ROHM BU21009MUV Technical data

Capacitive Sensor Control IC Series

Capacitive Sensor Switch
Control IC

BU21009MUV

●Description

BU21009MUV is the capacitive sensor controller for the switch function and slider function with 16 channels sensors.
All channels are calibrated for the slider functions. So this is useful for 16 switches application, too.
LED driver is available (No PWM function).

●Features

1) Slider function

2) LED driver available

3) 2 wire serial interface

4) Power supply = 2.5V to 3.3V, I/O power supply = 1.7V to 3.3V

5) Integrated 10bit AD converter, clock and reset

6) Package VQFN032V5050

●Applications

It is possible to use it widely as a switch/slider such as a Mobile phone, Portable equipment, and Audiovisual apparatuses.

●Absolute Maximum Ratings (Ta=25℃)

PARAMETER SYMBOL

APPLIED VOLTAGE

INPUT VOLTAGE

STORAGE TEMPERATURE RANGE Tstg -55 125 ℃

POWER DISSIPATION Pd 304 mW

Ambient temperature reduces a permission loss by 3.1mW per case more than 25 degrees Celsius, 1 degree Celsius.

●Recommended Operating conditions

PARAMETER SYMBOL

APPLIED VOLTAGE

OPERATINGTEMPERATURE RANGE Topr -40 25 85 ℃

AVD D -0. 3 4. 5

DVDD -0.3 4.5

VAIN -0.3 AVDD+0.3

VDIN -0.3 DVDD+0.3

AVDD 2.5 3.0 3.3 V

DVDD 1.7 3.0 3.3 V

MIN MAX

MIN TYP MAX

RATING

RATING

No.09048EBT03

UNIT

V

V

UNIT

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1/13

2009.04 - Rev.B

BU21009MUV

●Electrical characteristics(Especially, Topr=25 ℃ and AVDD=DVDD=0 as long as it doesn't specify it.)

PARAMETER SYMBOL

H INPUT VOLTAGE VIHIO

L INPUT VOLTAGE VILIO

Output "H" voltage VOHIO

OLLED

V

Output "L" voltage

VOLTXD

VOLINT

Input leakage current IIZ

MIN TYP MAX

DVDDx0.8 - DVDD+0.3 V

DVSS-0.3

DVDD-0.7

AVSS

DVSS

DVSS

-1

RATING

-

-

-

-

-

-

UNIT Condition

DVDDx0.2 V

DVDD V

0.5

0.5

DVDDx0.3

0.5

IOH=-2[mA]. Overshoot is excluded.

IOL=8[mA]. Undershoot is excluded. LED output.
I

OL=3[mA]. Undershoot is

excluded. SDA/TXD

V

application.

OL=2[mA]. Undershoot is excluded. INT

I
application.

1 μA

Technical Note

DVDD > 2[V]

DVDD ≦ 2[V]

Off leakage current IOZ

Standby current IST

Current of operation IDD

-1

-

- - 2 μA

- 300 - μA

1 μA

Shutdown (SDN＝”L”)

●A/D Converter

PARAMETER SYMBOL

MIN TYP MAX

RATING

UNIT Condition

Resolution - 10 - bit

Analog Input voltage VAIN AVSS - AVDD V
change clock frequency fadck 0.2 - 2.0 MHz
change time ftim - 77 - μsec fadck = 1[MHz]
Zero scale voltage - - AVSS+0.07 V
full scale voltage AVDD-0.07 - - V
differential Non line accurate DNL - - ±3 LSB
Integrate Non line accurate INL - - ±3 LSB

●CR Oscillator characteristic

PARAMETER SYMBOL

Frequency Oscillation

f

cr 0.4 1.1 2.0

MIN TYP MAX

RATING

UNIT Condition

MHz

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2/13

2009.04 - Rev.B

BU21009MUV

●Block Diagram, Pin configuration

AVDD DVDD

Technical Note

SDA/TXD

CLK_EXT

SCL

RXD

SDN

CS

TSTD

INT

SREF

SIN[15:0]

