BU21010MUV-E2

Capacitive Sensor Control IC Series Capacitive Sensor Switch Control IC BU21010MUV No.09048EBY03 ●Note in capacitive sensor board design Here, it explains a recommended value and recommended condition concerning the board, the overlay, and mounting when BU21010MUV of capacitive sensor IC series and the composition by a solid board are assumed. It is not the one to do the operation guarantee though a recommended value and recommended condition are made based on the result of the real machine experiment by an experimental board. On the other hand, it is not the one to fix immovable when not satisfying it either. It treats as a reference of an initial examination, and finally, please experiment the principle by the use of a real machine, and judge the quality of the system by the mounting experiment. ・Board Item Board material Material Numerical value FR4(glass epoxy) thickness ＝1.6mm or more Electrode material Other condition 2 layer both sides structure Cu thickness ＝10um-50um - Electrode size - 36mm over ～ finger contact area twice or less - Electrode form - - Shape doesn't influence sensitivity Wiring width Cu 0.2ｍｍor less The minimum value of the design rule of the board is applied Wiring length Cu 100mm or less - Via size Cu 0.4mm or less The minimum value of the design rule of the board is applied 1) About the size of the sensor electrode ①The area of the sensor must do Hi and become twice or more the gross area of wiring. ②Please give the twice the contact side product of the assumed finger to the upper bound of the area of the sensor as a standard. 2 ③Please give 36mm to the lower bound of the area of the sensor as a standard. 2) About the form of the sensor electrode ①The shape of the sensor doesn't have a big influence in the sensitivity of the sensor. Given the shape of the finger-like circular and rectangular, and is appropriate. ②The design with the copyright like the registration of a design etc. exists, and note special shape, please. 3) Method of setting up sensor electrode and wiring ①The grand area arrangement around the sensor electrode and the sensor wiring is recommended. Please arrange a grand area in the same to sensor electrode layer, and open the gap between a sensor electrode and grand area by 1.0mm or more (To decrease a parasitic capacitance increase). ②The grand area arrangement in the back of the sensor electrode and wiring is recommended. Please arrange a grand area to cover all opposed the sensor electrodes with another layer on the back side of the sensor electrode. The device that suppresses a parasitic capacitance increase such as grand shape being made a mesh is necessary following the thickness 1.6mm in the FR4 board. In that case, please consult separately. www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 1/13 2009.04 - Rev.B Application Note BU21010MUV ・Overlay Item Material Numerical value Other condition Overlay material acrylic ・ glass thickness ＝1.3mm or less High dielectric material Decorative material coat nonconductive thickness ＝50um or less The content of a metallic material is noted Decorative material deposition plating low tin and deposition of conductive metal plating thickness ＝50um or less - constant 1) About the overlay material In the resin system, the acrylic fiber is recommended. In the inorganic system, the glass is recommended. The material with a high permittivity is recommended to be used. 2) The decorative metal-coating material on the carbon content and the volume of film and the low resistance, the sensor can cause a loss of sensitivity. If you want to study painting, paint containing a conductive material and content of the confirmation of whether the content of the variations (on mass) of the sample prepared please check acceptance. 3) By metal-plated decorative materials for the deposition ①It is possible to make the sensor react by depositing the material of low conductive as tin in discontinuity. When a metallic deposition is examined, I hope a panel manufacturer and prior meeting. ②Will be decorating for the electrode surface, touch sensors at the bottom of a multi-electrode reaction at the same time a situation occurs. Specifications for the film by evaporation the degree of impact varies, but as a fundamental measure, the decorative film without a solid arrangement, the top surface of the sensor in the outer groove established electrical, adjacent to the separation of electrical sensors to each other to make a film