SC614DB

SC614 SEMTECH | Alldatasheet

Document overview

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Technical content

Features

‹ Four independent current sinks for main backlight, adjustable from 0.4mA to 32mA each ‹ Dedicated MDIM pin for PWM dimming of main backlight ‹ Three independent current sinks for sub-backlight or flash, adjustable from 0.4mA to 102mA each ‹ Configurable sub-backlight or flash sinks ‹ Dedicated SDIM pin for PWM dimming of sub- backlight ‹ Dedicated FL pin for flash control ‹ Current accuracy to within ±1.5% down to 4.8mA ‹ Current matching to within ±0.5% down to 4.8mA ‹ Very high efficiency over 90% of battery life ‹ Shutdown current 0.1 μA (typ) ‹ Three charge pump operating modes: 1x, 1.5x, and 2x ‹ I 2C serial interface ‹ Soft-start/in-rush current limiting ‹ 1.33MHz and 250kHz programmable fixed frequency options ‹ Short-circuit/thermal protection ‹ Output open circuit protection ‹ MLPQ-24 package (4mm x 4mm), fully WEEE and RoHS compliant ‹ Cellular phone backlighting and flash ‹ LCD modules ‹ PDA backlighting and flash ‹ RGB LED Driver The SC614 is a high efficiency charge pump LED driver using Semtech’s proprietary mAhXLife TM technology. Performance is optimized for use in Li-ion battery applications. Each of 7 LED currents can be programmed via the I 2C serial control bus. M1 through M4 are for LED backlighting of LCD main displays. S1/FL3 through S3/FL1 can be used for backlighting sub displays and/ or for driving flash LEDs. These three current sinks are configurable over the I 2C interface for any combination of pins for sub or flash use. The charge pump automatically selects an operating mode based on the number of active loads, input voltage, and load currents required. Any combination of LED drivers can be enabled at one time, allowing the SC614 to power any combination of backlight and flash required by the application. Two dedicated pins, MDIM and SDIM, are provided to allow PWM dimming of the main and sub-backlights and one dedicated pin, FL, allows direct control of the flash. All three pins can be utilized without having to use the I 2C interface once the registers are set up. The enable pin can be used to put the device in low-current shutdown mode drawing 0.1μA (typ), or a reg- ister can be written that sets the device in a sleep mode that reduces the current to 50 μA (typ).

Description

434mA Max (500ms) LED LED LED LED32mA Max 32mA Max 32mA Max 32mA Max 306mA Max. 2u2 C3 1u C4 1u VIN11 VIN17 EN2 SDA7 SCL8 ASEL5 SDIM3 MDIM4 FL6 VOUT 9 VOUT 16 M1 1 M2 24 M3 23 M4 22 S1/FL3 20 S2/FL2 19 S3/FL1 18 GND12 GND21 TPAD C1+10 C1-13 C2+15 C2-14 SC614 EN SDA SCL SDIM FL MDIM 328mA Max Continuous VBAT Pull-up Pull-up VLOGIC Note: R1 and R2 pull-up resistors are a requirement of the I2C specification MAIN BACKLIGHT FLASH Typical Application Circuit

Applications

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com Absolute Maximum Ratings

Electrical Characteristics

retemaraPl obmySm umixaMs tinU egatloVylppuSV NI 5.6ot3.0-V egatloVtuptuOV TUO 5.6ot3.0-V +2C,+1C-egatloVniP Vot3.0- TUO 3.0+V sniprehtollA-egatloVniP Vot3.0- NI 3.0+V V TUO noitaruDtiucriCtrohSt CS etinifednIs tneibmAotnoitcnuJ,ecnatsiseRlamrehT )1( θ AJ 04° W /C egnaRerutarepmeTtneibmAgnitarepOT A 58+ot04-° C egnaRerutarepmeTnoitcnuJT J 051+ot04-° C egnaRerutarepmeTegarotST GTS 051+ot56-° C s03ots01)gniredloS(wolfeRRIT DAEL 062° C )ledoMydoBnamuH(gnitaRDSE )2( V DSE 2V k retemaraPl obmySs noitidnoCn iMp yTx aMs tinU snoitacificepSlacirtcelEpmuPegrahC egatloVylppuStupnIV NI 0.35 .5V latoTmumixaM tnerruCtuptuO I )XAM(TUO VNI ,stnerrucDELevitcallafomus,V4.3> V )XAM(TUO .xamsm005,V2.4= 434A m tnerruCDELlaudividnI thgilkcaBniaM,gnitteS I xM sgnitteSlanimoN4 .02 3A m tnerruCDELlaudividnI hsalF/buS,gnitteS I yLF/xS sgnitteSlanimoN4 .02 01A m DELlaudividnI ycaruccAtnerruC I CCA_DEL VNI I,V7.3= TES Am4.0=0 3±A μ VNI I,V7.3= TES Am02=0 .8-5 .1±0 .8+% V,ylnosniphsalF NI I,V7.3= TES Am201=2 ±% gnihctaMDEL )1( I DEL-DEL VNI I,V7.3= TES Am4.0=0 2±A μ VNI I,V7.3= TES Am02=5 .3-5 .0±5 .3+% V,ylnosniphsalF NI I,V7.3= TES Am201=1 ± Exceeding the specifications below may result in permanent damage to the device or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied. Exposure to Absolute Maximum rated conditions for extended periods of time may affect device reliability. Notes: (1) Calculated from package in still air, mounted to a 3” x 4.5”, 4-layer FR4 PCB with thermal vias under the exposed pad per J ESD51 standards. (2) Tested according to JEDEC standard JESD22-A114-B.

