BU21051FS Datasheet, PDF (4/7 Pages) Rohm – Capacitive Sensor Switch Control IC

BU21051FS
Technical Note
●Pin Description
Pin
No
Name
I/O
Function
Notes
1 DVDD Power Digital part Power supply Digital part Power supply
Supply
referen Reset level^※1
ce
I/O
Pad
-
2 GND Ground Ground
-
-
3 SREF AIn Standard capacitor input
-
AVDD “Hi-Z”
③
4 SIN1 AIn Sensor input1
-
AVDD “Hi-Z”
③
5 N.C.
- No connect
-
-
-
-
6 SIN2 AIn Sensor input 2
-
7
THON
AIn
Sensor ON threshold
voltage input
-
8
THOFF
AIn
Sensor OFF threshold
voltage input
-
9 AVDD Power Analog part Power supply
-
AVDD “Hi-Z”
③
AVDD “Hi-Z”
③
AVDD “Hi-Z”
③
-
10 TST
11 SDN
12 PO2
In Test input
In Shutdown input
Out Switch output 2
Usually tide to “L”
DVDD
-
①
“H” : state of operation
“L” : halt condition
DVDD
①
Sensor pin2 On → “L”, Off → “Hi-Z” DVDD “Hi-Z”
②
13 PO1 Out Switch output 1
Sensor pin1 On → “L”, Off → “Hi-Z” DVDD “Hi-Z”
②
14 FILTER In Filter selection
“H”: Filter effect: strong
“L”: Filter effect: Weak
DVDD
①
15 GAIN[0] In
Gain level selection
16 GAIN[1] In
GAIN[1:0] = 00 : Strong
GAIN[1:0] = 01 :
GAIN[1:0] = 10 :
GAIN[1:0] = 11 : Week
Gain
DVDD
DVDD
①
①
※*1 Initial State ① When internal organs power-on reset is effective
② When SDN = “L”
●I/O Circuit
①CMOS input
②CMOS 3state output
③CMOS 3state output with analog switch
I
PAD
CIN
PAD
AIN
PAD
ASW
OEN
【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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2009.04 - Rev.B