CS

SCL

SDA/TXD

RXD

SDN

CLK_EXT

Sensor I/F、
CV translate
circuit

Reset

generation

Power
on
Reset

Conversion

sequence control

Clock

generation

CR
oscill
ation

AVSS

ADC

Data correction and

making to format

Data register

host I/F

DVSS

Power

management

INT

MODE[1:0]

DVSS

DVDD

AVDD

SREF

SIN[0]

SIN[1]/LED[0]

SIN[2]

SIN[3]/LED[1]

MODE[1]

MODE[0]

AVSS

TSTA

SIN[15]/LED[7]

SIN[4]

SIN[13]/LED[6]

SIN[13]/LED[6]

SIN[12]

SIN[11]/LED[5]

SIN[10]

SIN[9]/LED[4]

SIN[8]

SIN[7]/LED[3]

SIN[6]

SIN[13]/LED[6]

SIN[4]

SIN[5]/LED[2]

・Sensor I/F CV translate circuit

This module selects between sensor inputs. The selection sequences between all 16 channels.

・AD Conversion

The voltage into which CV is converted is converted into a digital value.
Conversion is 10 bit and full scale corresponds to AVDD.

・Conversion sequence control

Performs timing generation for the analogue circuitry and a sequencer circuit for selection of the sensor channel for conversion.

・Data correction and making to format

This module provides the digital intelligence of the sensor.
The block includes, amongst other things, scaling, adding offsets and input filtering for de-bouncing.
Registers are formatted to simplify usage by the softwareapplication.
The block implements auto-calibration to manage drift in temperature, process variation, voltage variation and aging effects.

・Data register

This stores the results for the software application. Please refer to the register map for details.

・HOST I/F

2 wire serial interface.

・Power management

The power management block provides smart power control.
When the sensors are not in use, the Controller automatically transitions into a low-power mode.
When a sensor is touched, then the device automatically wakes up and enters its normal operation.
The chip drives an INT pin for alerting the controller device in this case.

・Reset generation

The circuit is initialized by a either a soft reset command or by the external SDN pin.

・Clock generation

The device has an internal oscillator.
Provision is also made if the application would like to make use of an external clock input.

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3/13

2009.04 - Rev.B

BU21009MUV

●Pin Description

Pin
No.

1 SIN4 AIn sensor input4 - AVDD "Hi-Z" ④

2 SIN5/LED2 AIn/Out

3 SIN6 AIn sensor input6 - AVDD "Hi-Z" ④

4 SIN7/LED3 AIn/Out

5 SIN8 AIn sensor input8 - AVDD "Hi-Z" ④

6 SIN9/LED4 AIn/Out

7 SIN10 AIn sensor input10 - AVDD "Hi-Z" ④

8 SIN11/LED5 AIn/Out

9 SIN12 AIn sensor input12 - AVDD "Hi-Z" ④

10

11 SIN14 AIn sensor input14 - AVDD "Hi-Z" ④

12

13 TSTA AIn Test input for analog block

14 AVSS Ground Analog ground - - - -

Name I/O Function Note

SIN13/LED

6

SIN15/LED

7

AIn/Out

AIn/Out

sensor input 5
/PW Drive LEDcontrol output 2

sensor input 7
/PWM Drive LED control output 3

sensor input 9
/LED control output 4

sensor input 11
/LED control output 5

sensor input 13
/LED control output 6

sensor input 15
/LED control output 7

sensor input ,
LED drive select

sensor input ,
LED drive select

sensor input ,
LED drive select

sensor input ,
LED drive select

sensor input ,
LED drive select

sensor input ,
LED drive select
NC on the substrate is
recommended.