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com POWER MANAGEMENT Electrical Characteristics (Cont.) retemaraPl obmySs noitidnoCn iMp yTx aMs tinU ).tnoC(snoitacificepSlacirtcelEpmuPegrahC edoMx5.1otedoMx1 egatloVnoitisnarTgnillaF V x1SNART I TUO V,)DEL/Am01(Am07= TUO V4=7 0.4V edoMx1otedoMx5.1 siseretsyH V x1TSYH I TUO V,)DEL/Am01(Am07= TUO V4=0 01V m edoMx2otedoMx5.1 egatloVnoitisnarTgnillaF V x5.1SNART I TUO V,)DEL/Am01(Am07= TUO V4=2 9.2V edoMx5.1otedoMx2 siseretsyH V x5.1TSYH I TUO V,)DEL/Am01(Am07= TUO V4=0 02V m tnerruCnwodtuhSI )FFO(Q V,DNG=NE NI T,V2.4= A C°52=1 .00 .1 Aμ V,DNG=NE NI T,V2.4= A C°58+otC°04-=2 1 )2( tnerruCtnecseiuQlatoTI Q V=NE(peelS NI ,1=PEELS, )ytivitcaecafretnilaireson 05 )3( Aμ I,edomx1 TUO Am8.0=0 0.15 8.1A m I,edomx5.1 TUO f,Am8.0= PMUP zHk052=4 .1 I,edomx2 TUO f,Am8.0= PMUP zHk052=8 .10 .3 I,edomx5.1 TUO f,Am8.0= PMUP zHM33.1=3 .2 I,edomx2 TUO f,Am8.0= PMUP zHM33.1=5 .32 .5 etatS-ffOkniStnerruC tnerruCegakaeL I )FFO(DEL VNI V= NE V= DEL V2.4=1 .01 A μ eziSpetStnerruCCADI PSCAD retsigertib-84 .0A m ytiraeniL-noNlaitnereffiDL ND1 ±B SL ycneuqerFpmuPf PMUP VNI 0=LESF,V2.3=0 52z Hk VNI 1=LESF,V2.3=3 3.1z HM )MIDS,MIDM,LF,NE,LESA(snoitacificepSlacirtcelEO/IlatigiD dlohserhThgiHtupnIV HI VNI V5.5=6 .1V dlohserhTwoLtupnIV LI VNI V3=4 .0V tnerruChgiHtupnII HI VNI V5.5=0 1A μ tnerruCwoLtupnII LI VNI V5.5=0 1A μ ycneuqerFtupnImumixaM )sniPMIDSdnaMIDM( f MID 01 z Hk tupnImumixaM )niPLF(ycneuqerF f LF elcycytud%050 1 z Hk

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com Electrical Characteristics (Cont.) retemaraPl obmySs noitidnoCn iMp yTx aMs tinU I2 snoitacificepSsuBecafretnIC egatloVtupnIlatigiDV LI-B LCSdnaADS4 .0V V HI-B LCSdnaADS6 .1 egdelwonkcAADS egatloVtuptuO V LO VNI I,V3= )ADS(NI-B Am3=4 .0V tnerruCtupnIlatigiDI NI-B 2.0-2 .0A μ ecnaticapaCniPO/IC NI 01F p I2 snoitacificepSgnimiTC ycneuqerFkcolCf LCS 0040 44z Hk doirePwoLLCS )2( t WOL 3.1s μ doirePhgiHLCS )2( t HGIH 6.0s μ emiTdloHataD )2( t TAD;DH 0s μ emiTputeSataD )2( t TAD;US 001s n emiTpu-tratSecafretnI )2( t NE hgihdellupsiNEretfaemitpu-tratssuB0 53s μ detaepeRrofemiTputeS noitidnoCtratS )2( t ATS;US 6.0s μ detaepeRrofemiTdloH noitidnoCtratS )2( t ATS;DH 6.0s μ potSrofemiTputeS noitidnoC )2( t OTS;US 6.0s μ neewteBemiTeerFsuB TRATSdnaPOTS )2( t FUB 3.1s μ noitcetorPtluaF tiucriCtrohStuptuO timiLtnerruC I )CS(TUO V TUO DNG=0 03A m erutarepmeTrevO )4( T PTO )C°01=siseretsyh(dlohserhtgnisiR0 61C ° egatloVrevOtuptuOV PVO 7.5V Notes: (1) LED matching applies to current sinks set to the same current only. Matching is calculated as follows: ( ) () %100II III MINMAX MINMAX LEDLED •+ −±=− (2) Guaranteed by design. (3) The total quiescent current in Sleep Mode will increase when serial bus activity occurs, and with the clock frequency of th at bus activity. (4) When the junction temperature exceeds the Over Temperature (OT) threshold, the device will enter Sleep Mode with the conten ts of all registers retained. The device will exit Sleep Mode and re-commence normal operation as soon as the junction temperature drops by more than the OT hysteresis.

