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lds6200 family ? 2011 idt 1 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, allowi ng 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 gener al 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 inp ut *** 1.8v, excluding vddio current, which varies wit h vddio voltage, i/f type, and communication freque ncy
lds6200 family ? 2011 idt 2 doc. no. 6200 familyds, rev. 0.5 characteristics subject to change without notice typical application circuit for dual supply voltage s 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 resetb resetb 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 ? 2011 idt 3 doc. no. 6200 familyds, rev. 0.5 characteristics subject to change without notice typical application circuit for single supply volta ge 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 resetb resetb rpu vdd vss vddio* (1.65v~5.5v) c1, c2 > 1uf *for voltages >1.95v, apply voltage to vddio and ti e 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 ? 2011 idt 4 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 = 1.5k 8 8000 v charge device model charging resistor = 300m 8 1500 v machine model c = 200pf, r = 0 8 400 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 an d tie vdd pin to gnd through c1 typical application circuit shown on page 3
lds6200 family ? 2011 idt 5 doc. no. 6200 familyds, rev. 0.5 characteristics subject to change without notice electrical operating characteristics vdd = 1.8v, vddio = 1.8v t amb = -40c to +85c unless otherwise specified parameter symbol conditions related pins min typ ma x 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*vd dio v low level output voltage vol iol= +1ma (*2) 0.2*v ddio 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, s et ldoen to logic high, and tie vdd1 pin to gnd thr ough 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 de pending upon system conditions ? contact idt for exception conditions
lds6200 family ? 2011 idt 6 doc. no. 6200 familyds, rev. 0.5 characteristics subject to change without notice electrical operating characteristics (current consu mption) vdd = 1.8v, vddio = 1.8v, t amb = -40c to 85c unless otherwise specified parameter symbol conditions related pins min typ ma x unit current consumption full power mode iddfp 55 100 ua sleep mode iddsl 17 ua shutdown, t amb = 25c iddsd t amb = 25c 0.5 5 ua shutdown iddsd t amb = -40c to +85c 10 ua
lds6200 family ? 2011 idt 7 doc. no. 6200 familyds, rev. 0.5 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 a mbient 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 s start condition hold time t slw 1.3 s clock low period t shw 0.6 s clock high period t su:dat 100 ns data setup time t hd:dat 0 ns data hold time t su:sto 0.6 s stop condition setup time t su:sta 0.6 s start condition setup time t buf 1.3 s 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 s data valid time t vd:ack 0.9 s data valid acknowledge time figure 3: i 2 c-compatible detailed timing diagram
lds6200 family ? 2011 idt 8 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 f rom high-to-low while keeping sclk high, followed by the 7-bit devi ce address plus a read/write bit dictating the dire ction of data transfer (read=1, write=0) . data is sent over a series of 9 clock pulses mad e 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 re sets its address pointer to 0x000 and the serial in terface pins enter the idle state. data must be transition ed when the clock signal is low and remain stable w hen 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 tw o data bytes containing the 10-bit register address to be writte n. the upper and lower register address bits are s hown below: msb lsb 7 6 5 4 3 2 1 0 x x x x x x 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 intern al register pointed to by the 10-bit register address. figure 4: i 2 c-compatible register write the lds6200 family automatically increments the add ress pointer enabling sequential writes to register s 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 ? 2011 idt 9 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 fam ily. the device address (0101 100) and read/write bit (0 for initial write of starting address) is sent over th e bus, followed by two data bytes that contain the 10-bit register add ress to be read. the address format is identical t o that used during write operations, with only the 10 lower bit s of the 16-bit address word containing address inf ormation. the master then either ends the write operation wit h 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 in crements 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 co ntinues to attempt to read from the part, the lds62 00 family continues to send data from the last register that was addressed.
