LDS6202NTGI8 - IDT, Integrated Device Technology Inc

LDS6200 Family

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Doc. No. 6200DS, Rev. 0.5

Characteristics subject to change without notice

PureTouch

®

* Low Channel Capacitive Touch Sensor IC Family

FEATURES

o Up to 8 touch sensor channels

o 2ms update rate per active sensor input**

o Built-in Slider/Scroll Support

o Configurable hysteresis and debounce

o Touch Preference Modes

o 1.65-5.5v supply voltage

o Low touch sensor operating power

o Full power mode (typ): <125uW***

o Optional low power mode

o On-chip automatic calibration algorithm

o I

2

C compatible serial I/F with VDDIO

o Power on touch detection

o Configurable for proximity sensing

o GPIO and interrupt output

o 3mm x 3mm 16-pin and 20-pin TQFN

packages

o SOIC packages also available

APPLICATIONS

o Mobile handsets, personal media players

o Portable navigation devices

o Remote controls

o Office equipment, multi-function printers

o Set top boxes

o Home appliances

o Brown goods

o Industrial controls

DESCRIPTION

The LDS6200 Family of capacitive touch controllers

enables streamlining of the human-machine interface

through the implementation of touch-based user

inputs such as touch buttons, sliders, and scroll

wheels. Employing a finely tuned sigma-delta

capacitance-to-digital converter and proprietary

noise-filtering algorithms, each device is able to

reliably sense small changes in capacitance, allowing

touch-based inputs to replace a side variety of

mechanical input types. On-chip automatic

calibration accounts for environmental changes such

as temperature, humidity, and dust and is executed

automatically.

The LDS6200 Family consists of four products with

up to 8 capacitive sensor input pins.

Part # Touch Sensors Package

LDS6201 Up to 2 16ld TQFN

16ld SOIC

LDS6202 Up to 4

LDS6203 Up to 6 20ld TQFN

20ld SOIC

LDS6204 Up to 8

The LDS6200 Family supports touch sensor supply

voltages from 1.65 to 5.5V. All parts support I

2

C

compatible serial interfaces and offer both a General

Purpose I/O (GPIO) and VDDIO support, enabling

1.65V to 5.5V voltage interface support. Typical

touch sensor operating power for the device is less

than 125uW***. Package offerings include thin form

factor 3mm x 3mm 16-pin TQFN, 3mm x 3mm 20-pin

TQFN, 3.9mm x 9.9mm 16-pin SOIC, 7.5mm x

12.8mm 20-pin SOIC.

* PureTouch is a registred trademark of IDT

** Nominal decimation rate (d=1024), per sensor input

*** 1.8V, excluding VDDIO current, which varies with VDDIO voltage, I/F type, and communication frequency

LDS6200 Family

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Characteristics subject to change without notice

TYPICAL APPLICATION CIRCUIT FOR DUAL SUPPLY VOLTAGES

C0

SHIELD

SENSOR PCB

SCLK

SDA

SCLK

SDA

Host

Processor

With I2C

VDDIO VDD

VDDIO (1.65V~5.5V)

INTB INTB

RPU

GPIO

TEST1

floating

RESETBRESETB

RPU

VDD

VSS

VDD* (1.65V~1.95V)

C1, C2 > 1uF

C1

*For direct application of 1.8V voltage.

LDOEN

TEST0

C1

C2

C3

C4

C6

C5

C7

RPU

C2

Figure 1: Application Circuit with I

2

C I/F using dual voltage sources

LDS6200 Family

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Characteristics subject to change without notice

TYPICAL APPLICATION CIRCUIT FOR SINGLE SUPPLY VOLTAGE

C0

SHIELD

SENSOR PCB

SCLK

SDA

SCLK

SDA

Host

Processor

With I2C

VDDIO VDD

VDDIO (1.65V~5.5V)

INTB INTB

RPU

GPIO

TEST1

floating

RESETBRESETB

RPU

VDD

VSS

VDDIO* (1.65V~5.5V)

C1, C2 > 1uF

*For voltages >1.95V, apply voltage to VDDIO and tie VDD to ground through C1

LDOEN

TEST0

C1

C2

C3

C4

C6

C5

C7

C1

C2

RPU

Figure 2: Application Circuit with I

2

C I/F using single voltage source

LDS6200 Family

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Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

ABSOLUTE MAXIMUM RATINGS

Item Symbol Rating Unit

Touch Sensor Supply Voltage VDD -0.3 to +6.0 V

Serial Interface Operating Voltage VDDIO -0.3 to +6.0 V

Input voltage range (Digital) VIN -0.3 to VDDIO +0.3 V

Input voltage range (Analog) AVIN -0.3 to VDD +0.3 V

Output voltage range (Digital) VOH -0.3 to VDDIO +0.3 V

Output voltage range (Analog) AVOH -0.3 to VDD +0.3 V

Operating Temperature Range T

OPR

-40 to +85 °C

Storage Temperature Range T

STG

-55 to +125 °C

ESD PROTECTION LEVEL

Model Test condition Rating Unit

Human Body Model C = 100pF, R = 1.5kΩ 8000 V

Charge Device Model Charging Resistor = 300MΩ 1500 V

Machine Model C = 200pF, R = 0Ω 400 V

RECOMMENDED OPERATING CONDITIONS

Parameter Condition Unit

VDD* 1.65 to 1.95 V

VDDIO 1.65 to 5.5 V

Ambient Temperature Range -40 to +85 °C

* For supply voltages >1.95V, apply to VDDIO pin and tie VDD pin to GND through C1