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com POWER MANAGEMENT Block Diagram mAhXLifeTM Fractional Charge Pump (1x, 1.5x, 2x) Oscillator Digital Interface and Logic Control Current Setting DAC VIN EN SDA SCL VOUT C1+ C1- C2+ C2- FL Control Override MDIM SDIM VIN VOUT ASEL Pull high or low to set slave address 10 13 15 14 S1/FL3 S2/FL2 S3/FL1 GND GND

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com Pin Configuration eciveDe gakcaP TRTLM416CS )1( 42-QPLM )2( BD416CS )3( draoBnoitartsnomeD BVE416CS )4( draoBnoitaulavE Notes: (1) Lead free product. This product is fully WEEE and RoHS compliant. (2) Only available in tape and reel packaging. A reel contains 3000 devices. (3) The demonstration board showcases the most common uses for this part, running at maximum current settings. (4) The evaluation board is user-configurable and allows the user to communicate with the part using a graphical user interface on a personal computer with a USB connection. Contact factory for availability. Marking Information 614 yyww yy = two-digit year of manufacture ww = two-digit week of manufacture xxxxx = lot number Top Mark xxxxx xxxxx MLP24: 4X4 24 LEAD TOP VIEW 7 8 9 10 11 12 24 23 22 21 20 19 T EN SDIM MDIM ASEL FL S3/FL1 VIN VOUT C2+ C2- C1- GND S1/FL3 S2/FL2 SDA SCL VOUT C1+ VIN GND

Ordering Information

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com POWER MANAGEMENT Pin Descriptions #niPe maNniPn oitcnuFniP 11 M .desutonfidetcennocnuevaeL.1DELthgilkcabniamroftupniknistnerruC 2N E. hgihevitca,tupnielbanE 3M IDS. NO=wol,FFO=hgiH.sDELthgilkcabbusrofnipgnimmiD 4M IDM. NO=wol,FFO=hgiH.sDELthgilkcabniamrofnipgnimmiD 5L ESA owtswollasihT.sserddaecivedehtnitibenotesothgihrowoldellupebnacniP.tcelessserddA .subemasehtotdetcennocebotsecived 6L F. FFO=wol,NO=hgiH.sDELhsalfrofniplortnoC 7A DSI 2 .deriuqersirotsiserpu-lluplanretxenA.)lanoitcerid-ib(atadlairesC 8L CSI 2 .deriuqersirotsiserpu-lluplanretxenA.tupnikcolcC 9T UOV. 61nipottcennoC.tuptuopmupegrahC 01+ 1C. noitcennocevitisop1CroticapactekcuB 11N IV. 71nipottcennoC.tupniegatlovyrettaB 21D NG. enalpdnuorgotyltceridtcennoC.nipdnuorG 31- 1C. noitcennocevitagen1CroticapactekcuB 41- 2C. noitcennocevitagen2CroticapactekcuB 51+ 2C. noitcennocevitisop2CroticapactekcuB 61T UOV TUOVllA.12nipotroticapaccimarecFμ1agnisunipsihtelpuoceD.tuptuopmupegrahC .roticapacsihtfopotehtotderratsebdluohssnoitcennoc 71N IV .12nipotroticapaccimarecFμ2.2agnisunipsihtelpuoceD.tupniegatlovyrettaB 811 LF/3S hsalfmumixamrof3LF/1Sdna2LF/2ShtiwenibmoC.hsalfrothgilkcabbusroftupniknistnerruC .desutonfidetcennocnuevaeL.ytilibapactnerruc 912 LF/2S hsalfmumixamrof1LF/3Sdna3LF/1ShtiwenibmoC.hsalfrothgilkcabbusroftupniknistnerruC .desutonfidetcennocnuevaeL.ytilibapactnerruc 023 LF/1S hsalfmumixamrof1LF/3Sdna2LF/2ShtiwenibmoC.hsalfrothgilkcabbusroftupniknistnerruC .desutonfidetcennocnuevaeL.ytilibapactnerruc 12D NG. enalpdnuorgotyltceridtcennoC.nipdnuorG 224 M .desutonfidetcennocnuevaeL.4DELthgilkcabniamroftupniknistnerruC 323 M .desutonfidetcennocnuevaeL.3DELthgilkcabniamroftupniknistnerruC 422 M .desutonfidetcennocnuevaeL.2DELthgilkcabniamroftupniknistnerruC -L AMREHT DAP detcennoctoN.saivelpitlumgnisuenalpdnuorgottcennoC.sesoprupgniknistaehrofdaP .yllanretni

