BS801B触摸感应按键芯片

BS801B/02B/04B/06B/08B

Features

·Operating voltage:2.2V~5.5V·Ultra low standby current:1.5mA at 3V ·Auto-calibration

·High reliability touch detections ·High PSRR

·Output type:Level-hold or Toggle ·One-key or Any-key Wake-up Mode

·Wake-up Mode set by pins or serial command ·Open drain NMOS output

·Key status monitored using pins or serial bus

General Description

The BS801B/02B/04B/06B/08Bare a range of 1to 8key touch key devices which can detect human body con-tact using external touch pads. The high level of device integration enable applications to be implemented with a minimum number of external components.

The BS804B and BS808B are equipped with a One-line serial interface to allow easy communication with an exter-nal MCU for device setup and for touch pin monitoring pur-poses.

Special internal circuitry is also employed to ensure excellent power noise rejection to reduce the possibility of false detections, increasing the touch switch applica-tion reliability under adverse environmental conditions. With auto-calibration, low standby current and a choice of wake-up features, this range of touch key devices provides a simple and effective means of implementing touch switches in a wide variety of applications.

Selection Table

Rev. 1.001July 7, 2009

Pin Description

The pins in the following table are common to all devices. The following table shows device specific pins. Note:It is important that the logic level of the OKW and LHF pins do not change state after power-on.

2

July 7, 2009

Rev. 1.00

Absolute Maximum Ratings

Supply Voltage ..........................V SS -0.3V to V SS +6.0VInput Voltage .............................V SS -0. 3V to V DD +0.3VI OL Total................................................................80mA Total Power Dissipation.....................................500mW

Storage Temperature ........................... -50°C to 125°C Operating Temperature .......................... -40°C to 85°C I OH Total.............................................................. -80mA

Note:These are stress ratings only. Stresses exceeding the range specified under ²Absolute Maximum Ratings ²may

cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability.

D.C. Characteristics

BS801B BS802B Ta=25°C

Ta=25°C

Rev. 1.003July 7, 2009

BS804B BS806B BS808B Ta=25°C

Ta=25°C

Ta=25°C

Rev. 1.004July 7, 2009

A.C. Characteristics

Ta=25°C

Functional Description

Introduction

This range of BS80xB touch key devices offer an easy and reliable means of implementing touch switch func-tions in a range of applications. A single external capaci-tor is the only external component required for most applications while a single line serial bus offers conve-nient communication with an external MCU. Device Operation Modes

All devices have two modes of operation, the Standby Mode and the Normal Mode. After the device is powered up it will automatically enter the Standby Mode

to con-serve power. The BS801B and BS802B devices can then be woken up by touching any of their Keyn pins. The BS804B, BS806B and BS808B devices can how-ever be woken up by either a One-key Wake-up using Key0, or by Any-key Wake-up. The wake-up method is determined by the status of the OKW pin which is read only during power-on. The advantage of

choosing the One-key wake-up option is that it consumes less power than the Any-key wake-up when in the Standby

Mode.

The logic status of the OKW pin is read when the device powers up. The logic level on this pin must not be changed after power on. Internal circuitry ensures that the internal pull-high resistor on the OKW pin will not consume current.

Operating Mode

Rev. 1.005July 7, 2009

When in the Standby Mode, after a relevant Keyn wake-up detection has been made, the device will switch to the Normal Mode and await subsequent switch detections on all their Keyn pins. It will remain in the Nor-mal Mode for about 10seconds for the BS801B and BS802B devices and for about 20seconds for the other devices and if no further detections are made during this time will return to the Standby Mode.

Touch Key Outputs

All Kout pins have NMOS structures to allow easy inter-facing to external devices with different operating volt-ages. The BS801B, BS802and BS804B devices can have their outputs configured to operate with either Level-Hold or Toggle type. The output type is deter-mined by the status of the LHF pin which is read during power-on. The logic level on this pin must not be changed after power on. Internal circuitry ensures that the internal pull-high resistor on the LHF pin will not consume current. The BS806B and BS808B only have Level-Hold output types.

Serial Interface -SCD

Both the BS804B and BS808B are equipped with a sin-gle line serial interface on the SCD pin, allowing for easy interfacing to an external MCU.