Typical application circuit shown on page 3

LDS6200 Family

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Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

ELECTRICAL OPERATING CHARACTERISTICS

VDD = 1.8V, VDDIO = 1.8V T

AMB

= -40°C to +85°C unless otherwise specified

Parameter Symbol Conditions Related Pins Min Typ Max Unit

Power & Operating Voltage -

Operating Voltage(1) : Touch* VDD - VDD 1.65 1.8 1.95 V

Operating Voltage(3) : Touch - I/O VDDIO - VDDIO 1.65 - 5.5 V

Logic Inputs

High Level Input Voltage VIH - (*1) 0.7*VDDIO V

Low Level Input Voltage VIL - (*1) VSS 0.3*VDDIO V

Input Leakage Current IIL VIN= VDDIO or VSS (*1) -1 uA

Logic Outputs

High Level Output Voltage VOH IOH= -1mA (*2) 0.8*VDDIO V

Low Level Output Voltage VOL IOL= +1mA (*2) 0.2*VDDIO V

Capacitance-to-Digital Converter

CDC Update Rate per Active Sensor Tcdc (*3) 1.95 2.05 2.15 ms

CIN Input Leakage IILcin IOH= -1mA C0~Cx nA

Sensor Capacitance Csensor 25 (*4) pF

* For supply voltages >1.95V, apply to VDDIO pin, set LDOEN to logic high, and tie VDD1 pin to GND through C1

Typical application circuits shown on page 2 and 3

NOTE: (*1): SCLK, SDA, GPIO; (*2): SDA, INTB, GPIO; (*3) DECIMATION RATE = 1024, PER UTILIZED SENSOR; (*4): MAXIMUM

SENSOR CAPACITANCE MAY BE ALLOWED TO EXCEED 25PF DEPENDING UPON SYSTEM CONDITIONS – CONTACT IDT FOR

EXCEPTION CONDITIONS

LDS6200 Family

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Characteristics subject to change without notice

ELECTRICAL OPERATING CHARACTERISTICS (CURRENT CONSUMPTION)

VDD = 1.8V, VDDIO = 1.8V, T

AMB

= -40°C to 85°C unless otherwise specified

Parameter Symbol Conditions Related Pins Min Typ Max Unit

Current Consumption

Full Power Mode Iddfp 55 100 uA

Sleep Mode Iddsl 17 uA

Shutdown, T

AMB

= 25°C Iddsd T

AMB

= 25°C 0.5 5 uA

Shutdown Iddsd

T

AMB

= -40°C to

+85°C 10 uA

LDS6200 Family

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Characteristics subject to change without notice

I

2

C-COMPATIBLE TIMING SPECIFICATIONS

For VDD = 1.65-1.95V, VDDIO = 1.65V to 5.5V, over ambient temperature range -40ºC to +85ºC.

Parameter

Tmin

Tma

x

Unit

Description

f

SCLK

400 kHz SCLK clock frequency

t

R

300 ns Clock/data rise time

t

F

300 ns Clock/data fall time

t

HD:STA

0.6 µs Start condition hold time

t

SLW

1.3 µs Clock low period

t

SHW

0.6

µs Clock high period

t

SU:DAT

100

ns Data setup time

t

HD:DAT

0

ns Data hold time

t

SU:STO

0.6

µs Stop condition setup time

t

SU:STA

0.6

µs Start condition setup time

t

BUF

1.3

µs Bus free time between stop and start conditions

t

SP

50 ns Max spike width suppressed by SCLK and SDA inputs

t

VD:DAT

0.9 µs Data valid time

t

VD:ACK

0.9 µs Data valid acknowledge time

Figure 3: I

2

C-Compatible Detailed Timing Diagram

LDS6200 Family

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Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

WRITING AND READING OVER THE I

2

C-COMPATIBLE INTERFACE

The LDS6200 Family is always a slave on the I

2

C interface bus and uses the 7-bit device address of 0101 100.

Data transfer utilizes 8-bit bytes, with the master initiating a data transfer (START) by taking SDA from high-to-low

while keeping SCLK high, followed by the 7-bit device address plus a read/write bit dictating the direction of data

transfer (read=1, write=0). Data is sent over a series of 9 clock pulses made up of 8 bits of data and an

acknowledge bit from the LDS6200 Family. The STOP condition occurs when SDA is taken from low-to-high while

keeping SCLK high, upon which the LDS6200 Family resets its address pointer to 0x000 and the serial interface

pins enter the idle state. Data must be transitioned when the clock signal is low and remain stable when SCLK is

high, as a low-to-high transition on SDA when SCLK is high would be interpreted as a STOP signal.

WRITING DATA OVER I

2

C

The device address (0101 100) and read/write bit (0 for writing) are sent over the bus, followed by two data bytes

containing the 10-bit register address to be written. The upper and lower register address bits are shown below:

MSB

LSB

7

6

5

4

3

2

1

0

XXXXXX

Register

Addr Bit 9

Register

Addr Bit 8

MSB

LSB

7

6

5

4

3

2

1

0

Register

Addr Bit 7

Register

Addr Bit 6

Register

Addr Bit 5

Register

Addr Bit 4

Register

Addr Bit 3

Register

Addr Bit 2

Register

Addr Bit 1

Register

Addr Bit 0

The third and fourth data bytes contain the 8 MSBs and LSBs, respectively, to be written to the internal register

pointed to by the 10-bit register address.

Figure 4: I

2

C-Compatible Register Write

The LDS6200 Family automatically increments the address pointer enabling sequential writes to registers in the

same write transaction. Finishing the transaction involves the master generating a stop condition on SDO or repeat

start condition if the I

2

C link is to remain active.