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com Register Map Note: all registers are readable and writable. Definition Of Terms: 0: Leave this bit as a 0. xEN: On/off control for individual current sinks. Set to 1 to enable, clear to 0 to disable. FLMODE: Flash Mode control bit. Set to 1 for Flash mode, clear to 0 for normal mode. SLEEP: Sleep Mode control bit. Set to 1 to put into low current mode (Bandgap, UVLO monitor and interface monitoring stay on, all other circuitry shut down), clear to 0 for normal mode. SWRES: Software Reset bit. Set to 1 to reset all registers (SWRES clears automatically and does not require an additional I2C write). FSEL: Frequency Select bit. Allows the choice between two different switching frequencies, set to 1 for 1.33MHz, clear to 0 for 250kHz. sserddA7 D6 D5 D4 D3 D2 D1 D0 Dt eseR eulaV noitpircseD 00x0 0N E1LF/3SN E2LF/2SN E3LF/1SN E4MN E3MN E2MN E1M0 0x0f fO/nODEL lortnoc 10x0 0 Am23=05x0,FFO=00x0,tib/Am4.0,gnittestnerructib-7 00x0t nerruc1M lortnoc 20x0 0 Am23=05x0,FFO=00x0,tib/Am4.0,gnittestnerructib-7 00x0t nerruc2M lortnoc 30x0 0 Am23=05x0,FFO=00x0,tib/Am4.0,gnittestnerructib-7 00x0t nerruc3M lortnoc 40x0 0 Am23=05x0,FFO=00x0,tib/Am4.0,gnittestnerructib-7 00x0t nerruc4M lortnoc 50x0 Am201=FFx0,FFO=00x0,tib/Am4.0,gnittestnerructib-8 00x03 LF/1S lortnoctnerruc 60x0 Am201=FFx0,FFO=00x0,tib/Am4.0,gnittestnerructib-8 00x02 LF/2S lortnoctnerruc 70x0 Am201=FFx0,FFO=00x0,tib/Am4.0,gnittestnerructib-8 00x01 LF/3S lortnoctnerruc 80x0 0E DOMLFP EELSS ERWSL ESF1 LF0 LF00 2x0l ortnoC retsigeR

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com POWER MANAGEMENT Register Map (Cont.) FL1,0: Control Override bits for S1/FL3, S2/FL2 and S3/FL1. Enable control is transferred to the FL pin (assuming the LEDs are first enabled) based on the following table: 1LF0 LFs utatSlortnoCniPLF 00 . delbasidnipLF-stibretsigerybdeniatniamlortnoC 01 . nipLFehtybdellortnocelbane1LF/3S 10 . nipLFehtybdellortnocselbane2LF/2S,1LF/3S 11 . nipLFehtybdellortnocselbane3LF/1S,2LF/2S,1LF/3S SC614 Slave Address Following a start condition, the master must output the address of the slave it is accessing. The most significant six bits of the slave address are the device type identifier (ID). For the SC614 this is fixed at 111000[ASEL]. The next significant bit addresses a particular device. A system can have up to two SC614 devices on the same bus. The two addresses are defined by the state of the ASEL input (see Table below). REIFITNEDIEPYTECIVEDS SERDDAECIVEDW /R 111000 0=DNGotLESAniP 1=NIVotLESAniP X

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com State Diagrams When the SC614 is first enabled, it starts up in Sleep Mode, with the registers at their reset values and the charge pump off. The bandgap reference will be operating, the input voltage will be monitored for UVLO and the serial interface will be monitored for any activity. This is the lowest power state for the device where it can be communicated with. In order to activate the charge pump it is necessary to clear the Sleep bit to 0 to enter Run Mode. When in Run Mode the charge pump is activated in 1x mode with VOUT = 1.5V, and all of the optional functions of the device may be accessed. Shutdown Sleep Mode ( SLEEP = 1 ) Power Off VIN high , EN low EN = High VIN , EN high Run Mode ( SLEEP = SLEEP = Lowest Power State. All internal functions powered down Bandgap up, UVLO and serial interface monitoring active only Bandgap up, UVLO and serial interface monitoring active, charge pump running with VOUT = 1.5V Start-Up

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com POWER MANAGEMENT State Diagrams (Cont.) Power Management Sleep Mode (Register contents stored) Shutdown (EN low) Sleep Mode (Register contents reset) SLEEP = 1 from any Run Mode SWRST = 1 from any Run Mode EN low from any mode SLEEP = 0 Return to previous Mode SLEEP = 0 Run Mode There are three options for powering down the SC614 (other than writing 0x00 to each Current Control Register or the LED On/Off Control Register): Sleep Mode (SLEEP = 1) Setting this bit to 1 at any time will power down the charge pump. The register contents will be stored, the bandgap reference will remain active, and UVLO and serial interface monitoring will continue. Clearing this bit will resume operation as before. Sleep Mode from Reset (SWRES = 1) Setting SWRES to 1 will reset all registers (clearing the SWRES bit), causing the part to enter Sleep Mode but with all registers at their reset values (0x00 for registers 0x00 through 0x07, 0x20 for Control Register 0x08 (SLEEP = 1). Upon clearing the SLEEP bit, the SC614 will enter run mode and will require writing to the registers to commence driving LEDs. Shutdown (EN low) All internal functions are powered down. Pulling EN high will enter Sleep Mode with all registers reset. Device Operation With All LEDs Disabled If the SC614 is driving LEDs and then all LEDs are disabled, the device reverts to 1x mode with a nominal output voltage of 3V. This decreases the response time when the LEDs are enabled once more. Quiescent current in this mode will be 700 μA (nom).