BS801B and BS802B Operating Flow

This single line interface allows communication in both directions between the touch key device and the external MCU. Using this interface, the external MCU can serially read the status of the touch keys at any time. The Serial interface also allows the external MCU to send com-mands to the touch key device. The serial interface al-

BS804B, BS806B and BS808B Operating Flow

Rev. 1.00

6

July 7, 2009

lows three functions to be implemented, two are initiated by the external MCU and one by the BS80xB.

read the key status. After this time has elapsed the de-vice will then transmit the data bits, D0~Dn.

Key Status Read Total Time

Each bit of transmitted data corresponds directly to a touch input key. Therefore the status of touch key Key0is represented by D0, Key1by D1and so on. A ²low ²bit means that a touch has been

detected, a ²high ²bit means no touch has been detected.

SCD Function Summary

·BS804B/BS808BWakes-up or Interrupts MCU

When any of the touch keys change state, a pulse will be generated by the BS804B/BS808Bdevice which can be used to wake up or to interrupt an external MCU. The MCU must ensure that its pin connected to the SCD pin is setup as an input to receive this pulse. The pulse width generated by the device is equal to a t SCD /2period where t SCD is about 76ms.

·MCU sends commands to BS804B/BS808Bdevice

Wake-up/InterruptPulse to MCU

·MCU reads the touch key status

The MCU can send a command to the BS804B/BS808B device to request the touch key status. The protocol for reading the touch key status is as follows:

¨

The MCU can send commands along the SCD line to setup the device in different Operating Modes. To do this the externally connected MCU takes control of the SCD line, first forcing it low and holding it low for a time of greater than 8t SCD cycles. This action will tem-porarily disable the device and enable it to receive the command from the MCU. Any command sent to the device from the MCU will override the original power on configuration setup.

The external MCU takes control of the SCD line and first sends three rising edge pulses or more to the BS804B/BS808Bwithin a time of about 152ms. The MCU then changes its I/Opin to an input. The BS804B/BS808Bdevice will then pull the SCD line low, then high, the timings are given by syn-chronise period. This allows the MCU to synchro-nise itself for the data transfer.

The BS804B/BS808Bdevice will then transmit its key status, given by D0~Dn

--

¨¨

SCD Device Setup

The desired Operating Mode to be setup depends upon the number of pulses received by BS804B/BS808B within a time period, 4t SCD , as shown in the table. After the programming clock cycles have been transmitted and the SCD

line returns high, the device will return to normal operation. BS804B and BS808B SCD Commands

¨

For the BS804B, the data format is D0~D3.For the BS808B, the data format is D0~D7.

¨

The MCU can then read the key status taking care to read the data in the centre of the transmitted data pulse.

After the last data bit is transferred the BS804B/BS808Bdevice will return its SCD pin to an input state.

¨

The timings associated with the above protocol can be described in multiples of the SCD clock periods. The SCD clock period is about about 76ms.

A certain time is required for the MCU to transmit three or more pulses to

inform the device that it desires to Rev. 1.00

7

July 7, 2009

SCD Pin Touch Key Status Request

Note that the MCU must transmits these pulses within 4t SCD .

Maximum Key On Duration Time

To minimise the possibility of unintentional switch detec-tions, such as undesired objects covering the sense electrodes, the devices includes a Maximum Key-On duration time function. To implement this function the devices include an internal timer, which starts running after each switch detection. If the key on time of a touch key exceeds a value of about 40seconds, then the de-vice will be reset to its power-on condition and initiate a new auto calibration. The output will then remain inac-tive until the next switch detection. Auto-calibration Function

The devices include a full auto-calibration function which will be initiated after the device is powered-on. In addition to the power-on calibration, if no switch detec-tion has been made for more than about 2.5seconds then a further calibration procedure will be carried out. The calibration is applied independently to each chan-nel on the devices. By implementing this feature, changes in the touch key environmental conditions are automatically catered for dynamically.

An external capacitor, Cs, connected to the Cref pin, is used to set the overall sensitivity of all pins. Some of the most important factors affecting sensitivity are the fol-lowing:

·Cref capacitor value -Cs

The purpose of the Cs capacitor is to allow for adjust-ment of touch key sensitivity and power noise rejec-tion. The optimal choice of sensitivity and power noise rejection will be obtained when the value of the Cs ca-pacitor is equivalent to the touch pad capacitance, however the value can still be changed to obtain the required sensitivity value. Higher Cs values will result in higher levels of sensitivity. Recommended values for Cs are between 0pF and 10pF.

·Touch key pad size

Larger touch key sizes will increase sensitivity and of course vice-versa, small electrode sizes will decrease sensitivity.