that is recommended. ・Mounting Item Material Numerical value Other condition thickness ＝100um or less Fixed material Double-faced tape 1) About a fixed material ①Both sides must use the one of the composition that is the base material for the center for specification with the adhesive especially like a no bur and the double-faced tape, etc. for the material, please use 100 um in total thickness following. ②The thickness of the air-gap when bonding is canceled by the calibration function in case of 100um or less. It is possible to correct it even by the one by a change with the lapse of time because it is done at the time of not the setting done to the first stage of manufacturing but each power supply turning on. 2) Sensors on board sensors fixed to the board at the top of double-sided tape at the Ministry of fixed overlay method is recommended. Department back on board, Board recommended conditions (FR4 material, thickness = 1.6mm or more) points if you do not pay attention to the special. If you have a thin or thick board, FPC and stability of shape if not, back to the structural changes in fixed to reduce the parasitic capacitance to charity is required. ●OK NG example of wiring pattern Other signal line Ground line Sensor line www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 2/13 2009.04 - Rev.B Application Note BU21010MUV ●SREF electrode 1) In case SREF (reference electrode) has a same area as sensor electrode. In case SREF electrode is placed on a surface of sensor electrode, it has to be placed with a certain distance from the noise source and the finger contact influence. When it is placed on the back side of the sensor electrode surface, same caution must be taken. Most recommended configuration is to place it into middle layer which are covered by ground area (both front and back side surface). 2) In case capacitor is used. When a capacitor is used as a SREF (reference electrode), please place capacitor in the LSI component side as close as possible. The selection of the capacitance value has to be determined by experiment/tuning. In a commonly used PCB material (no middle connection components such as connectors), under 1 to 10pF is recommended. In conversion theory, because the capacity value near the DC is expected and there is a calibration of the offset cancellation circuit, the capacitor accuracy as well as the temperature characteristics can be satisfied with standard capacitor products. ●Calibration There are 16 sensor ports in BU21010MUV able to use. In the BU21010MUV, Only even ports can calibrate difference of the capacitance between the two sensors to correct. The odd ports will use a result of the even ports that executed calibration. An ideal value of the 8bitADC that the calibration was executed is near to 128. After calibration, the ADC value that first sense is an offset correction data and is kept in register OFFSET (4*h). An offset value will be the difference between the offset correction data and center value 128. The offset value will keep the ADC value center value 128 when the sensor was not touched. Offset value = Offset correction data (4*h) - 128 If the offset correction data is less than 128, it is meaning SREF > SIN. (Gain x1) If the offset correction data is more than 128, it is meaning SREF < SIN. (Gain x1) As for the channel not corrected, the error margin of the offset correction value grows compared with the corrected channel. Because correction value obtained with other channels is misappropriated. Without exceeding the threshold value of turning on not moving at all can happen when this error margin is large. 1) The channel that doesn't do the calibration must be nearer IC than the channel that does the calibration. 2) SREF setting The offset value of SIN1, 3, 5, 7, 9, 11, 13, 15(register address 40h – 4Fh) < 128 Adjust the highest one in SIN1 and SIN3, 5, 7, … SIN15 approach 128 Before calibration C vs. Digitized out Saturated Ideal Smaller sensor (- offset) Bigger sensor (+ offset) Actual out of bigger sensor Plus offset Minus offset www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 3/13 2009.04 - Rev.B Application Note BU21010MUV Reference sensor (SREF) should be adjusted which is balanced to the farthest sensor (SIN1, this example) SREF SIN0 BU21010MUV SIN1 SIN2 SIN3 Red Blue Blue Pair Red Pair Blue: Calibrated channel Red: Non-calibrated channel Non-calibrated channel should be nearer to IC than calibrated channel Example) The switch application of 6ch Use the channel that does the calibration by priority. (SIN0, SIN2, SIN4, SIN6) SIN1, SIN3 wiring: SIN0 > SIN1, SIN2 > SIN3 SIN6 SIN4 SIN3 SREF SIN2 SIN1 SIN0 Equal length VDD SIN5 LED R Not link mode www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 4/13 2009.04 - Rev.B Application Note BU21010MUV ●Appication circuit The following figure illustrated the application circuit of BU21010MUV. 3.0V 1.8V Cdcup 47µF Tantalum capacitor etc... Resisting Voltage 16V over AVDD CIN 0.1µF Ceramic capacitor X5RorX7R over, 1608 over Resisting Voltage16V over DVDD BU21010MUV 1)IC electrostatic times to pull the power to make the layout upstream AVDD please. 