Electrode Wiring Length
Conventional
30 to 50cm
Parasitic capacitance: 7.1pF
6
7
5cm
5cm
High
Sensitivity
10mm
1m
Sensor
Electrodes
15mm
ROHM
1m+
ROHM survey
ROHM survey
3
5
Electrode Size (mm 2)
GND
Unmatched wiring distance compatibility
Operating Area
4
Noise
countermeasure
required
Normally, in order to minimize the effects of noise from the AC line,
compressor, or other source, noise suppression components are required.
However, the BU2107x series features high noise immunity, eliminating the
need for noise countermeasures, simplifying design while reducing costs
significantly.
Inoperable Area
3
Compressor
Power Supply
AC Plug
High-speed sampling
and analog circuitry
12
0
AC Noise
ROHM survey
Electrode Size vs. Overlay Thickness
6
Noise countermeasure
required
Touch Panel
Compatible even with 15mm acrylic overlays
9
Ex: AC
Noise Immunity
Best-In-Class Sensitivity
15
Specialized internal circuitry reduces the number of parts required
for EMI countermeasures.
IC
Capacitive Touch
Controller IC
Block Diagram
VDD
(Sensor)
AVDD
LDO28
VREF
: 10ch
BU21078
: 12ch
BU21077,79 : 8ch
LDO15
Supports direct
connection to
Li-ion batteries
BU21072
DVDD
POR
OSC
LOGIC
Touch
AEF_CNT
A/D
PROM
No EMI
countermeasure
required
TEST
Electrode
(PCB)
AFE
WRAM
SDA
SCL
C/V
Converter
WDTR
MPU
HOST
I/F
SIN0-9
Sensor
AFE
LED0-5
DTG
LEDDRV
PWM_CNT
INT
VSS
(LED)
BU21072
: 6ch
BU21078
: 8ch
BU21077,79 : ---
Application Examples
Capacitive Touch Switches
Capacitive Touchscreens
High-speed sensing technology utilized for high noise
immunity touch switch operation
Our touchscreen controllers utilize an original
mutual-type, single-layer multi-touch AFE* for high noise
immunity
*AFE (Analog Front End)
Menu
User Interface Control Technology
(Cultivated through years of user interface development)
Successive
Approximation
A/D Converter
PC Interface
Noise-cancelling
technology through
high S/N ratio
High-accuracy high noise-cancelling
technology based on over a decade
of development experience
High-sensitivity
detection
circuitry
Resistive Touchscreens
We offer a broad lineup compatible with
resistive touchscreens of all types, including
single, dual, automotive-grade,
and systems not equipped with an
MCU.
Capacitive Switch Controller Lineup
Part No.
Supply
Voltage (V)
No. of
Channels
LED
Drive CH
LED PWM
Control
Matrix
Control
Interface
Package
BU21072MUV
3.0 to 3.6
10
6
○
4×4
I 2C
VQFN024V4040
BU21078MUV
3.0 to 3.6
12
8
○
6×6
I 2C
VQFN028V5050
BU21077MUV
3.0 to 5.5
8
-
-
8ch (flexible
combination)
I 2C
VQFN020V4040
BU21079F
3.0 to 5.5
8
-
-
4×4
I 2C
SOP16
The content specified in this document is correct as of October 1st, 2013.
[O_024] Catalog No.56O6715E 10.2013 ROHM © PDF
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