LDS6200 Family

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Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

READING DATA OVER I2C

To initiate a read operation, the master must first write the read starting address to the LDS6200 Family. The

device address (0101 100) and read/write bit (0 for initial write of starting address) is sent over the bus, followed by

two data bytes that contain the 10-bit register address to be read. The address format is identical to that used

during write operations, with only the 10 lower bits of the 16-bit address word containing address information.

The master then either ends the write operation with a STOP signal followed by initiation (START) of a read

operation, or more ideally, issues a “REPEAT START” command. In both cases, the read/write bit is set to “1” (see

Figure 9 for details of both continuations methods). In either case, the LDS6200 Family provides the MSB eight

bits of data first, followed by the LSB eight bits in the next byte.

Figure 5: I

2

C-Compatible Detailed Timing Diagram

The LDS6200 Family address pointer automatically increments after each read, resulting in a continuous output of

read data until the master returns a no acknowledge (ACK signal high) and stop condition to the bus. If the address

pointer reaches its maximum value and the master continues to attempt to read from the part, the LDS6200 Family

continues to send data from the last register that was addressed.

LDS6200 Family

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Characteristics subject to change without notice

DEVICE PINOUTS (QFN)

LDS6201NTGI

TEST1

RESETB

VSS

LDOEN

VDDIO

TEST0

INTB

SHIELD

LDS6200 Family

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Characteristics subject to change without notice

LDS6202NTGI

1

2

3

4

12

11

10

9

5 6 7 8

16 15 14 13

C3

C2

C1

C0

VDD

GPIO

SDA

SCLK

TEST1

RESETB

VSS

LDOEN

VDDIO

TEST0

INTB

SHIELD

LDS6200 Family

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Characteristics subject to change without notice

LDS6203NTGI

1

2

3

4

15

14

13

12

6 7 8 9

20 19 18 17

C5

C4

C3

C2

VDDIO

VDD

SCLK

GPIO

16

11 SDA

10

5

C1

LDS6200 Family

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Characteristics subject to change without notice

LDS6204NTGI

1

2

3

4

15

14

13

12

6 7 8 9

20 19 18 17

C5

C4

C3

C2

VDDIO

VDD

SCLK

GPIO

SHIELD

TEST1

C7

TEST0

VSS

C6

RESETB

C0

16

LDOEN

11 SDA

10

INTB

5

C1

LDS6200 Family

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Characteristics subject to change without notice

DEVICE PINOUTS (SOIC)

LDS6201DCGI

VSS

TEST0

N.C. VDD

TEST1

C1

C0

SHIELD

SCLK

INTB

GPIO

SDA

RESETB

VDDIO

N.C.

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

LDOEN

LDS6200 Family

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Characteristics subject to change without notice

LDS6202DCGI

VSS

TEST0

C3 VDD

TEST1

C1

C0

SHIELD

SCLK

INTB

GPIO

SDA

RESETB

VDDIO

C2

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

LDOEN

LDS6200 Family

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Characteristics subject to change without notice

LDS6203SOGI

TEST0

N.C.

C0

C1

C4

C3

C2

GPIO

SDA

TEST1

RESETB

INTB

LDOEN

C5

1

2

3

4

5

6

7

8

9

10

20

19

18

17

16

15

14

13

12

11

SHIELD

SCLK

VDD

VSS

VDDIO

LDS6200 Family

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Characteristics subject to change without notice

LDS6204SOGI

TEST0

C7

C6

C0

C1

C4

C3

C2

GPIO

SDA

TEST1

RESETB

INTB

LDOEN

C5

1

2

3

4

5

6

7

8

9

10

20

19

18

17

16

15

14

13

12

11

SHIELD

SCLK

VDD

VSS

VDDIO

LDS6200 Family

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Characteristics subject to change without notice

PIN LIST and FUNCTIONAL DESCRIPTIONS

Pin Name

Functional Description

Cx Dedicated Capacitance Sensor Input

VDD Touch Sensor Supply Voltage (1.8V nominal, LDO Disabled)

VSS Touch Sensor Ground

LDOEN LDO Enable

(“0” = LDO Disable, 1.8V applied directly to VDD pin)

(“1” = LDO Enable, Supply Voltage Applied to VDDIO)

VDDIO Touch Sensor Supply Voltage (>1.95V, LDO Enabled) and/or Serial I/F

Operating Voltage

SDA I

2

C Data I/O

SCLK I

2

C Clock Input

GPIO General Purpose Input Output

INTB Interrupt Output (CMOS Output)

RESETB Hardware Reset pin for device (Active low)

SHIELD CDC Shield. Connect to external shield/plane to reduce stray capacitance.

TEST0 Test pin must be connected to ground

TEST1 Test pin must be connected to ground

N.C. No Connect

(must

be left floating)

LDS6200 Family

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Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

FUNCTIONAL BLOCK DIAGRAM

Switch

Matrix

Figure 6: LDS6200 Family Functional Block Diagram

LDS6200 Family

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Characteristics subject to change without notice

THEORY OF OPERATION

The LDS6200 PureTouch

®

Family of capacitive touch

controllers feature a highly-accurate capacitance-to-

digital converter (CDC) for touch button, slider, and

scroll applications. Capacitive sensing is

accomplished using a sigma-delta converter capable

of converting a sensor input signal into a digital

output that is compared against a touch/no-touch

threshold value to determine if a touch has occurred.