Supply

Reference

AVDD "Hi-Z" ④

AVDD "Hi-Z" ④

AVDD "Hi-Z" ④

AVDD "Hi-Z" ④

AVDD "Hi-Z" ④

AVDD "Hi-Z" ④

AVDD "Hi-Z" ④

Technical Note

Reset

Level

I/O Pad

15 MODE[0] In Mode selection, input0

16 MODE[1] In Mode selection, input1 DVDD - ①

17 TSTD In Digital part test input Usually must be tide to "L" DVDD - ①

18 CLK_EXT In External system clock input Usually tide to"L" DVDD - ①

19 INT Out Output of interrupt

20 SDA/TXD In/Out

21 SCL In

22 RXD In

23 CS In

24 SDN In Shutdown input

25 DVSS Ground Digital part ground - - - -

26 DVDD Power Digital part Power supply - - - -

27 AVDD Power Analog part Power supply - - - ④

28 SREF AIn Standard capacitor input - AVDD "Hi-Z" ④

Communication data sending and
receiving(2wires serial)

Communication
synchronous clock input
system clock input
(2wires serial)
Slave address selection
(2wires serial mode)

00 = 2wires serial,
internal clock

"L" : Active mode
"H" : Idle mode ※2

- DVDD

- DVDD - ②

"L" : Internal clock
"H" : external clock
"L" : 5Ah
"H" : 5Bh
"L" : Halt condition
"H" : state of operation

DVDD - ①

DVDD "L" ③

"Hi-Z"

-

DVDD - ②

DVDD - ②

DVDD - -

⑤
②

29 SIN0 AIn sensor input 0 - AVDD "Hi-Z" ④

30 SIN1/LED0 AIn/Out

31 SIN2 AIn sensor input 2 - AVDD "Hi-Z" ④

32 SIN3/LED1 AIn/Out

*1 Initial State When internal organs power-on reset is effective
Halt condition SDN=”L”

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sensor input 1
/PWM Drive LEDcontrol output 0

sensor input 3
/PWM Drive LEDcontrol output 1

sensor input ,
LED drive select

sensor input ,
LED drive select

4/13

AVDD "Hi-Z" ④

AVDD "Hi-Z" ④

2009.04 - Rev.B

BU21009MUV

●I/O Circuit

①CMOS INPUT ②CMOS Schmitt INPUT ③CMOS OUTPUT

Technical Note

CIN

④CMOS 3stute OUTPUT

with ANALOG-SW

PAD

⑤CMOS Schmitt INOUT

ASW

AIN

PADI

OE

CIN

PADI

OEN

PADCIN

I

PAD

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2009.04 - Rev.B

BU21009MUV

Technical Note

●HOST I/F
・ 2 wire serial, BUS (Pin configuration, MODE［1:0］＝00b)

Slave mode only
Slave Address = 5Ch,5Dh selection possible.
Normal (Normal mode. 100kHz Transfer rate)
Fs mode (Fast mode. 400kHz Transfer rate) also.
Not adapting sequential read / write.

【Data format】

t

HD;STA

t

SU;STO

SDA

t

SU;DAT

t

HD;DAT

SCL

Address

Read

ACK

Data Data

ACK

ACK

Parameter Standard mode High Speed mode Unit

MIN MAX MIN MAX
fSCL : SCL Clock Freq 0 100 0 400 kHz
t

: START condition hold time 4.0 - 0.6 - μsec

HD;STA

t

: SCL “L” 4.7 - 1.3 - μsec

LOW

t

: SCL “H” 4.0 - 0.6 - μsec

HIGH

t

: Data hold time 0.1 3.45 0.1 0.9 μsec

HD;DAT

t

: Data setup time 0.25 - 0.1 - μsec

SU;DAT

t

: START condition hold time 4.0 - 0.6 - μsec

SU;STO

t

: Free time of bus between STOP condition and START condition 4.7 - 1.3 - μsec

BUF

【PROTOCOL】

・Write Protocol

S SLAVE ADDRESS W

7bit = 5Ch or 5Dh 8bit 8bit

A

REGISTER

ADDRESS

A WRITE DATA AP

・Read Protocol

S SLAVE ADDRESS W

7bit = 5Ch or 5Dh 8bit 7bit = 5Ch or 5Dh 8bit

A

REGISTER

ADDRESS

A S SLAVE ADDRESS R A READ DATA N P

from Master to Slave S = START condition

from Slave to Master P = STOP condition

R = data direction READ (SDA HIGH)

W = data direction WRITE (SDA LOW)

A = acknowledge (SDA LOW)

N = not acknowledge (SDA HIGH)

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2009.04 - Rev.B

BU21009MUV

●Register map

Address Register name R/W Length Explanation

1*h SENS_DATA R 1byte / channel Sensor output data. One for each channel.