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com General Operation The SC614 contains a fractional charge pump, mode selection circuitry, serial I/O logic, serial data registers and current regulation circuitry for 7 LED outputs. All are depicted in the Block Diagram on page 5. The fractional charge pump multiplies the input voltage by 1, 1.5 or 2 times the input voltage. The charge pump switches at a fixed frequency that is bit selectable to 1.33MHz or 250kHz. The default frequency is 250kHz. The charge pump does not switch during 1x mode, saving power and improving efficiency. The mode selection circuitry automatically selects the mode as 1x, 1.5x or 2x based on circuit conditions such as LED voltage, input voltage and load current. 1x is the most efficient mode, followed by 1.5x and 2x modes. At lower input voltages a stronger mode may be needed to maintain regulation. If so, the mode will change first to 1.5x and then later to 2x. 2x mode usually operates for a much shorter run time compared to 1x mode, and 2x mode maintains the output until the battery is discharged to 3V or less. The LED requiring the highest voltage drop will determine the output voltage needed to drive all outputs with sufficient anode voltage. Comparing all cathodes and regulating VOUT for the LED with the lowest cathode voltage ensures sufficient bias for all LEDs. The LED outputs are controlled through the serial data registers, found in the Register Map on page 8. LED on/ off functions are independently controlled, so that any combination of LEDs may be switched on. Seven (7) current regulating circuits sink currents from the LEDs as set by the Current Control registers. For LCD backlighting applications current matching is crucial, and LEDs with matched forward voltage will produce the best possible matched currents. The SC614 is capable of dealing with V F mis-matches up to 0.5V. For best matching performance, however, it is recommended that the LED to LED difference, ΔV F, be under 250mV. Designing for Lowest Possible Battery Current The battery current and efficiency of the SC614 are mostly dependent on the charge pump mode of operation. To get the best performance from the SC614 it is better to use LEDs with consistantly lower V F. Lower VF will keep the charge pump in 1x mode longer and will use less battery current, extending the run time of the battery. Mode Transition Threshold Voltage and Hysteresis Mode transition threshold voltage refers to the input voltage at the point when the charge pump changes from a weaker mode (lower numerically) to a stronger mode (higher numerically). V TRANS1X is the transition from 1x to 1.5x mode, and VTRANS1.5X is the transition from 1.5x to 2x mode. Mode transition voltages V TRANS1X and V TRANS1.5X can be estimated by the following equations: VTRANS1X = V F + V ILED + I OUT 1.0 VTRANS1.5X = (V F + V ILED + I OUT 5.5) / 1.5 where VF is the highest forward voltage of the operating LEDs, VILED is the current sink voltage for that LED (typically VILED=150mV) and I OUT is the sum of all operating LED currents. The mode transition circuitry has hysteresis built in to prevent the device from toggling between modes when the input voltage is right at the threshold of mode change. There is 100mV of hysteresis between 1.5x and 1x modes and 200mV of hysteresis between 2x and 1.5x modes. Efficiency Power efficiency can be estimated for any particular battery voltage as follows: η = [V OUT IOUT / V IN (IOUT Mode+IQ)] 100 % where: V OUT = V F+ VILED (defined in the above section). and, I Q = 1mA in 1x mode, 1.4mA in 1.5x mode and 1.8mA in 2x mode (250kHz). LED Current Accuracy The LED current is set by the Current Control registers 0x01 through 0x07. The guaranteed accuracy of any current sink is +/-8% at a current setting of 20mA, with the typical accuracy much higher at +/-1.5%. For example, if the Current Control registers are configured such that each LED current will be 20mA (0x32 written to register 0x01 through 0x07), the actual LED currents Applications Information

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com POWER MANAGEMENT would be between 18.4mA and 21.6mA (+/-8%). All 7 outputs meet this requirement over the industrial temperature range. To calculate the accuracy based upon the actual measured LED current, I LED_ACC, use the following formula: ( ) %100I III )SET(LED )SET(LED)Measured(LED ACC_LED •−±= Current Matching The current matching percentage is a figure that represents how closely matched LEDs are that are set to the same current. For any particular LED within a group of LEDs set to the same current, the matching is the ΔI for that LED from the average of the minimum and maximum value of the group (i.e. the center of the measured current range) expressed as a percentage of that average. Current matching is calculated as follows: %100 II Ior%100 II II MINMAX MIN MINMAX MAX LED_LED • ⎛ +• ⎛ += Which can be reduced to: ( ) () %100II III MINMAX MINMAX LED_LED •+ −±= Protection Circuitry The SC614 also provides protection circuitry that prevents the device from operating in an unspecified state. These include Output Over-Voltage Protection (OVP), Over-Temperature Protection (OTP), Over-Current Protection (OCP) and Short-Circuit Protection (SCP). Output Over-Voltage Protection Output over-voltage protection is included to prevent the SC614 from generating an output voltage that could damage other devices connected to it such as load LEDs any bypass capacitors. When the output voltage exceeds 5.7V, the OVP circuitry disables the charge pump until the output voltage decreases to an acceptable level. Usually the only reason for the output voltage to trip OVP is if one of the LEDs goes open. If this happens the SC614 will raise the output voltage to attempt to bring Applications Information (Cont.) that LED current back into regulation. When the OVP trip point is reached, the charge pump will be turned off. Any current sinks that measure close to ground will be turned off in an attempt to isolate the faulty LED. Once the output voltage drops enough the charge pump will resume operation. Over-Temperature Protection The over-temperature protection circuitry helps to prevent the device from overheating and experiencing a catastrophic failure. When the junction temperature exceeds 160°C the output is disabled and the device enters sleep mode. All register settings are retained. The junction temperature must drop by more than the hysteresis of 10°C before the part exits sleep mode and re-commences normal operation. Over-Current and Short Circuit Protection Adaptive current limit circuitry is provided to protect the device from various levels of shorts from resistive to full shorts as well as to limit in-rush current at start-up and during mode transitions. The current limit levels adjust to the total output current set for the LEDs and thus will be higher when very high levels of currents are programmed, such as for flash operation. The current limit levels are set to ensure that the device will not current limit under normal operation. When an output short circuit occurs, the device folds back the current limit level to a nominal 300mA. If sustained current limit occurs the device may shut down due to internal heating triggering the OTP circuitry. Capacitor Selection The SC614 is designed to use low-ESR ceramic capacitors for all four external capacitors: input, output and charge pump bucket capacitors. Ideal performance is achieved when the bucket capacitors (C3 and C4 in the application circuit) are exactly equal. Note: It is recommended that X5R or X7R capacitors are used for best performance. Thermal Resistance and Heat Management The SC614 is packaged in a thermally efficient MLPQ24 package that has a thermal pad to remove the heat from the part. It is intended to be connected using multiple vias to the ground plane, and the thermal resistance rating of 40°C/W reflects this. A good layout will enable the part to operate at maximum output current ratings without tripping the OTP circuitry.