The button status and digitized capacitance values

are stored in on-chip registers available to a host

processor via the I

2

C or SMBus-compatible serial

interface options.

On-chip self-calibration continously takes

environmental effects such as temperature, humidity,

and dust into consideration to establish an accurate

baseline capacitance for each sensor to ensure

maximum responsiveness to true touch events.

The LDS6200 Family includes up to 8 sensor input

pins, with a programmable switch matrix determining

which sensor inputs are connected to the CDC at any

given time. The sensor inputs may be connected to

external capacitance sensors arranged as buttons,

sliders, scroll wheels or other creatively arranged

user inputs. Button, slider, and scroll inputs are

natively supported using built in logic, with location

and direction automatically calculated for slider and

scroll inputs.

On-chip registers allow adjustment of the sampling

(decimation) rate, threshold/sensitivity for each

individual sensor, and hysteresis and debounce

characteristics, enabling a very high degree of

configurability in scan rate, button sensitivity and

overall touch characteristics.

An interrupt output, INTB, is available to notify the

host when a touch event has occurred. A GPIO is

also available to act as an input to control the INTB

output. The GPIO pin may also be configured as an

output low or output high pin to turn on and off an

external LED.

Due to its ultra-low touch sensor power consumption

of <125uW*** (typ), the LDS6200 Family may be

operated continuously at full power to achieve the

most responsive touch charactersitics and best

possible user experience. In this mode, touch sensor

detection occurs continuously at very low power

levels, eliminating the need for sleep periods

between detection cycles that result in touch latency

and an inconsistent user experience.

The LDS6200 Family operates with supply voltages

ranging from 1.8V to 5.5V. Available package

options vary by device and include two thin form

factor 3mm x 3mm 16-pin and 3mm x 3mm 20-pin

TQFN packages, and 3.9mm x 9.9mm 16-pin or

7.5mm x 12.8mm 20-pin SOIC packages.

*** 1.8V, excluding VDDIO current, which varies with VDDIO

voltage, I/F type, and communication frequency

LDS6200 Family

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Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

OPERATING MODES

The LDS6200 Family may be programmed to operate

in three different modes.

In full power mode, touch detection occurs

continuously, without delays between detection

cycles. This mode is utilized when the touch inputs

need to be fully active and always responsive to

touch inputs. Due to its ultra-low touch sensor power

consumption of <125uW***, the LDS6200 Family may

be operated continuously in full power mode even

when battery life is of premium importance.

The device may also be put into a configurable low

power mode for situations where a small inserted

delay (typically less than 0.3s) between the first touch

and touch reporting is acceptable. This optional low

power mode can cut power by more than half.

Lastly, the device can be put into Shutdown mode,

which disables touch sensing and lowers power

consumption to ~1uW (typical). Only the serial

interface bus is active during Shutdown mode to

receive any commands (such as exit from Shutdown

mode).

Two methods of device reset are provided. Software

Reset (writing any value to register 0x001) executes

a soft reset of the device by initiating a new

calibration cycle and resetting the state machine,

including the Interrupt Status Register. Previously

configured control registers, however, are not

affected by a Software Reset, so no reconfiguration

or re-initialization need occur.

Hardware Reset (setting RESETB low or writing

any value to register 0x000) resets the state

machine and all previously configured registers,

requiring a re-initialization by the host to set

configuration registers to their proper state.

Both Software and Hardware Reset take ~0.5-1s in

the typical case to return the device to its fully

functioning state. The actual time depends upon the

number of active sensors requiring calibration and

the relative sensor values. Where start-up time is

especially important, fine-tuning of certain

configuration registers is possible to expedite initial

calibration. Please contact your IDT representative if

start-up time optimization is required.

POWER-UP/INITIALIZATION SEQUENCE

The power up and initialization sequence involves the

following flow:

Power-Up

→

Cold Reset Command

→

Initialize

Configuration Registers

→

Software Reset Command

Initialization of the configuration registers is required

to define the functionality of each channel, set touch

sensitivity levels, and generally specify the desired

configuration of the highly flexible LDS6200 Family

touch controller. The Cold Reset and Software Reset

Commands are required to ensure consistency of

operation before and after the initialization process

occurs.

AUTOMATIC CALIBRATION MODE

The LDS6200 Family integrates on-chip sensor

calibration to compensate for uncontrollable

environmental factors such as moisture and

temperature changes. Without such compensation,

the baseline “no-touch” value may drift over time,

affecting the ability of the device to measure valid

touch events. The calibration algorithm is executed

after every conversion cycle, ensuring that even

rapidly changing ambient conditions are well

compensated.

*** 1.8V, excluding VDDIO current, which varies with VDDIO

voltage, I/F type, and communication frequency

LDS6200 Family

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Characteristics subject to change without notice

LOW POWER MODE CONFIGURATION

Low power mode may be utilized when extremely low

power consumption is desired and a small amount of

added delay/latency is acceptable. By setting Bit 1 of

the Power Configuration Register (0x002) to “1”, low

power mode is activated and the touch controller will

alternate between full power sensing and a lower

power sleep mode where power is conserved but

touches are not sensed.

The amount of power saved is a function of the sleep

period time inserted between full power scan cycles.

The full power scan cycle time is equal to ~2ms x the

number of active sensors. For example, 10 active

sensors would result in a full power scan cycle time

of ~20ms.

