Capacitive Sensor Control IC Series
Capacitive Sensor Switch
Control IC
BU21050FS
●Description
BU21050FS are the capacitive sensor controller with 8ch respectively.
The IC has the port interface and easy to replace the point of switch to this controller.
●Features
1) Port output interface
2) Few software control
3) 4bit Binary outputs or 8GPIO outputs
4) 5V power supply voltage available
5) Integrated 10bit AD converter, clock and reset
6) Package SSOP-A32
●Applications
It is possible to use it widely as a switch such as home electric appliance.
●Absolute
Maximum Ratings (Ta=25℃)
PARAMETER
Applied voltage
Input voltage
Storage temperature range
Power dissipation
SYMBOL
AVDD
DVDD
V
AIN
V
DIN
T
stg
P
d
RATING
MIN
-0.3
-0.3
-0.3
-0.3
-55
760
MAX
7.0
7.0
AVDD + 0.3
DVDD + 0.3
125
No.09048EBT01
UNIT
V
V
℃
mW
Ambient temperature reduces a permission loss by 7.6mW per case more than 25 degrees Celsius, 1 degree Celsius
●Recommended
Operating conditions
PARAMETER
Applied voltage
Operating temperature range
SYMBOL
AVDD
DVDD
T
opr
RATING
MIN
4.5
4.5
-40
TYP
5.0
5.0
25
MAX
5.5
5.5
85
UNIT
V
V
℃
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1/7
2009.04 - Rev.B
BU21050FS
●Electrical
characteristics(Especially, Topr=25℃ and AVDD=DVDD=0 as long as it doesn't specify it.)
Rating
Item
Symbol
Unit
Min
Typ
Max
DC characteristics
Input“H”voltage
Input“L”voltage
Output“H”voltage
Output“L”voltage
Input leakage current
Output leakage current
Standby current
Operation current
V
IHIO
V
ILIO
V
OL
I
IZ
I
OZ
I
ST
I
DD
DVDD x 0.9
GND – 0.2
GND
-1
-
-
-
-
-
-
-
-
-
-
550
DVDD + 0.2
DVDD x 0.1
DVDD
DVDD x 0.2
1
1
2
-
V
V
V
V
μA
μA
μA
uA
Technical Note
Condition
V
OHIO
DVDD x 0.8
I
OH
= -2[mA].Overshoot is excluded.
I
OL
= 2[mA].Undershoot is excluded.
Shutdown (SDN=“L”)
●A/D
Converter
PARAMETER
Resolution
Analog Input voltage
Change clock frequency
Change time
Zero scale voltage
Full scale voltage
Differential non line accurate
Integrate non line accurate
●CR
Oscillator characteristic
RATING
MIN
0.8
TYP
1.6
MAX
2.5
SYMBOL
MIN
-
GND
0.2
-
-
AVDD - 0.07
-
-
RATING
TYP
10
-
-
13
-
-
-
-
MAX
-
AVDD
2.0
-
GND + 0.07
-
±3
±3
UNIT
bit
V
MHz
μsec
V
V
LSB
LSB
Condition
V
AIN
f
adck
f
tim
f
adck
= 1[MHz]
DNL
INL
PARAMETER
Frequency Oscillation
SYMBOL
f
cr
UNIT
MHz
Condition
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2/7
2009.04 - Rev.B
BU21050FS
Technical Note
●Block
Diagram, Pin configuration
PO8
GAIN[1]
GAIN[0]
INSEL
AVDD
TST3
TST2
TST1
TST0
PO2
PO4
PO5
PO1
PO3
PO6
PO7
・Sensor
I/F CV Conversion Circuit
This part selects target sensor and converts its capacitance to a voltage signal. Specifically, all eight sensors are selected
one-by-one and their capacity is compared to a common referencecapacity. Each difference value is converted to a certain
voltage signal.
・AD
Conversion
The voltage signal derived from CV conversion is further converted to digital value by this block.
・Conversion
Sequence Control
This block controls the process of CV conversion and generates timing of selecting target sensors.
・Noise
Filter
The GND level difference between appliance and human body will cause noises to the CVconversion circuit.
This block eliminates these noises.
・Compare
threshold
CV converted to sensor data On / Off compared with a threshold, the switch converts the signal.
・Interface
Selection
By setting this block, output mode can be set to either 8-bit PIO mode or 4-bit binary mode.
・Calibration
When the capacitance change do not exceed the threshold for a certain period, this block
tarts-up calibration process.
・Reset
Generation
This is internal reset circuit. Reset is initialized by external SDN signal.
・Clock
Generation
Clock from internal RC oscillation circuit is used as system clock.