·Touch key pad insulating panel thickness

A thinner panel will result in higher sensitivity and of course thicker panels will result in a lower sensitivities.

·Touch key pad insulating panel material

The choice of the dielectric material for the panel will in-fluence the sensitivity. Materials with higher dielectric constants will result in higher sensitivities and lower di-electric constants will result in lower sensitivities.

Sensitivity Adjustment

The sensitivity of the switch is a very important consider-ation in most applications whose requirements will vary according to the user application. The user should therefore be aware of the factors which will affect the overall sensitivity of their touch key application. Factors to take into consideration include the electrode size and the capacitance of the connection lines from the elec-trode to the BS80xB device. Therefore the sensitivity will vary according to the actual PCB layout and design.

Touch Key

Cs 0pF~10pF

Key Cref

Rev. 1.008July 7, 2009

Application Circuit

Touch Key

VDD

Touch Key0Touch Key1

VDD

VDD

Touch Key0Touch Key3

BS804B

Note:

If the output is connected to an MCU input with an internal pull high resistor then the pull high resistor on the ap-plication circuit is not required.

Rev. 1.009July 7, 2009

Touch Key0

Touch Key5

VDD

VDD

Touch Key0

Touch Key7

Note:

If the output is connected to an MCU input with an internal pull high resistor then the pull high resistor on the ap-plication circuit is not required.

Rev. 1.0010July 7, 2009

Package Information

8-pin SOP (150mil)Outline Dimensions

·MS-012

Symbol A B C C ¢D E F G H a

Dimensions in mil

Min. [1**********]¾¾41670°

Nom. ¾¾¾¾¾50¾¾¾¾

Max. [1**********]69¾1050108°

Rev. 1.0011July 7,

2009

·MS-012

Symbol A B C C ¢D E F G H a

Dimensions in mil

Min. [1**********]¾¾41670°

Nom. ¾¾¾¾¾50¾¾¾¾

Max. [1**********]69¾1050108°

Rev. 1.0012July 7, 2009

·MS-013

Symbol A B C C ¢D E F G H a

Dimensions in mil

Min. [1**********]¾¾41680°

Nom. ¾¾¾¾¾50¾¾¾¾

Max. [1**********]104¾1250138°

Rev. 1.0013July 7,

2009

Symbol A B C C ¢D E F G H a

Dimensions in mil

Min. [1**********]9¾41570°

Nom. ¾¾¾¾¾25¾¾¾¾

Max. [1**********]65¾1050108°

Rev. 1.0014July 7,

2009

6-pin SOT23-6Outline Dimensions

Symbol A A1A2b C D E e H L q

Dimensions in mm

Min. 1.0¾0.70.350.12.71.4¾2.60.371°

Nom. ¾¾¾¾¾¾¾1.9¾¾¾

Max. 1.30.10.90.500.253.11.8¾3.0¾9°

Rev. 1.0015

July 7, 2009

Product Tape and Reel Specifications

Reel Dimensions

SOP 8N

Symbol A B C D T1T2

Description

Reel Outer Diameter Reel Inner Diameter Spindle Hole Diameter Key Slit Width

Space Between Flange Reel Thickness

Dimensions in mm

330.0±1.0100.0±1.513.0

+0.5/-0.2

2.0±0.512.8

+0.3/-0.2

18.2±0.2

SOP 16N (150mil)

Symbol A B C D T1T2

Description

Reel Outer Diameter Reel Inner Diameter Spindle Hole Diameter Key Slit Width

Space Between Flange Reel Thickness

Dimensions in mm

330.0±1.0100.0±1.513.0

+0.5/-0.2

2.0±0.516.8

+0.3/-0.2

22.2±0.2

Rev. 1.0016July 7, 2009

SOP 20W

Symbol A B C D T1T2

Description

Reel Outer Diameter Reel Inner Diameter Spindle Hole Diameter Key Slit Width

Space Between Flange Reel Thickness

Dimensions in mm

330.0±1.0100.0±1.513.0

+0.5/-0.2

2.0±0.524.8

+0.3/-0.2

30.2±0.2

SSOP 20S (150mil)