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com Applications Information (Cont.) Layout Guidelines The following layout is suggested (shown as three-layer (top, bottom and ground layer) only for clarity). C1 is the input capacitor which should be placed close to pin 17. C2 is the output capacitor which should be placed close to pin 16. The capacitors C3 and C4 are the bucket capacitors which can carry up to the full load current of 434mA pulsed for one half clock cycle (at either 250kHz or 1.33MHz depending upon selected operating frequency). Multiple vias should be used whenever it is necessary to change layers on nets connecting to CIN, VOUT, C1+, C1-, C2+ and C2-. As mentioned before, the thermal pad should connect to ground using multiple vias, with 4 vias recommended. Top Copper and Top SilkscreenLayout Guidelines Schematic 2u2 C3 1u C4 1u VIN11 VIN17 EN2 SDA7 SCL8 ASEL5 SDIM3 MD I M4 FL6 VOUT 9 VOUT 16 M1 1 M2 24 M3 23 M4 22 S1/FL3 20 S2/FL2 19 S3/FL1 18 GND12 GND21 TPAD25 C1+10 C1-13 C2+15 C2-14 SC614 VBAT

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com POWER MANAGEMENT Bottom Copper Ground Layer Applications Information (Cont.)

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com Application Examples Main Backlight Plus Flash LED 434mA Max (500ms) LED LED LED LED 32mA Max 32mA Max 32mA Max 32mA Max 306mA Max. 2u2 C3 1u C4 1u VIN11 VIN17 EN2 SDA7 SCL8 ASEL5 SDIM3 MD I M4 FL6 VOUT 9 VOUT 16 M1 1 M2 24 M3 23 M4 22 S1/FL3 20 S2/FL2 19 S3/FL1 18 GND12 GND21 TPAD C1+10 C1-13 C2+15 C2-14 SC614 EN SDA SCL SDIM FL MDIM 328mA Max Continuous VBAT Pull-up Pull-up VLOGIC Note: R1 and R2 pull-up resistors are a requirement of the I2C specification MAIN BACKLIGHT FLASH Features:

• Up to 4 LED main backlight with up to 32mA per LED
• PWM dimming of backlight using MDIM pin
• Up to 306mA flash capability controlled by FL pin Register Settings (20mA backlight currents and 300mA flash current used as an example): 0x00: set to 0x7F to enable all 7 current sinks for use 0x01 through 0x04: set to 0x32 for 20mA per current sink 0x05 through 0x07: set to 0xFA for 100mA per current sink, 300mA total 0x08: set to 0x46 for Flash Mode enabled, 250kHz charge pump frequency, FL pin controls S1/FL3, S2/FL2 and S3/FL1

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com POWER MANAGEMENT Application Examples (Cont.) Main Backlight Plus Sub-Backlight LED 434mA Max (500ms) LED LED LED LED 32mA Max 32mA Max 32mA Max 32mA Max 2u2 C3 1u C4 1u VIN11 VIN17 EN2 SDA7 SCL8 ASEL5 SDIM3 MDIM4 FL6 VOUT 9 VOUT 16 M1 1 M2 24 M3 23 M4 22 S1/FL3 20 S2/FL2 19 S3/FL1 18 GND12 GND21 TPAD C1+10 C1-13 C2+15 C2-14 SC614 EN SCL SDA FL SDIM MDIM VBAT Pull-up Pull-up VLOGIC Note: R1 and R2 pull-up resistors are a requirement of the I2C specification SUB BACKLIGHTMAIN BACKLIGHT 102mA Max 102mA Max 102mA Max LED LED 328mA Max Continuous Features:

• Up to 4 LED main backlight with up to 32mA per LED
• PWM dimming of main backlight using MDIM pin
• Up to 3 LED sub-backlight with up to 32mA per LED
• PWM dimming of sub-backlight using SDIM pin Register Settings (20mA backlight currents used as an example): 0x00: set to 0x7F to enable all 7 current sinks for use (or as needed if less) 0x01 through 0x07: set to 0x32 for 20mA per current sink 0x08: set to 0x00 for Flash Mode disabled (FL pin inactive) and 250kHz charge pump frequency