lds6200 family ? 2011 idt 10 doc. no. 6200 familyds, rev. 0.5 characteristics subject to change without notice device pinouts (qfn) lds6201ntgi test1 resetb vss ldoen vddio test0 intb shield
lds6200 family ? 2011 idt 11 doc. no. 6200 familyds, rev. 0.5 characteristics subject to change without notice lds6202ntgi 12 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 ? 2011 idt 12 doc. no. 6200 familyds, rev. 0.5 characteristics subject to change without notice lds6203ntgi 12 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 ? 2011 idt 13 doc. no. 6200 familyds, rev. 0.5 characteristics subject to change without notice LDS6204ntgi 12 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 ? 2011 idt 14 doc. no. 6200 familyds, rev. 0.5 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 23 4 5 67 8 16 15 14 13 12 11 10 9 ldoen
lds6200 family ? 2011 idt 15 doc. no. 6200 familyds, rev. 0.5 characteristics subject to change without notice lds6202dcgi vss test0 c3 vdd test1 c1 c0 shield sclk intb gpio sda resetb vddio c2 1 23 4 5 67 8 16 15 14 13 12 11 10 9 ldoen
lds6200 family ? 2011 idt 16 doc. no. 6200 familyds, rev. 0.5 characteristics subject to change without notice lds6203sogi test0 n.c. n.c. c0 c1 c4 c3 c2 gpio sda test1 resetb intb ldoen c5 1 23 4 5 67 8 9 10 20 19 18 17 16 15 14 13 12 11 shield sclk vdd vss vddio
lds6200 family ? 2011 idt 17 doc. no. 6200 familyds, rev. 0.5 characteristics subject to change without notice LDS6204sogi test0 c7 c6 c0 c1 c4 c3 c2 gpio sda test1 resetb intb ldoen c5 1 23 4 5 67 8 9 10 20 19 18 17 16 15 14 13 12 11 shield sclk vdd vss vddio
lds6200 family ? 2011 idt 18 doc. no. 6200 familyds, rev. 0.5 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 pi n) (?1? = ldo enable, supply voltage applied to vddio) vddio touch sensor supply voltage (>1.95v, ldo enab led) 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/plan e 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 ? 2011 idt 19 doc. no. 6200 familyds, rev. 0.5 characteristics subject to change without notice functional block diagram switch matrix figure 6: lds6200 family functional block di agram
lds6200 family ? 2011 idt 20 doc. no. 6200 familyds, rev. 0.5 characteristics subject to change without notice theory of operation the lds6200 puretouch ? family of capacitive touch controllers feature a highly-accurate capacitance-t o- digital converter (cdc) for touch button, slider, a nd 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 occurre d. 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 accurat e 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 locat ion and direction automatically calculated for slider a nd 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 an d overall touch characteristics. an interrupt output, intb, is available to notify t he host when a touch event has occurred. a gpio is also available to act as an input to control the in tb 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 sens or detection occurs continuously at very low power levels, eliminating the need for sleep periods between detection cycles that result in touch laten cy 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 wit h vddio voltage, i/f type, and communication frequency
lds6200 family ? 2011 idt 21 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 input s need to be fully active and always responsive to touch inputs. due to its ultra-low touch sensor po wer 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 l ow 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) execute s a soft reset of the device by initiating a new calibration cycle and resetting the state machine, including the interrupt status register. previousl y 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 th e 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 ini tial calibration. please contact your idt representativ e if start-up time optimization is required. power-up/initialization sequence the power up and initialization sequence involves t he following flow: power-up cold reset command initialize configuration registers software reset command initialization of the configuration registers is re quired to define the functionality of each channel, set to uch sensitivity levels, and generally specify the desir ed configuration of the highly flexible lds6200 family touch controller. the cold reset and software rese t commands are required to ensure consistency of operation before and after the initialization proce ss 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 vali d touch events. the calibration algorithm is execute d after every conversion cycle, ensuring that even rapidly changing ambient conditions are well compensated. *** 1.8v, excluding vddio current, which varies wit h vddio voltage, i/f type, and communication frequency
lds6200 family ? 2011 idt 22 doc. no. 6200 familyds, rev. 0.5 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?, lo w power mode is activated and the touch controller wi ll 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 slee p period time inserted between full power scan cycles . the full power scan cycle time is equal to ~2ms x t he number of active sensors. for example, 10 active sensors would result in a full power scan cycle tim e of ~20ms. the amount of sleep time inserted occurs in 1ms increments by setting the sleep configuration register (0x056) to the # of milliseconds desired f or 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 activ e 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 curr ent is relatively minor. accordingly, the system desig ner should take into consideration the # of active sens ors 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 br ief 100ms of sleep. adding an additional 150ms of slee p (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 wit h vddio voltage, i/f type, and communication frequency
lds6200 family ? 2011 idt 23 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 v alue. similarly, two strongest absolute touches mode only registers the two strongest touch events at an y given time, as judged by absolute capacitance value s. 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 leve l? for each sensor) is considered the strongest relati ve touch (and largest two deltas considered the two strongest relative touches). where sensor sizes (a nd therefore the resulting capacitance values resultin g from a touch) are significantly different, these tw o 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 stronges t 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 w ith 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 tou ch 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 persist s beyond a certain length of time. this optional fea ture enables recalibration in the case that some materia l remains on the sensor resulting in a continuous, bu t 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 occu rs, 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 wel l 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 proximit y sensor. register 0x046 bits 0-7 are used to check t he status of the proximity sensor. increasing bits 10 ? 