2)Control the branching paths after entering the terminal layout to please the most recent. 3)Recommended circuit, the real validation, please always done. ●Application circuit example AVDD 3.0V 0.1uF ・・・ LED Output 3.0V 47uF 0.1uF 47uF AVDD DVDD SREF Sensor Input SIN7 ・・・ ・・・ SIN3 Sensor I/F CV Convertor SIN1 Data Calibration ADC SIN6 ・・・ SIN2 SIN0 SCL Sequence control I2C Data register SDA host I/F SDN Shutdown Input Reset generation Power on Reset Power managment Clock generation CR Oscil lator INT INT Output VSS www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 5/13 2009.04 - Rev.B Application Note BU21010MUV ●Power Supply BU21010 have 2 kinds of power supply pins: DVDD and AVDD. DVDD is the power supply pins used for digital block. AVDD is the power supply pins used for analog block. It is recommended to design PCB with separate analog power supply and digital power supply without common impedance. Moreover, it is recommended to have a countermeasure against noise and ripple at power supply. The bypass capacitor between power supply and ground is essential. A careful study of decoupling capacitor and the line filter on actual PCB. (Please refer to the application circuit diagram example for recommended values). Regarding power supply start-up sequence, it is essential to apply power to DVDD first and then to AVDD or to apply simultaneously power to DVDD and AVDD. If the power is applied to AVDD before DVDD, the initialization may not be guaranteed. When the power has been supplied, the SND signal must be set like following timing. For start-up power supply DVDD, AVDD confirmed the timing of these signals at the launch, please SDN. For standing down power After standing down signal SDN, at the timing of the above DVDD, AVDD started to please lower. ●About IC placement IC will be placed in the environment, humidity and temperature changes locally as a dynamic place for Please avoid easy. Condensation sensors to the terminal, the sensor accuracy may be malfunctioning. ●PCB layout The electrostatic sensor IC, PCB parasitic on the capacity to be vulnerable to the effects of, IC package itself also due to parasitic capacity and can not be ignored completely. In order to minimize the impact on small QFN package is adopted. In addition, the package parasite-induced changes in capacity to hold it back a bit to rand adopted a package. The effect is difficult to present quantitative, the back of the rand dropped to the PCB in order to GND is recommended. www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 6/13 2009.04 - Rev.B Application Note BU21010MUV ●Operating Sequence The following figure illustrated the operating sequence. There are two modes able to use. When use the power management mode, the Host side can monitor INT signal to stop an operation of register read/write. POWER ON Initial Setting Power Management using ? Power Management Mode INT="L" Repeat Block Regiser Read BTN: 0x32h, 33h Gesture: 0x60h,0x61h,0x62h etc.. Regiser Read BTN: 0x32h, 33h Gesture: 0x60h,0x61h,0x62h etc.. Wait Wait Operating sequence flow chart ●Initial Setting The following figure illustrated an initial setting. According as the following flow to set. At the end of setting, to write configuration done “H” and then the detection will start to sense. START 4 Software Reset 5 Senser port Setting 6 LED/PWM Setting 7 Power management Setting 8 Gain/Noise Setting 9 Threshold Setting 10 Gesture Setting 11 Config Done END Initial setting flow chart www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 7/13 2009.04 - Rev.B Application Note BU21010MUV ●Sensor Port Setting To write register F0/F1 can enable/disable the Sensor Port. (H: enable, L: disable) There is calibration (*) function on alternate ports of BU21010MUV. So the calibration port and no calibration port