30h POSX R 1byte X positional value axially.

31h POSY R 1byte Y positional value axially.

32h, 33h BTN R 2byte Button On/Off.

4*h OFFSET R 1byte / channel Offset correction data. One for each channel.

ECh POS_MODE W 1byte XY matrix setting.

EDh RESET W 1byte Soft reset execution.

EEh CALIB W 1byte Soft calibration execution.

EFh DONE W 1byte Setting done command.

Technical Note

F0h, F1h SENS_CH W 2byte Sensor channel enables.

F2h LED_CH W 1byte LED channel enables.

F3h, F4h IDLE_CH W 2byte Idle mode release control.

F5h LED_LINK W 1byte LED linkage to sensor input.

F6h TIMES W 1byte

F7h TH_ON2 W 1byte

F8h, F9h TH_ON2_CH W 2byte Per channel selection of whether to use TH_ON or TH_ON2.

FAh CMD W 1byte Simultaneous press and idle mode entry.

FBh GAIN_FILTER W 1byte Gain setting, filter function.

FCh TH_ON W 1byte

FDh TH_OFF W 1byte

FEh DLED W 1byte Register to allow simple writing to LEDs.

Defines the sampling interval and number of samples
required to recognize a button press.

A second threshold value in the detection of a button going
from OFF state to ON state.

A threshold value in the detection of a button going from OFF
state to ON state.

A threshold value in the detection of a button going from ON
state to OFF state.

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BU21009MUV

【1*h : Sensor Output Data】

Name: SENS_DATA
Address: 1* h (one byte per sensor channel)
Description: The sensor output that converts to 10bit. Scaling, offsets and filtering (when enabled) are applied.
The most significant 8 bits are presented to the software with this register.

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

1*h SD_*[7] SD_*[6] SD_*[5] SD_*[4] SD_*[3] SD_*[2] SD_*[1] SD_*[0]

R/W R R R R R R R R

Initial val. 1 0 0 0 0 0 0 0

【30h : X positional value axially】

Name: POSX
Address: 30h
Description: This represents the X-position of the press. The value is calculated differently depending on the matrix
arrangement. For example when:

・When POS_MODE[0]=0： Value interprets SIN[0:7]
・When POS_MODE[0]=1： Value interprets SIN[10:5]

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

30h 0 0 D5 D4 D3 D2 D1 D0

R/W R R R R R R R R

【31h : Y positional value axially】

Name: POSY
Address: 31h
Description: This represents the Y-position of the press. The value is calculated differently depending on the matrix
arrangement. For example when:

・When POS_MODE[0]=0： Value interprets SIN[8:15]

・When POS_MODE[0]=1： Value interprets SIN[11:4:12:3:13:2:14:1:15:0]

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

31h 0 D6 D5 D4 D3 D2 D1 D0

R/W R R R R R R R R

【32h / 33h : Button ON/OFF】

Name: BTN
Address: 32h, 33h
Description: This is the state of the sensor when considered as an ON/OFF button. Here 1 : On. 0 :Off.

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
32h CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH0
33h CH15 CH14 CH13 CH12 CH11 CH10 CH9 CH8

R/W R R R R R R R R

Initial val. 0 0 0 0 0 0 0 0

【4* h : Offset Correction Data】

Name: OFFSET
Address: 4* h (one byte per sensor channel)
Description: This is the offset required to correct the sense data to half scale during the calibration procedure.

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

4*h OFS_*[7] OFS_*[6] OFS_*[5] OFS_*[4] OFS_*[3] OFS_*[2] OFS_*[1] OFS_*[0]

R/W R R R R R R R R

Initial val. 1 0 0 0 0 0 0 0

Technical Note

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2009.04 - Rev.B

BU21009MUV

【ECh : XY matrix setting】

Name: POS_MODE
Address: ECh
Description: Setting when two or more sensor are displayed to the first origin and position is detected.
XY : This selects between two matrix configurations.