The amount of sleep time inserted occurs in 1ms

increments by setting the Sleep Configuration

Register (0x056) to the # of milliseconds desired for

the sleep cycle. For example, a setting of 50

(decimal) will insert 50ms of sleep time, lowering the

average power consumption compared to a

continuous full power state. The longer the sleep

period added, the lower the average power

consumption will be, with the trade-off of longer

potential latency between touch and touch

recognition

The following tables show that low power mode

current consumption is a function of not only the

inserted sleep period, but also the number of active

sensors. It should also be noted that the greatest

power savings benefit is realized when adding the

first ~250ms of sleep period (less when fewer

sensors are active). When adding sleep periods

longer than ~250ms, the resulting reduction in current

is relatively minor. Accordingly, the system designer

should take into consideration the # of active sensors

and incremental power savings when deciding upon

the sleep period, as it may not be materially

beneficial to insert longer sleep periods.

In an example scenario of 8 active sensors, current

consumption may be lowered to ~24uA*** (>60%

current reduction) when introducing a relatively brief

100ms of sleep. Adding an additional 150ms of sleep

(for 250ms total) only saves an additional 4uA.

Once a touch is detected, the touch controller will

remain in full power mode, maximizing touch

responsiveness, until a certain amount of time

passes without a touch event. The Sleep Wait

Register (0x003) specifies the time the controller will

remain in full power mode (waiting for a new touch)

before going back to low power mode.

*** 1.8V, excluding VDDIO current, which varies with VDDIO

voltage, I/F type, and communication frequency

LDS6200 Family

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Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

SELECTIVE TOUCH MODES

The LDS6200 Family touch controller is capable of

detecting up to 8 simultaneous touches (on

LDS6204). However, in certain situations, the

application may want to only allow one or two valid

touch events at any given time.

To accommodate such application requirements and

avoid inadvertent touches, the LDS6200 Family has

four selective touch modes: Strongest Absolute

Touch and Two Strongest Absolute Touches. As

the names indicate, Strongest Absolute Touch mode

only registers the single strongest touch event at any

given time, as judged by the absolute capacitance

value, as long as it is above the touch threshold value.

Similarly, Two Strongest Absolute Touches mode

only registers the two strongest touch events at any

given time, as judged by absolute capacitance values.

New to the LDS6200 Family are Strongest Relative

Touch and Strongest Two Relative Touches.

Instead of judging strongest touch by absolute

capacitance value, the judgments are made looking

at the delta between measured capacitance value

and touch threshold value. The largest

delta

(defined as “capacitance value minus threshold level”

for each sensor) is considered the strongest relative

touch (and largest two deltas considered the two

strongest relative touches). Where sensor sizes (and

therefore the resulting capacitance values resulting

from a touch) are significantly different, these two

new modes can help achieve the desired effect of

registering the most definitive/intended touch or

touches.

Bits 8 and 9 of the “Touch Configuration Register”

(0x040) control whether selective touch is active (Bit

8/9 = 1/0 for Strongest Touch, 0/1 for Two Strongest

Touches). The device defaults to the unrestricted or

“all touch” mode (Bits 8 and 9 = 0) upon power up.

To select between Absolute and Relative touch

preference modes, a single bit RELATIVE_EN (bit 15

of Register 0x075) is utilized, with bit status “0” used

for the Absolute modes and bit status “1” used for the

Relative Modes.

To avoid frequent toggling of the strongest touch with

two touches of comparable strength, an additional

(optional) time criteria may be added that requires a

new and stronger touch to remain stronger for a

certain period of time before replacing the current

strongest touch. The REPLACEMENT_TIME bits (0-

15 of Strongest Touch Replacement Time

Configuration Register 0x028) are used for this

purpose. This option is available in Strongest Touch

mode (Absolute or Relative) only and is not

applicable to Two Strongest Touch modes.

RECALIBRATION FOR “STUCK” TOUCHES

The LDS6200 Family of products enables an

automatic forced recalibration when a touch persists

beyond a certain length of time. This optional feature

enables recalibration in the case that some material

remains on the sensor resulting in a continuous, but

unintended, touch signal.

The Stuck Touch Recalibration Register (0x053) sets

the time limit for a continous touch before a

recalibration is forced. When a recalibration occurs,

all active sensors are recalibrated. To ensure that a

lengthy, but real, touch does not result in

recalibration, it is generally advisable to set the

timer limit for stuck touch recalibration to be well

above the expected duration for a valid touch.

The actual time limit is a function of the # of

configured active sensors. For more detail on how to

set a specific stuck touch time limit, please refer to

the Detailed Register Document for the particular

device being used.

PROXIMITY SENSOR

The LDS6200 Family has built in proximity sesnsor

cabability. Each touch sensor can be enabled to act

as a proximity sensor by using register 0x039 bits 0-7,

but only one touch sensor can be used as a proximity

sensor. Register 0x046 bits 0-7 are used to check the

status of the proximity sensor. Increasing bits 10 – 15

of register 0x039 will increase the sensitivity of the

proximity channel. Sensitivity should be adjusted for

each application to achieve solid reliability. For more

information please see Application Note 62xxAN1.

TOUCH EVENT DURING POWER ON

When the device is first powered on the device will

automatically calibrate to adjust to external conditions

such as ambient temperature, humidity and smudges.

To indicate a touch event during power on, bit 0 of

register 0x038 will need to be enabled by setting to

‘1’. In order to be able to identify a touch event upon

power up SELC values must be predefined for each

active touch sensor using registers 0x030 – 0x037.

By setting a predefined SELC value a touch event

can still be recognized on power up without concern

of not having the touch event aknowledged since it

has been calibrated into the signal. For more

information please see Application Note 62xxAN1.