Symbol A B C D T1T2

SOT23-6

Symbol A B C D T1T2

Description

Reel Outer Diameter Reel Inner Diameter Spindle Hole Diameter Key Slit Width

Space Between Flange Reel Thickness

Dimensions in mm

178.0±1.062.0±1.013.0±0.22.50±0.258.411.4

+1.5/-0.0+1.5/-0.0

Description

Reel Outer Diameter Reel Inner Diameter Spindle Hole Diameter Key Slit Width

Space Between Flange Reel Thickness

Dimensions in mm

330.0±1.0100.0±1.513.0

+0.5/-0.2

2.0±0.516.8

+0.3/-0.2

22.2±0.2

Rev. 1.0017July 7, 2009

Carrier Tape Dimensions

SOP 8N

Symbol W P E F D D1P0P1A0B0K0t C

Cavity Pitch Perforation Position

Cavity to Perforation (WidthDirection) Perforation Diameter Cavity Hole Diameter Perforation Pitch

Cavity to Perforation (LengthDirection) Cavity Length Cavity Width Cavity Depth

Carrier Tape Thickness Cover Tape Width

Description

Carrier Tape Width

Dimensions in mm

12.0

+0.3/-0.1

8.0±0.11.75±0.15.5±0.11.55±0.11.50

+0.25/-0.00

4.0±0.12.0±0.16.4±0.15.2±0.12.1±0.10.30±0.059.3±0.1

SOP 16N (150mil)

Symbol W P E F D D1P0P1A0B0K0t C

Rev. 1.00

Cavity Pitch Perforation Position

Cavity to Perforation (WidthDirection) Perforation Diameter Cavity Hole Diameter Perforation Pitch

Cavity to Perforation (LengthDirection) Cavity Length Cavity Width Cavity Depth

Carrier Tape Thickness Cover Tape Width

18

Description

Carrier Tape Width

Dimensions in mm

16.0±0.38.0±0.11.75±0.17.5±0.11.551.50

+0.10/-0.00+0.25/-0.00

4.0±0.12.0±0.16.5±0.110.3±0.12.1±0.10.30±0.0513.3±0.1

July 7, 2009

Symbol W P E F D D1P0P1A0B0K0t C

Description

Carrier Tape Width Cavity Pitch Perforation Position

Cavity to Perforation (WidthDirection) Perforation Diameter Cavity Hole Diameter Perforation Pitch

Cavity to Perforation (LengthDirection) Cavity Length Cavity Width Cavity Depth

Carrier Tape Thickness Cover Tape Width

Dimensions in mm

24.0

+0.3/-0.1

12.0±0.11.75±0.1011.5±0.11.51.50

+0.1/-0.0+0.25/-0.00

4.0±0.12.0±0.110.8±0.113.3±0.13.2±0.10.30±0.0521.3±0.1

SSOP 20S (150mil)

Symbol W P E F D D1P0P1A0B0K0t C

Description

Carrier Tape Width Cavity Pitch Perforation Position

Cavity to Perforation (WidthDirection) Perforation Diameter Cavity Hole Diameter Perforation Pitch

Cavity to Perforation (LengthDirection) Cavity Length Cavity Width Cavity Depth

Carrier Tape Thickness Cover Tape Width

Dimensions in mm

16.0

+0.3/-0.1

8.0±0.11.75±0.107.5±0.11.51.50

+0.1/-0.0+0.25/-0.00

4.0±0.12.0±0.16.5±0.19.0±0.12.3±0.10.30±0.0513.3±0.1

Rev. 1.0019July 7, 2009

Symbol W P E F D D1P0P1A0B0K0t C

Description

Carrier Tape Width Cavity Pitch Perforation Position

Cavity to Perforation (WidthDirection) Perforation Diameter Cavity Hole Diameter Perforation Pitch

Cavity to Perforation (LengthDirection) Cavity Length Cavity Width Cavity Depth

Carrier Tape Thickness Cover Tape Width

Dimensions in mm

8.0±0.34.0±0.11.75±0.103.50±0.051.51.5

+0.1/-0.0+0.1/-0.0

4.0±0.12.00±0.053.15±0.103.2±0.11.4±0.10.20±0.035.3±0.1

Rev. 1.0020July 7, 2009

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Fax:886-3-563-1189

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http://www.holtek.com

Copyright Ó2009by HOLTEK SEMICONDUCTOR INC.

The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek as-sumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. Holtek ¢s products are not authorized for use as critical components in life support devices or systems. Holtek reserves the right to alter its products without prior notification. For the most up-to-date information, please visit our web site at http://www.holtek.com.tw.

Rev. 1.0021July 7,

2009