1 = X axis →SIN [10 : 5] , Y axis → SIN [11:4:12:3:13:2:14:1:15:0]
0 = X axis →SIN [0 : 7] , Y axis → SIN [8:15]

POS_EN : The position tracking enable

Enables the condition under which the position tracking is made effective.
1=When either of sensor exceeds the threshold, the data of the position tracking is made effective.
If all registers do not exceed the threshold, the data of the position tracking is (POSX,POSY) = (0,0).
0=the position is detected regardless of the level of the sensor data, and data is made effective.

Initial state: When either of sensor exceeds the threshold, the positional detection data is made effective (=1).

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
ECh - - - - - - POS_EN XY
R/W - - - - - - W W

Initial val. - - - - - - 1 1

【EEh : Soft Calibration】

Name: CALIB
Address: EEh
Description: This forces a chip re-calibration when a 1 is written and returns to 0 afterward automatically. Please note
that one should always re-calibrate after changing the gain adjustment value.

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
EEh - - - - - - - CALIB
R/W - - - - - - - W

Initial val. - - - - - - - 0

【EFh : Setting Done, Detect Start】

Name: DONE
Address: EFh
Description: This register should be written to following register updates.

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
EFh - - - - - - - DONE
R/W - - - - - - - W

Initial val. - - - - - - - 0

【F0h / F1h : Sensor Channel Setting】

Name: SENS_CH
Address: F0h / F1h
Description: Individual enabling and disabling of sensor channels. 1：Effective 0：Not in use

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

F0h SIN7 SIN6 SIN5 SIN4 SIN3 SIN2 SIN1 SIN0
F1h SIN15 SIN14 SIN13 SIN12 SIN11 SIN10 SIN9 SIN8

R/W W W W W W W W W

Initial val. 0 0 0 0 0 0 0 0

【F2h : LED Channel Setting】

Name: LED_CH
Address: F2h
Description: Enables and disables the channels to be used as LED outputs. Valid for the 8 LED outputs.
1：Effective 0：Not in use

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

F2h LED7 LED6 LED5 LED4 LED3 LED2 LED1 LED0

R/W W W W W W W W W

Initial val. 0 0 0 0 0 0 0 0

Technical Note

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2009.04 - Rev.B

BU21009MUV

【F3h / F4h : Idle Exit Condition】

Name: IDLE_CH
Address: F3h / F4h
Description: Defines which channels cause the device to wake up – i.e.
go from idle mode to normal operation on a key press. Selection is made on a per channel basis.
1：Effective 0：Not used

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

F3h SIN7 SIN6 SIN5 SIN4 SIN3 SIN2 SIN1 SIN0
F4h SIN15 SIN14 SIN13 SIN12 SIN11 SIN10 SIN9 SIN8

R/W W W W W W W W W

Initial val. 1 1 1 1 1 1 1 1

【F5h : LED to Sensor Linkage】

Name: LED_LINK
Address: F5h
Description: Allows the LED outputs to be automatically linked to the input channels without need for any software control.
1 : It synchronizes with the button. 0 : It synchronizes with data (The register name: DLED) from host.

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

F5h LED7 LED6 LED5 LED4 LED3 LED2 LED1 LED0

R/W W W W W W W W W

Initial val. 1 1 1 1 1 1 1 1

【F6h : Sampling Interval】

Name: TIMES
Address: F6h
Description: Defines the sampling interval.

SAMP[1:0] : Sampling Interval ：

Given by the following equation :
Sampling interval = system clock x 2

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

F6h - - - - - - SAMP[1] SAMP[0]

R/W - - - - - - W W

Initial val. - - - - - - 0 0

【F7h : Button OFF→ON Threshold】

Name: TH_ON2
Address: F7h
Description: A second threshold value for determining a button off→on judgment of sensor.
The sensor output value of 8bit (register SENS_DATA) is compared with 128+ ON2 [6:0],
and if it is larger, the button is determined active.