LDS6200 Family

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Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

TOUCH OPTIMIZATION

DEBOUNCE

The debounce feature enables a time criteria to be

set as an “acceptance” criteria for a touch being

recognized as valid. Because capactive touch inputs

frequently involve rigid overlays, there is no

compression or “give” associated with a touch. As a

result, a finger may very lightly “bounce” for a period

of time, resulting in a fluctuating capacitive effect on

the capacitive sensor. If the fluctuation results in

capacitance values varying above and below the

touch threshold level, multiple touches may be

erroneously reported to the host processor.

By setting a time criteria required for the capacitive

signal to remain above the threshold value, this type

of inadvertant multiple touch event may be eliminated.

The Debounce Registers (0x020 to 0x027) are used

for this purpose. Bits 0-8 set the # of

consecutive

scan cycles that the capacitive signal must remain

above the touch threshold value before a touch is

reported to the host. The LDS62xx family allows each

channel to set its debouce criteria independently of

the other channels.

The diagram above shows an example of fluctuating

capacitive signal and the debounce time that

eliminates multiple touch reporting.

HYSTERESIS

Hysteresis is another method of ensuring touch

stability. The hysteresis feature enables a “buffer

region” to be established within which the capacitive

value of an established touch may vary and still be

recognized as a continous touch. Hysteresis

Configuration Register 0x075 (bits 0-5) sets the

amount of capacitance variation (referenced from the

Touch Threshold level depicted in the diagram below)

that may be tolerated before the current touch is

reported as being removed from the sensor.

The diagram above shows a typical example of

hysteresis, which allows a certain amount of

capacitance variation to occur without multiple touch

events being reported to the host. In the above

diagram, the buffer region is defined by the area

below the Touch Threshold Level and above the

“UnTouch” Threshold level. This size of this region is

effectively specified by programming the amount of

capacitance variation allowed via the Hysteresis

Configuration Register value.

With hysteresis, the weaker capacitive signal

depicted by the two intermittent lines falling below the

original touch threshold are now considered a

continuation of the original touch since they remain

above the UnTouch threshold level.

Capacitance Value

Once Touched,

Remain

Touched Until Below

Debounce:

Min Time Criteria

for Valid Touch

Touch

Recognized

Debounce:

Min Time Criteria

for Valid Touch

Touch NOT

Recognized

Debounce:

Min Time Criteria

for Valid Touch

Debounce:

Min Time Criteria

for Valid Touch

Touch

Recognized

Touch

Recognized

Debounce:

Min Time Criteria

for Valid Touch

Touch NOT

Recognized

Debounce:

Min Time Criteria

for Valid Touch

Debounce:

Min Time Criteria

for Valid Touch

Touch NOT

Recognized

LDS6200 Family

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Characteristics subject to change without notice

CAPACITANCE-TO-DIGITAL

CONVERSION

The LDS6200 Family capacitance-to-digital converter

(CDC) utilizes a sigma-delta design for capacitive

sensing. Up to 8 sensor inputs are available to be

connected through a switch matrix to the CDC.

The nominal decimation (oversampling) rate is 1024,

which designates the number of samples acquired

per sensor input for each scan cycle. The decimation

process averages multiple samples from the CDC to

arrive at one optimized result. The process of

averaging multiple samples reduces the effect of

spurious noise that can adversely affect touch

detection.

The decimation rate may be programmed from the

nominal value of 1024 to alternate rates of 128, 256,

512, or 2048. Since the update time per sensor is

directly affected by the selected decimation rate, care

should be taken to assure that the proper balance is

achieved between system performance and touch

update rates. In the majority of cases, the default

decimation rate is optimal.

The conversion time per sensor input depends upon

the programmed decimation rate and the possible

options are shown in the table below:

Conversion Time/Input vs Decimation Rate (ms)

Decimation Rate (d)

128 256 512

1024

Conversion Time

0.256 0.512 1.024

2.048

Table 1: Conversion Time (in ms) per Input vs

Decimation Rate

The update rate (time between sequential scan

cycles) is the product of the single output CDC

conversion rate above multiplied by the number of

active sensors. For the highest channel LDS6200

offering, if all 8 sensor inputs are utilized, the

maximum possible update rate would be ~16ms.

LDS6200 Family

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Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

CDC SEQUENCER

Based upon the status of the sensor input

configuration above, the on-board sequencer will

proceed to sample all sensor-connected inputs and

convert the capacitance measurements to digital

capacitive value referenced off a baseline value.

Those configured as floating will not be connected to

the CDC for conversion.

The number of sensor inputs required for different

input types will depend upon the nature of input type.

A simple button input that registers only a touch/no-

touch situation (“0D”) requires only one input.

Position-variable inputs with more than just an on/off

designation (“1D” inputs such as sliders and scroll

wheels) require more than one input, with the

required number dependant upon the desired

resolution. For example, a coarse scroll wheel may

be implemented with only 4 sensor inputs, while a

higher resolution version might be implemented with

10 inputs. The LDS6200 Family of products includes

built-in 2x interpolation, meaning 2 times the number

of touch positions as physical elements can be

achieved (2 times # of elements minus 1 in case of

sliders). The location ID and direction are available

via status registers.

Figures 11 and 12 below show connection examples

of both a button/slider combination and a scroll wheel

implementation.

C

D

C

Figure 7: Button/Slider Connection Example

C

D

C

Figure 8: Scroll Wheel Connection Example

More detail on the configuration and usage of the

built-in slider/scroll functionality will be available

Application Note 61xxAN1: “LDS61xx Enhanced

Functionality Usage and Configuration”.