15 of register 0x039 will increase the sensitivity of the proximity channel. sensitivity should be adjusted f or 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 condi tions 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 t o ?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 ? 2011 idt 24 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 input s 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 pe riod of time, resulting in a fluctuating capacitive effe ct 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 capacit ive signal to remain above the threshold value, this ty pe of inadvertant multiple touch event may be eliminat ed. 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 eac h channel to set its debouce criteria independently o f 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 ?buffe r region? to be established within which the capaciti ve 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 th e 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 tou ch 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 regio n 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 belo w the original touch threshold are now considered a continuation of the original touch since they remai n 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 ? 2011 idt 25 doc. no. 6200 familyds, rev. 0.5 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 decimati on 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, 25 6, 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 i s achieved between system performance and touch update rates. in the majority of cases, the defaul t 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 ? 2011 idt 26 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 ty pe. a simple button input that registers only a touch/n o- 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 numb er 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 availa ble via status registers. figures 11 and 12 below show connection examples of both a button/slider combination and a scroll wh eel implementation. figure 7: button/slider connection example figure 8: scroll wheel connection example more detail on the configuration and usage of the built-in slider/scroll functionality will be availa ble 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 on ly 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 whi ch sensor was touched or untouched. (note: the polarity of the intb status pin may be configured a t 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 t he 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 senso r inputs were touched or ?untouched?.
lds6200 family ? 2011 idt 27 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 regist er 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 ba ck the conversion status results to properly interpret touch location. the lds6200 family offers built-in support for slid er and scroll wheels, enabling the user to assign whic h sensor channels are utilized in slider or scroll in put types. slider/scroll configuration register 0x074 allows up to 8 channels (c0-c7) to be assigned as slider/scroll wheel elements. a separate slider/sc roll 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 (t wo 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 a nd interpolate beyond the 2x level. the degree of interpolation achievable is a function of the senso r size, shape, and overlay thickness. contact your local idt contact for more information on >2x interpolated slider and scroll implementations.
lds6200 family ? 2011 idt 28 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 ou tput 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 i nto 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 interrupt s). in the case of a touch or untouch event, a touch (fing er down) will result in a ?1? in the associated sensor register bit, while an untouch (finger up) will res ult in a ?0?. the interrupt status registers and the intb pin its elf 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 sens or (finger down or ?touch?), and again when contact is terminated (finger up or ?untouch?). the figure be low illustrates this. figure 9: sensor activation interrupt example the second interrupt notifies the host that the tou ch 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 u sed on the actively read sensor input. in this configuration, shield may effectively be utilized t o 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 element s themselves, stray capacitance is significantly redu ced. 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 ? 2011 idt 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 th e bits [1:0] in the ?gpio configuration register? (0x009) to [0,1]. when using gpio as an input, int b can be triggered on a low level, high level, fallin g edge, rising edge, or on both falling and rising ed ges of the gpio pin. the gpio input configuration bits (bits [4:2] of register 0x009) determine which stim uli type will trigger intb. figures 14-18 illustrate t he 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 read s this status register, the gpio status bit and intb signal are cleared (assuming the original triggerin g 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 ? 2011 idt 30 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 ? 2011 idt 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 ? 2011 idt 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 ? 2011 idt 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 ? 2011 idt 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 numbe r for non-t/r option): 1. matte-tin plated finish (rohs-compliant) 2. quantity per reel is 2500 for tqfn package and 1 500 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 ? 2011 idt 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 te st0 and test1 pins. clarify connection requirements for test0 and test1 pins. 6/1/11 0.5 updated 16ld tqfn package dimenions on p age 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 disc retion. all information in this document, including descriptions of product features and performance, is subject to change without notic e. performance specifications and the operating par ameters of the described products are determined in the independent state and are not gua ranteed to perform the same way when installed in c ustomer products. the information contained herein is provided without re presentation or warranty of any kind, whether expre ss or implied, including, but not limited to, the suitability of idt?s products for any parti cular purpose, an implied warranty of merchantabili ty, or non-infringement of the intellectual property rights of others. this do cument is presented only as a guide and does not co nvey any license under intellectual property rights of idt or any third parties. idt?s products are not intended for use in life sup port systems or similar devices where the failure o r malfunction of an idt product can be reasonably expected to significantly affect the hea lth or safety of users. anyone using an idt product in such a manner does so at their own risk, absent an express, written agreemen t 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 t he 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

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