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com Application Examples (Cont.) Main Backlight Plus Sub-Backlight Plus Flash LED 434mA Max (500ms) LED LED LED LED 102mA Max 102mA Max 102mA Max 102mA Max 2u2 C3 1u C4 1u VIN11 VIN17 EN2 SDA7 SCL8 ASEL5 SDIM3 MDIM4 FL6 VOUT 9 VOUT 16 M1 1 M2 24 M3 23 M4 22 S1/FL3 20 S2/FL2 19 S3/FL1 18 GND12 GND21 TPAD C1+10 C1-13 C2+15 C2-14 SC614SDA EN SDIM SCL FL MDIM VBAT Pull-up VLOGIC Pull-up Note: R1 and R2 pull-up resistors are a requirement of the I2C specif ication MAIN BACKLIGHT SUB BACKLIGHT 102mA Max 102mA Max 102mA Max LED LED Balance Balance FLASH 328mA Max Continuous Features:

• Up to 4 LED main backlight with up to 32mA per LED
• PWM dimming of main backlight using MDIM pin
• Up to 2 LED sub-backlight with up to 32mA per LED using resistor current balancing
• PWM dimming of sub-backlight using SDIM pin
• Up to 204mA flash capability controlled by FL pin Register Settings (20mA backlight currents and 200mA flash current used as an example): 0x00: set to 0x7F to enable all 7 current sinks for use 0x01 through 0x04: set to 0x32 for 20mA per current sink 0x05: set to 0x64 for 40mA for this current sink (20mA per LED) 0x06 and 0x07: set to 0xFA for 100mA per current sink, 200mA total 0x08: set to 0x44 for Flash Mode enabled, 250kHz charge pump frequency, FL pin controls S2/FL2 and S3/FL1

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com POWER MANAGEMENT Application Examples (Cont.) Main Backlight Plus RGB Indicator LED LED LED LED 2u2 C3 1u C4 1u VIN11 VIN17 EN2 SDA7 SCL8 ASEL5 SDIM3 MDIM4 FL6 VOUT 9 VOUT 16 M1 1 M2 24 M3 23 M4 22 S1/FL3 20 S2/FL2 19 S3/FL1 18 GND12 GND21 TPAD C1+10 C1-13 C2+15 C2-14 SC614 SDA EN SDIM SCL FL MDIM VBAT Pull-up VLOGIC Pull-up Note: R1 and R2 pull-up resistors are a requirement of the I2C specification MAIN BACKLIGHT RGB INDICATOR RGB_LED 102mA Max 102mA Max 102mA Max 102mA Max 328mA Max Continuous 102mA Max 102mA Max 102mA Max 434mA Max (500ms) Features:

• Up to 4 LED main backlight with up to 32mA per LED
• PWM dimming of backlight using MDIM pin
• 3 current sinks for RGB with up to 32mA per LED
• Dimming and color rotation of RGB over I 2C interface Register Settings (20mA backlight currents and as required on the fly RGB current used as an example): 0x00: set to 0x7F to enable all 7 current sinks for use 0x01 through 0x04: set to 0x32 for 20mA per current sink 0x05 through 0x07: set to as required on the fly for each color 0x08: set to 0x00 for Flash Mode disabled (FL pin inactive) and 250kHz charge pump frequency

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com Using the I2C Serial Port The I2C General Specification The SC614 is a read-write slave-mode I 2C device and complies with the Philips I 2C standard Version 2.1 dated January 2000. The SC614 has nine user-accessible internal 8-bit registers. The I 2C interface has been designed for program flexibility, in that once the slave address has been sent to the SC614 enabling it to be a slave transmitter/receiver any register can be written or, read from independently of each other. While there is no auto increment/decrement capability in the SC614 I 2C logic, a tight software loop can be designed to randomly access the next register independent of which register you begin accessing. The start and stop commands frame the data- packet and the repeat start condition is allowed if necessary. SC614 Limitations to the I 2C specifications Seven bit addressing is used and ten bit addressing is not allowed. Any general call address will be ignored by the SC614. The SC614 is not CBUS compatible. Finally, the SC614 can operate in standard mode (100kbit/s) or fast mode (400kbit/s). Supported Formats Direct Format - Write: The simplest format for an I 2C write is the direct format write. After the master sends a start condition, the slave address is sent followed by an eighth bit indicating a write. The SC614 then acknowledges that it is being addressed, and the master responds with an 8-bit data byte consisting of the target register address. The slave acknowledges and the master sends the appropriate 8-bit data byte. Once again the slave acknowledges and the master terminates the transfer with a stop condition. S sserddAevalS WA sserddAretsigeRA ataDA P S: Start Condition Slave Address: 7 bit W: Write = 0 Register Address: 8 bit A: Acknowledge (SDA low) Data: 8 bit P: Stop Condition Shaded represents transmission from master to slave and unshaded represents transmission from slave to master. Combined Format (Read/Write): After a start condition, the slave address is sent followed by an eighth bit indicating a write. The SC614 then acknowledges that it is being addressed, and the master responds with an 8 bit data byte consisting of the target register address. The slave acknowledges once more and the master sends the repeated start condition. Once again, the slave address is sent, followed by an eighth bit indicating a read or write. The slave responds with an acknowledge. If the command was a write, the master sends the appropriate 8-bit data byte. Once again the slave acknowledges and the master terminates the transfer with a stop condition. If the command was a read, the slave sends the appropriate 8-bit data byte, to which the master sends a not acknowledge and then terminates the transfer with a stop condition. S sserddAevalS WA sserddAretsigeRA rS sserddAevalS W/RA a taD )1( N/A )1( P S: Start Condition N: Not Acknowledge(SDA high) (1) W: Write = 0 P: S top Condition A: Acknowledge (SDA low) Slave Address: 7 bit Sr: Repeated Start Condition Register Address: 8 bit R: Read = 1 Data: 8 bit Shaded represents transmission from master to slave and unshaded represents transmission from slave to master. (1) Not shaded because transfer direction depends upon R/W bit.