SIMPLE RETRIEVAL OF TOUCH RESULTS:

BUTTONS

The Interrupt Status Registers (0x043) contains the

Interrupt status of every sensor input. When the

relative magnitude of touch is not important and only

touch or no-touch status is required, the Interrupt

Status Register is sufficient for determining touch

status of buttons.

The INTB pin is designed to drive low when either a

valid touch or touch-termination (“untouch”) event

occurs. In this way, INTB provides notification to the

host processor that a touch-relevent event has

occurred and the Interrupt Status Registers have

been updated. By reading the Interrupt Status

Registers and determining which sensor input

interrupt bit is high, the system may determine which

sensor was touched or untouched. (Note: The

polarity of the INTB status pin may be configured at

power up to invert to drive high when a touch or

touch-termination event occurs).

The act of reading the Interrupt Status Register

resets the INTB pin back to the high state. When the

next touch-relevant event occurs, the process is

repeated, with the host processor being notified by

INTB driving low and subsequently reading the

Interrupt Status Registers to determine which sensor

inputs were touched or “untouched”.

LDS6200 Family

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Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

For “0D” or simple “on/off” (touch/untouch) inputs like

buttons, the results of the Interrupt Status Register

are sufficient to take action based on which touch

button was activated.

TOUCH RESULTS: SLIDERS AND SCROLL

Position-variable or “1D” inputs with more than an

on/off status require the host processor to read back

the conversion status results to properly interpret

touch location.

The LDS6200 Family offers built-in support for slider

and scroll wheels, enabling the user to assign which

sensor channels are utilized in slider or scroll input

types. Slider/Scroll Configuration register 0x074

allows up to 8 channels (C0-C7) to be assigned as

slider/scroll wheel elements. A separate slider/scroll

interrupt bit is available, as well as a direction bit and

5-bit location ID register, register 0x045 bits 0-4, to

directly read the current location being touched as

well as the direction of movement. Two times

interpolation is available to generate two times (two

times minus one for sliders) the number of reported

touch positions as actual touch elements to support

higher resolution requirements.

For more information on configuring slider and

scroll wheel setup and interpreting the results

registers, please see the Application Note

61xxAN1: “LDS61xx Enhanced Functionality

Usage and Configuration”.

Interpolation to achieve higher than 2x resolution

enhancement is possible by using host-side

algorithms to read the digital capacitance values and

interpolate beyond the 2x level. The degree of

interpolation achievable is a function of the sensor

size, shape, and overlay thickness. Contact your

local IDT contact for more information on >2x

interpolated slider and scroll implementations.

LDS6200 Family

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Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

OUTPUTS

GPIO OUTPUT

The GPIO pin may be disabled, configured as an

input to control the INTB output (details on usage of

GPIO as an input follow on page 38), or configured

as either a low or high output. The “GPIO

Configuration Register” (0x009) bits [1:0] are used for

this purpose. The default state for GPIO is the output

low state.

Use of the GPIO as an output can used to turn on

and off an LED if used with as the gate control of an

external transistor which supplies the LED drive

current.

INTERRUPT (INTB)

The INTB output notifies the host processor of an

interrupt event. Interrupt events are classified into

two categories: a sensor touch or untouch interrupt or

a GPIO input generated interrupt.

By default, the INTB pin is configured as an active-

low CMOS output, with no pull-up resistor necessary.

When an interrupt event occurs, the LDS6200 Family

pulls the INTB pin low to signal the host processor

that a touch-relevant event has occurred.

Once the interrupt signal is triggered, the host

processor may read the Interrupt Status Registers

(0x043) to determine which type of interrupt has

occurred (Bit 15 of 0x043 for GPIO input generated

interrupt, other bits for touch generated interrupts). In

the case of a touch or untouch event, a touch (finger

down) will result in a “1” in the associated sensor

register bit, while an untouch (finger up) will result in

a “0”.

The Interrupt Status Registers and the INTB pin itself

are reset once the host completes a read operation,

enabling the next interrupt event to be sensed and

communicated.

Touch and Untouch Interrupts

As mentioned in the above section, two interrupt

events will be registered once a touch occurs: the

first when contact is made with the capacitive sensor

(finger down or “touch”), and again when contact is

terminated (finger up or “untouch”). The figure below

illustrates this.

Figure 9: Sensor Activation Interrupt Example

The second interrupt notifies the host that the touch

stimulus is no longer in contact with the sensor.

In order for the second interrupt to be properly

differentiated from the first, the host should read back

the Interrupt Status Registers when INTB is first

pulled low to enable the INTB pin to return to its high

state and be re-triggered when the untouch event

occurs.

SHIELD

In the default device configuration, the SHIELD pin

outputs the identical excitation waveform as that used

on the actively read sensor input. In this

configuration, SHIELD may effectively be utilized to

reduce stray capacitance to ground that has the

potential to affect the capacitance-to-digital

conversion process.

By shielding both a) the connection traces between

sensor array and LDS6200 Family sensor inputs and

b) the shield plane around the sensor array elements

themselves, stray capacitance is significantly reduced.

Interactions between adjacent connection traces and

between closely spaced sensor array elements are

also reduced and longer distances between sensor

array and LDS6200 Family may be supported while

still achieving a high level of touch performance.

Please refer to AN5: Preliminary Use of SHIELD

application note for more guidance on use of the

SHIELD pin.