need pair to use. For example, SIN0 of the BU21010MUV can execute calibration, SIN1 can not and need to use a result of the SIN0 executed calibration. So disable the SIN0 and enable the SIN1 that is can’t permit. But opposite way is can permit. The ports are able to execute calibration and the other ports that pair of the calibration ports. Port Calibration SIN0 ○ SIN1 × SIN2 ○ SIN3 × SIN4 ○ SIN5 × SIN6 ○ use a result of the SIN0 executed calibration use a result of the SIN2 executed calibration use a result of the SIN4 executed calibration SIN7 × use a result of the SIN6 executed calibration ○：The port calibration ×：Not calibration port Each pair of ports needs to make the same size of electrode and the same length of wiring Example)SIN0-7, SIN8,SIN10,SIN12,SIN14 を ON, SIN9,SIN11,SIN13,SIN15 を OFF //LED port Setting Write ( F0h, 0Fh ) ●LED/PWM Setting ・Function description Enables LED LINK function, LEDs will turn ON/OFF when the sensor is sensing inputs or not. BU21010MUV LED PORT 8 LED LINK ○ ・LED Setting flow Even the LED ports are enabled when the sensor ports were enabled, the LED function will be unavailable. If using LED function, the sensor ports need to be disabled. START LED port Setting LED link Setting LED/PWM setting flow chart Example) In case of the BU21010MUV, odd ports for LED controlling and even ports for sensing. //LED port Setting Write ( F0h, 55h ) Write ( F2h, 0Fh ) www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 8/13 2009.04 - Rev.B Application Note BU21010MUV ●Power Management Setting ・Power management state transition. There are five states “normal”, “idle”, “calibration”, “configuration” and “initial calibration”. Idle : In this state, the sampling cycle will be 1/8 and power consumption can be decreased. Normal : Normal operating state. Calibration : In this state, controller detects the capacitance difference between reference capacitor (SREF) and sensor (SIN*) to execute the offset correction automatically Configuration :In this state, the initial setting does not be executed. Initial calibration :The function of the state is the same with the Calibration but different form state transition. START Power ON Configuration config done initial calibration calibration finish normal (INT="L") capacitive don't detect calibration capacitive detect calibration finish idle (INT="H") Power management state transition ・Power management flow chart as shown. With monitoring the INT pin can know the sensor that is detecting capacitance or not. When the sensor did not detect any capacitance, the HOST side is not necessary to read register. So the HOST side can stop accessing. In the “idle” state, the INT pin was “L” . So it also can detect the state when it return to “normal”. POWER ON Initial Setting INT="L" Regiser Read BTN: 0x32, 33 Gesture: 0x60,0x61,0x62 etc.. Wait Power management flow chart www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 9/13 2009.04 - Rev.B Application Note BU21010MUV ・It can know the state of the controller with the INT pin. “L” : Normal operating state. The controller is normal to sense. “H” : ”idle” state. A condition of INT pin when the “normal” state translate to the “idle” state, as shown in Fig. When the Sensor does not sense any capacitance, it will be the “idle” state with passing of BxN[sec] and the INT pin will be ”H”. content BU21010MUV A Sampling cycle system clock x 213 B Time for idle system clock x 219 N Setting Value of FAh Register SIN* CLOCK INT BxN A x 16 normal idle (1/16) A x 16 INT pin condition 1(normal → idle) A condition of INT pin when the “idle” state translate to the “normal” state, as shown in Fig. When the Sensor sense the capacitance, it will be the “normal” state with passing of Ax16x2[sec] . (1MHz :about 262msec) SIN* CLOCK INT ~ A x 16 A x 16 idle (1/16) normal INT pin condition 2(idle → normal) Example) The power save mode will not translate to the normal mode even the SIN8-15 are being touched. For the final touch with passing of 8 sec, It will translate to the power save mode. //Power management Setting Write ( F3h, F0h ) Write ( FAh, 1Fh ) ●Gain/Noise Setting ・Gain The Gain can adjust to x1~ x92. GAIN[2:0] 000 001 010 011 100 101 110 111 Adjustment value x1 x 4.22 x 8.4 x 16.5 x 23 x 46 x 69 x 92 Example) GAIN x8.4, disable Filter //Gain Setting Write ( FBh, 40h ) ・Noise For a countermeasure against noise, there are two kinds of the functions that are Noise Filter and Chattering Canceller. The Noise Filter can