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

F7h - ON2[6] ON2[5] ON2[4] ON2[3] ON2[2] ON2[1] ON2[0]

R/W - W W W W W W W

Initial val. - 0 0 1 0 0 0 0

【F8h / F9h : Button OFF→ON Threshold Selection】

Name: TH_ON2_CH
Address: F8h / F9h
Description: This register is used to relate either threshold TH_ON or TH_ON2 to particular sensor channels
for button press activity determination.
1 : TH_ON2 is applied 0 :TH_ON is applied

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

F8h SIN7 SIN6 SIN5 SIN4 SIN3 SIN2 SIN1 SIN0
F9h SIN15 SIN14 SIN13 SIN12 SIN11 SIN10 SIN9 SIN8

R/W W W W W W W W W

Initial val. 0 0 0 0 0 0 0 0

13

x SAMP (Example: system clock 1[MHz] time : About 8.2[msec]).

Technical Note

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2009.04 - Rev.B

BU21009MUV

【FAh : Simultaneous Press and Idle Mode Entry】

Name: CMD
Address: FAh
Description:

INTERMIT_EN : Intermittent and the drive are enable. ：

Whether intermittent is driven at the idol mode is selected.

1：Intermittent is driven. 0：Intermittent is not driven. Initial state：Intermittent is driven.

IDLE_T[3:0] : non-detect time-out setting ：

This sets the time the chip takes to go from normal mode to idle mode in a period key inactivity.
Duration = system clock x 2

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0

FAh - - - INTERMIT_EN IDLE_T[3] IDLE_T[2] IDLE_T[1] IDLE_T[0]

R/W - - - W W W W W

Initial val. - - - 1 0 1 1 1

【FBh : Gain Setting, Filter Function】

Name: GAIN_FILTER
Address: FBh
Description: Gain adjustment and setting of noise filter function.

GAIN[2:0] : gain setting：

It uses it for the gain adjustment in eight stages. Initial adjustment value：x1

GAIN[2:0] 000 001 010 011 100 101 110 111

Adjustment value x 1 x 4.22 x 8.4 x 16.5 x 23 x 46 x 69 x 92

FILTER_EN : Filter enable ：

Enables/disables setting of noise filter function
1 : enabled 0 : disabled Initial state : disabled

DELTA[3:0] : Filter follow count setting ：

The follow count to which the noise filter function is effective is set.

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
FBh GAIN[2] GAIN [1] GAIN[0] FILTER_EN DELTA[3] DELTA[2] DELTA[1] DELTA[0]
R/W W W W W W W W W

Initial val. 0 0 0 0 0 0 1 0

【FCh : Switch OFF -> ON Threshold】

Name: TH_ON
Address: FCh
Description: This register provides a threshold value for determining if a sensor has transitioned from OFF to ON.
This is relative value from reference value (128d). So the absolute value of threshold is 128d + ON[6:0].
It makes a threshold value between TH_ON and TH_OFF.
TH_ON must be bigger than TH_OFF (TH_ON >= TH_OFF)
Maximum threshold is 256d and minimum value is 128d.

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
FCh - ON[6] ON[5] ON[4] ON[3] ON[2] ON[1] ON[0]
R/W - W W W W W W W

Initial val. - 0 0 1 0 0 0 0

19

x IDLE_T (Example of system clock 1[MHz]time : About 520[msec])

Technical Note

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2009.04 - Rev.B

BU21009MUV

Technical Note

【FDh : Switch ON -> OFF Threshold Value】

Name: TH_OFF
Address: FDh
Description: This register provides a threshold value for transitioning from ON to OFF.
This is relative value from reference value (128d). So absolute value of threshold is128d + OFF[6:0].
It makes a threshold value between TH_ON and TH_OFF.
TH_OFF must be smaller than TH_ON (TH_OFF =< TH_ON)
Maximum value is 256d and minimum value is 128d.

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
FDh - OFF[6] OFF[5] OFF[4] OFF[3] OFF[2] OFF[1] OFF[0]
R/W - W W W W W W W

Initial val. - 0 0 0 0 0 0 1

【FEh : LED Port Data】

Name: DLED
Address: FEh
Description: When LED is not linked with the sensor, it becomes a simple digital output that controls the LED.
1 : Light. 0 : Turned off.

Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
FEh D7 D6 D5 D4 D3 D2 D1 D0
R/W W W W W W W W W

Initial val. 0 0 0 0 0 0 0 0

●Operation mode

This IC has a normal mode, idle mode and a shutdown mode as states of operation.

【Normal mode】

This is the normal operation of the device. Output pin INT="L".

【Idle mode】

This is the mode when the normal mode times out due to inactivity on the keys. In this mode the control interface is still
alive.

*Usually time-out is aimed at about 200msec or less.
*Transition between normal and idle modes is automatic and without software control.

【Shutdown mode】

In this mode the device is completely stopped – and reset. This is achieved by making the terminal SDN L. All analog
circuits and the logic circuits are stopped. The return from the shutdown mode returns by making the terminal SDN H.

*After shut-down all registers have their default values.

●Interface and system clock selection

I/F selection with MODE [1:0] pin. System clock selection by RXD.

【Using 2wires serial bus mode (MODE［1:0］＝00b)】

The 2wires serial bus is used for host I/F.
RXD=0 in the system clock: Built-in oscillator is used.
RXD=1 in the system clock: The clock input from CLK_EXT is used.

●Initialization procedure

A normal power on sequence is:

(1) Power on
(2) Setup the registers
(3) Write ‘1’ to 0xEF (done register)

<sensing operation begins after auto-calibration occurs>

●Power supply turning on procedure

You should always power on DVDD at the same time as AVDD or before AVDD.

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12/13

2009.04 - Rev.B

BU21009MUV

●Ordering part number

B U 2 1 0 0 9 M U V - E 2

Technical Note

Part No Part No Package

VQFN032V5050

<Tape and Reel information>

Quantity

Direction
of feed

1.0MAX

0.08 S

0.4± 0.1

0.75

5.0± 0.1

C0.2

5.0± 0.1

1PIN MARK

3.4± 0.1

81

32

25

9

16

24

17

0.25

0.5

+0.03

0.02

+0.05

-

0.04

0.02

-

3.4± 0.1

S

(0.22)

(Unit : mm)

Packaging and forming specification

MUV : VQFN032V5050

Embossed carrier tapeTape
2500pcs

E2

The direction is the 1pin of product is at the upper left when you hold

()

reel on the left hand and you pull out the tape on the right hand

Reel

1pin

Order quantity needs to be multiple of the minimum quantity.

∗

E2：Embossed tape and reel

Direction of feed

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13/13

2009.04 - Rev.B

Notes

No copying or reproduction of this document, in part or in whole, is permitted without the
consent of ROHM Co.,Ltd.

The content specied herein is subject to change for improvement without notice.

The content specied herein is for the purpose of introducing ROHM's products (hereinafter
"Products"). If you wish to use any such Product, please be sure to refer to the specications,
which can be obtained from ROHM upon request.

Examples of application circuits, circuit constants and any other information contained herein
illustrate the standard usage and operations of the Products. The peripheral conditions must
be taken into account when designing circuits for mass production.

Great care was taken in ensuring the accuracy of the information specied in this document.
However, should you incur any damage arising from any inaccuracy or misprint of such
information, ROHM shall bear no responsibility for such damage.

The technical information specied herein is intended only to show the typical functions of and
examples of application circuits for the Products. ROHM does not grant you, explicitly or
implicitly, any license to use or exercise intellectual property or other rights held by ROHM and
other par ties. ROHM shall bear no responsibility whatsoever for any dispute arising from the
use of such technical information.

Notice

The Products specied in this document are intended to be used with general-use electronic
equipment or devices (such as audio visual equipment, ofce-automation equipment, commu­nication devices, electronic appliances and amusement devices).

The Products specied in this document are not designed to be radiation tolerant.

While ROHM always makes efforts to enhance the quality and reliability of its Products, a
Product may fail or malfunction for a variety of reasons.

Please be sure to implement in your equipment using the Products safety measures to guard
against the possibility of physical injury, re or any other damage caused in the event of the
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The Products are not designed or manufactured to be used with any equipment, device or
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may result in a direct threat to human life or create a risk of human injury (such as a medical
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More detail product informations and catalogs are available, please contact us.

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