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3/7
2009.04 - Rev.B
FILTER
THON
THOFF
SIN3
GND
SIN1
SIN2
SIN5
SIN6
SDN
DVDD
SIN4
SREF
SIN7
SIN8
IFSEL
BU21050FS
●Pin
Description
Pin
Name
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
SDN
DVDD
GND
SREF
SIN1
SIN2
SIN3
SIN4
SIN5
SIN6
SIN7
SIN8
THON
THOFF
AVDD
FILTER
Technical Note
I/O
In
Function
Shutdown input
Note
“H” : state of operation
“L” halt condition
Digital part Power supply
-
-
-
-
-
-
-
-
-
-
-
Supply
DVDD
-
-
AVDD
AVDD
AVDD
AVDD
AVDD
AVDD
AVDD
AVDD
AVDD
AVDD
AVDD
Reset Level I/O Pad
①
Power Digital part Power supply
Ground Ground
AIn
AIn
AIn
AIn
AIn
AIn
Ain
AIn
AIn
AIn
Standard capacitor input
Sensor input1
Sensor input 2
Sensor input 3
Sensor input 4
Sensor input 5
Sensor input 6
Sensor input 7
Sensor input 8
“Hi-Z”
“Hi-Z”
“Hi-Z”
“Hi-Z”
“Hi-Z”
“Hi-Z”
“Hi-Z”
“Hi-Z”
“Hi-Z”
“Hi-Z”
“Hi-Z”
③
③
③
③
③
③
③
③
③
③
③
Sensor ON threshold voltage
input
Sensor OFF threshold voltage
AIn
input
Power Analog part Power supply
In
Filter selection
-
“H”: Filter effect: strong
“L”: Filter effect: Weak
“H” :ON : L-Active,
OFF : Nch Open Drain
“L”: 4bit Binary Mode
H-Active, L
“H” : simultaneous push
banned
“L” : 8 outputs setting
GAIN[1:0] = 00 : Strong
GAIN[1:0] = 01 :
Gain
GAIN[1:0] = 10 :
GAIN[1:0] = 11 : Week
-
-
-
-
INSEL=“L”: Binary Mode
0000 = Button OFF
0001 = SIN1 ON
1000 = SIN8 ON
Usually tide to “L”
Usually tide to “L”
Usually tide to “L”
Usually tide to “L”
-
DVDD
①
17
IFSEL
In
Sensor output selection
DVDD
①
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
INSEL
GAIN[0]
GAIN[1]
PO8
PO7
PO6
PO5
PO4
PO3
PO2
PO1
TST0
TST1
TST2
TST3
In
In
In
Out
Out
Out
Out
Out
Out
Out
Out
In
In
In
In
simultaneous push selection
DVDD
DVDD
DVDD
DVDD
DVDD
DVDD
DVDD
DVDD
DVDD
DVDD
DVDD
DVDD
DVDD
DVDD
DVDD
“Hi-Z”
*2
“L”
*3
“Hi-Z”
“Hi-Z”
“Hi-Z”
“Hi-Z”
“Hi-Z”
“Hi-Z”
“Hi-Z”
“L”
“L”
“L”
“L”
“L”
“L”
“L”
①
①
①
②
②
②
②
②
②
②
②
①
①
①
①
Gain level selection
sensor output8
sensor output7
sensor output6
sensor output5
sensor output4/BIN[3]
sensor output3/BIN[2]
sensor output2/BIN[1]
sensor output1/BIN[0]
digital part test input0
digital part test input1
digital part test input2
digital part test input3
①When
internal organs power-on reset is effective
②When
SDN=”L”
※2
“Hi-Z” when PIO Mode
※3
“L” when Binary Mode
※*1
Initial State
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4/7
2009.04 - Rev.B
BU21050FS
●I/O
Circuit
①CMOS
INPUT
②CMOS
3state output
Technical Note
③CMOS
3state output with analog switch
I
PAD
AIN
ASW
PAD
CIN
PAD
OEN
【IFSEL:
Output interface format】
IFSEL
H
L
INSEL = H : 8GPIOs output mode
Initial status PO[8:1] = Hi-Z
INSEL = L : 4bit Binary output mode
Initial Status PO[4:1] = L
Button
PO[4:1]
Button OFF
0000
SIN1
0001
SIN2
0010
SIN3
0011
SIN4
0100
SIN5
0101
SIN6
0110
SIN7
0111
SIN8
1000
Only the first sensor input was effective in terms of button ON judgment when more than one input has occurred.
Next judgment would be done after all the button is OFF.
【INSEL
: Simultaneous push judgment control】
This setting is effective when IFSEL = “H”
INSEL
Function
H
L
Simultaneous push banned
Simultaneous push effective
Mode
8ch PIO
4bit Binary
Output format
L-active, Nch Open Drain
H-active, L
Note
Only the dominant button will outputwhen more than 2 buttons were pressed
Every button that was pressed will output
【THON:
Button OFF→ON threshold value judge】
【THOFF:
Button ON→OFF threshold value judge】
Setting the threshold value of electrostatic Sensor Switches. By applying voltages can be set.
As an example, 1/2VDD applied to the entire range of the sensor output 1 / 2 to set the threshold value.
In fact, the voltage setting resistance to the partial pressure is recommended to us.
【GAIN
Selection】
Sensor gain can be set in 4 stages
GAIN[1:0] = 00 (x92)
GAIN[1:0] = 01 (x69)
GAIN[1:0] = 10 (x46)
GAIN[1:0] = 11 (x1)
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© 2009 ROHM Co., Ltd. All rights reserved.
5/7
2009.04 - Rev.B