LDS6200 Family

29

Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

GPIO AS INPUT TO INTERRUPT SIGNAL

The GPIO pin may also be configured as an input to

control the interrupt output INTB by programming the

bits [1:0] in the “GPIO Configuration Register”

(0x009) to [0,1]. When using GPIO as an input, INTB

can be triggered on a low level, high level, falling

edge, rising edge, or on both falling and rising edges

of the GPIO pin. The GPIO Input Configuration bits

(bits [4:2] of register 0x009) determine which stimuli

type will trigger INTB. Figures 14-18 illustrate the

various types of input triggers.

The GPIO status bit in the second Interrupt Status

Register (Bit 15 of register 0x043) indicates that the

GPIO trigger condition occurred. After a host reads

this status register, the GPIO status bit and INTB

signal are cleared (assuming the original triggering

condition is no longer present) and no touch events

are otherwise causing INTB to remain low.

Register 0x009

Bits [4:2] Input Stimuli Type

000

Not used (Default)

001 Low level trigger

010 High level trigger

011/100 Not used

101 Falling edge trigger

110 Rising edge trigger

111 Both edge trigger

Table 3: GPIO Interrupt Configuration

Figure 10: GPIO Low Level Trigger

(GPIO Input Cfg = ”001”)

Figure 11: GPIO High Level Trigger

(GPIO Input Cfg = “010”)

Figure 12: GPIO Falling Edge Trigger

(GPIO Input Cfg = ”101”)

Figure 13: GPIO Rising Edge Trigger

(GPIO Input Cfg = ”110”)

Figure 14: GPIO Both (Falling/Rising) Edge Trigger

(GPIO Input Cfg = ”111”)

LDS6200 Family

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Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

PACKAGE DRAWING AND DIMENSIONS

16-PIN TQFN, 3mm x 3mm, 0.5mm PITCH

LDS6200 Family

31

Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

PACKAGE DRAWING AND DIMENSIONS

16-PIN SOIC, 3.9mm x 9.9mm, 1.27mm PITCH

LDS6200 Family

32

Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

PACKAGE DRAWING AND DIMENSIONS

20-PIN TQFN, 3mm x 3mm, 0.4mm PITCH

PACKAGE DRAWING AND DIMENSIONS

LDS6200 Family

33

Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

20-PIN SOIC, 7.5mm x 12.8mm, 1.27mm PITCH

LDS6200 Family

34

Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

ORDERING INFORMATION

Part Number* Package Package Marking

LDS6201NTGI8 TQFN-16 3mm x 3mm

(1)

NTG

LDS6201DCGI8 SOIC-16 3.9mm X 9.9mm

(1)

DCG

LDS6202NTGI8 TQFN-16 3mm x 3mm

(1)

NTG

LDS6202DCGI8 SOIC-16 3.9mm X 9.9mm

(1)

DCG

LDS6203NTGI8 TQFN-20 3mm x 3mm

(1)

NTG

LDS6203SOGI8 SOIC-20 7.5mm X 12.8mm

(1)

SOG

LDS6204NTGI8 TQFN-20 3mm x 3mm

(1)

NTG

LDS6204SOGI8 SOIC-20 7.5mm X 12.8mm

(1)

SOG

Notes (*Remove the “8” at the end of the part number for non-T/R option):

1. Matte-Tin Plated Finish (RoHS-compliant)

2. Quantity per reel is 2500 for TQFN package and 1500 for SOIC package

EXAMPLE OF ORDERING INFORMATION

PL Indicator Package Code

NTG = TQFN

DCG = SOIC

SOG = SOIC

Prefix Device # Suffix

LDS 62

0x

NT

G

I8

Product Number

(see Product

Family Guide on

Page 1)

Temperature Range and Packing

Option

Temperature Range: I = Industrial

(-40C to 80C)

Packing Option: 8 = Tape & Reel

LDS6200 Family

35

Doc. No. 6200 FamilyDS, Rev. 0.5

Characteristics subject to change without notice

REVISION LOG

Date Rev. Reason

01/13/10 0.0 Initial Draft

04/09/10 0.1 Block diagram correction

05/06/10 0.2 Figure 11 and 12 update

06/25/10 0.3 Removed SSOP package and included SOIC package

11/10/10 0.4 Updated pinout diagrams to indicate TEST0 and TEST1 pins. Clarify

connection requirements for TEST0 and TEST1 pins.

6/1/11 0.5 Updated 16ld TQFN package dimenions on page 30. Updated I2C read

timing diagram

DISCLAIMER Integrated Device Technology , Inc. (IDT) and its subsidiaries reserve the right to modify the products and/or specifications

described herein at any time and at IDT’s sole discretion. All information in this document, including descriptions of product features

and performance, is subject to change without notice. Performance specifications and the operating parameters of the described products are

determined in the independent state and are not guaranteed to perform the same way when installed in customer products. The

information contained herein is provided without representation or warranty of any kind, whether express or implied, including, but not limited

to, the suitability of IDT’s products for any particular purpose, an implied warranty of merchantability, or non-infringement of

the intellectual property rights of others. This document is presented only as a guide and does not convey any license under intellectual

property rights of IDT or any third parties.

IDT’s products are not intended for use in life support systems or similar devices where the failure or malfunction of an IDT product can be

reasonably expected to significantly affect the health or safety of users. Anyone using an IDT product in such a manner does so at

their own risk, absent an express, written agreement by IDT.

Integrated Device Technology, IDT and the IDT logo are registered trademarks of IDT. Other trademarks and service marks used herein,

including protected names, logos and designs, are the property of IDT or their respective third party owners.

6024 Silver Creek Valley Road Document No: 6200 Family DS

San Jose, California 95138 Revision: 0.5

http://

www.idt.com

Issue date:

6/

30

/11

LDS6100 Family