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com POWER MANAGEMENT Stop Separated Reads: A further form of read is available which is, in effect, an extension of the combined format read. This format allows a master to set up the register address pointer for a read, and return to that slave some time later to read the data. After a start condition, the slave address is sent, followed by a write. The SC614 then acknowledges that it is being addressed, and the master responds with the 8-bit target register address. The master then sends a stop or repeated start condition, and may address another slave. Some time later the master sends a start or repeated start condition, and a valid slave address is sent, followed by a read. The SC614 then acknowledges and returns the data at the register address location that had previously been set up. S sserddAevalS WA sserddAretsigeRA P retsaM( sesserddA rehtO )sevalS rS/S sserddAevalS RA a taD N P S: Start Condition Slave Address: 7 bit W: Write = 0 Register Address: 8 bit A: Acknowledge (SDA low) Data: 8 bit P: Stop Condition Sr: Repeated Start R: Read = 0 Shaded represents transmission from master to slave and unshaded represents transmission from slave to master. Using the I 2C Serial Port (Cont.)

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com Typical Characteristics 100 VBA T(V) IBA T(mA) LED 5-7 = 20mA LED VF = 3.276V Battery Current (Sub-only) 100 150 200 250 LED 1-7 = 20mA LED VF = 3.340V VBA T(V) IBA T(mA) Battery Current (Main and Sub) 100 Conversion Efficiency Utilized Power Efficiency % Efficiency VBA T(V) LED 5-7 = 20mA LED VF = 3.276V Power Effi ciency (Sub-only) 100 Conversion Efficiency Utilized Power Efficiency VBA T(V) LED 1-7 = 20mA LED VF = 3.340V % Efficiency Power Effi ciency (Main and Sub) -3 .5 -2 .5 -1 .5 -0 .5 0.5 1.5 2.5 3.5 LED Matc hing (%) VBA T(V) LED 1-7 = 20mA Typical LED Matching (Main and Sub) -6 .0 -4 .0 -2 .0 0.0 2.0 4.0 6.0 Max Min Min LED Accuracy % VBA T(V) Typical LED Accuracy (Main and Sub)

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com POWER MANAGEMENT Typical Characteristics (Cont.) 300 400 500 600 700 800 900 VBA T(V) IBA T(mA) LED 1-4 = 20mA LED 5-7 = 100mA LED VF = 3.388V Battery Current (Main and Flash) 100 120 140 IBA T(mA) VBA T(V) LED 1-4 = 20mA LED VF = 3.23V Battery Current (Main only) 100 Utilized Power Efficiency Conversion Efficiency LED 1-4 = 20mA LED 5-7 = 100mA LED VF = 3.388V % Efficiency VBA T(V) Power Effi ciency (Main and Flash) 100 Utilized Power Efficiency Conversion Efficiency LED 1-4 = 20mA LED VF = 3.23V % E fficiency VBA T(V) Power Effi ciency (Main only)

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com e bxN D/2 N PIN 1 INDICATOR 4.153.85 4.00 4.153.85.157 .151 .163 .151 .163 aaa C A C (LASER MARK) D E B A SEATING PLANE LxN E/2 bbb C A B INCHES .020 BSC b .007 bbb aaa N E L e D .011 .100 DIM A MIN .000 .031 0.50 2.80 0.30 2.55 .004 .004 .016 .157 .106 .020 .110 0.10 0.10 0.40 4.00 2.70

0.50 BSC

0.05 1.00 DIMENSIONS MIN 0.00 NOM (.008) .035 .001 MAX .002 .040 NOM 0.80 0.02 (0.20) 0.90 CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. NOTES: Outline Drawing MLPQ-24 4 x 4

© 2006 Semtech Corp. POWER MANAGEMENT SC614 United States Patent No. 6,504,422 www.semtech.com POWER MANAGEMENT THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR NOTES: DIM X Y H K P C G MILLIMETERSINCHES (3.95) .010 .033 .122 .021 .106 .106 (.155) 0.25 0.85 2.70 0.50 2.70 3.10 DIMENSIONS COMPANY'S MANUFACTURING GUIDELINES ARE MET. 4.80.189Z K G ZH(C) X P Land Pattern MLPQ-24 4 x 4 Contact Information Semtech Corporation Power Management Products Division

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