limit the fluctuation (Δ) of the ADC output. It can cause noise to decrease. The Chattering Canceller is a digital filter that can detect a sequence of sensing ON states to decrease noise. Analog value and XY processing of the BU21009MUV are only applied to the Noise Filter. ADC output Noise Filter Chattering Cancel Register 32h, 33h 8bit The circuit of noise www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 10/13 2009.04 - Rev.B Application Note BU21010MUV The Noise Filter limits the fluctuation (Δ) of the ADC output to decrease noise. For example, the ADC output is like ① of the Fig to set the fluctuation of every sampling cycle Δ. Then the following will be worsened like ② of the Fig. So it can decrease noise. ADC OUT ① ② Δ Time 1 sampling cycle Noise Filter The Chattering Canceller sampling setting. Setting Value Cancel Freq*1 [Hz] 0h - 1h 2h 3h 4h 5h 6h 7h 8h 9h Ah Bh Ch Dh Eh Fh 61.0 30.5 20.3 15.3 12.2 10.2 8.7 7.6 6.8 6.1 5.5 5.1 4.7 4.4 4.1 *1) If the internal frequency of 1MHz SIN* A A*2 01h A*3 02h 03h Chattering Canceller Example) Set the Noise Filter Δ 2 and the Chattering Cancel sampling 3//Noise Filter Write ( FBh, 12h ) // Chattering Cancel Write ( F6h, 03h ) ●Gesture The Gesture Function is used with combination of 4 sensor ports. That can detect direction, duration and speed when a finger is pressing. This function only can be used by BU21010MUV. Only the 4 sensor ports that are SIN0, SIN2, SIN4 and SIN6 have the Gesture Function to use. And they can not change to the other sensor ports. Dir：Right V e l： * * ** SIN0 SIN2 SIN4 SIN6 Gesture Image www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 11/13 2009.04 - Rev.B Application Note BU21010MUV For example detects the direction of the Gesture Function, as shown in Fig. At first read register of GES_DIR(62h). Next if a value of register GES_DIR is 01h or 02h, that is meaning the direction has been detected out. The value of the register GES_DIR will be kept until register GES_CLR(E2h) is written 80h to clear. START Setting Read ( 62h, 01h ) or Read ( 62h, 02h ) Read ( 60h, ** ) Read ( 61h, ** ) Write ( E2h, 80h ) Gesture Flow There are two modes that are the All detection mode and the Verbose mode to detect the gesture. All detection mode : Requires all sensors to be present in the sequence before the gesture is recognized. Verbose mode: Allows one or more of the keys to be missed in the sequence. Mode Value Direction (GES_DIR) Detected DIR_A 1)SIN0→SIN2→SIN4→SIN6 All detection 0 DIR_B 1)SIN6→SIN4→SIN2→SIN0 1)SIN0→SIN2→SIN4 2)SIN0→SIN2→ SIN6 DIR_A 3) SIN2→SIN4→SIN6 4)SIN0→ SIN4 5) SIN2→ SIN6 Verbose 1 1)SIN6→SIN4→SIN2 2)SIN6→SIN4→ SIN0 DIR_B 3) SIN4→SIN2→SIN0 4)SIN6→ SIN2 5) SIN4→ SIN0 Example) Set the value of the Gesture Mode 1 and Gesture maximum judgment time 1.9 sec. //Gesture Write ( E3h, 1Fh ) Write ( E4h, 00h ) Write ( E5h, FFh ) ●Config Done The register DONE (EFh) should be written 01h when all register have set up. And the controller will start to work. If any setting have to be changed when the controller is working, the register DONE (EFh) should be written 00h. After setting up write it 01h again. //Config done Write ( EFh, 01h ) ●Setting examples Write ( EDh, 01h ) Write ( F0h, FFh ) Write ( F1h, FFh ) Write ( F6h, 20h ) Write ( FBh, 71h ) Write ( FCh, 30h ) Write ( FDh, 03h ) Write ( EFh, 01h ) //Software Reset //Sensor Port Setting //Sensor Port Setting // Chattering Cancel 2 //GAIN*16 Noise FilterΔ1 //OFF -> ON Threshold //ON -> OFF Threshold //Done www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. 12/13 2009.04 - Rev.B Application Note BU21010MUV ●Ordering part number B U 2 Part No 1 0 1 0 M Part No U V - Package MUV : VQFN016V3030 E 2 Packaging and forming specification E2：Embossed tape and reel VQFN016V3030 3.0±0.1 3.0±0.1 0.5 5 13 0.75 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 ) 4 16 8 12 E2 9 1.4±0.1 0.4±0.1 1 3000pcs (0.22) 1.4±0.1 +0.03 0.02 –0.02 1.0MAX S C0.2 Embossed carrier tape Quantity Direction of feed 1PIN MARK 0.08 S Tape +0.05 0.25 –0.04 1pin (Unit : mm) www.rohm.com © 2009 ROHM Co., Ltd. All rights reserved. Reel 13/13 Direction of feed ∗ Order quantity needs to be multiple of the minimum quantity. 2009.04 - Rev.B Notice Notes No copying or reproduction of this document, in part or in whole, is permitted without the consent of ROHM Co.,Ltd. The content specified herein is subject to change for improvement without notice. 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