SLLS390 – SEPTEMBER 1999TLC5921LED DRIVER DDrive Capability and Output CountsDDDDDDDDDDDDD – 80 mA (Current Sink) x 16 BitsConstant Current Output Range– 1 to 80 mA (Current Value Setting for AllOutput Terminals Using External Resistor)Constant Current Accuracy– ±1% (Typ)– ±4% (Max) (Maximum Error BetweenBits, All Bits On)Voltage Applied to Constant Current OutputTerminal– Minimum 0.6 V (Output Current 40 mA)– Minimum 1 V (Output Current 80 mA)Data Input– Clock Synchronized 1 Bit Serial InputData Output– Clock Synchronized 1 bit Serial Output(With Timing Selection)Input/Output Signal Level...CMOS LevelPower Supply Voltage...4.5 V to 5.5VMaximum Output Voltage...17 V (Max)Data Transfer Rate...20 MHz (Max)Operating Free-Air Temperature Range–20°C to 85°CAvailable in 32 Pin HTSSOP DAP Package(PD=3.9 W,TA = 25°C)LOD Function...LED Open Detection(Error Signal Output at LED Disconnection)TSD Function...Thermal Shutdown (TurnOutput Off When Junction TemperatureExceeds Limit)DAP PACKAGE(TOP VIEW)GNDBLANKXLATSCLKSINPGNDOUT0OUT1PGNDOUT2OUT3OUT4OUT5PGNDOUT6OUT71234 5671011121314151632313029282726252423222120191817VCCIREFSOMODEXDOWNSOUTPGNDOUT15OUT14PGNDOUT13OUT12OUT11OUT10PGNDOUT9OUT8descriptionThe TLC5921 is a current-sink constant current driver incorporating shift register and data latch. The currentvalue at constant current output can be set by one external register. The device also incorporates thermalshutdown (TSD) circuitry which turns constant current output off when the junction temperature exceeds thelimit, and LED open detection (LOD) circuitry to report the LED was disconnected.Please be aware that an important notice concerning availability, standard warranty, and use in critical applications ofTexasInstruments semiconductor products and disclaimers thereto appears at the end of this data sheet.PRODUCTION DATA information is current as of publication date.Products conform to specifications per the terms of Texas Instrumentsstandard warranty. Production processing does not necessarily includetesting of all parameters.Copyright © 1999, Texas Instruments IncorporatedPOST OFFICE BOX 655303 DALLAS, TEXAS 75265•1SLLS390 – SEPTEMBER 1999TLC5921LED DRIVER functional block diagramVCCSOMODESCLKSIN16 bitsShift RegisterTiming SelectorSOUTXLAT100 kΩ100 kΩBLANKIREFGNDPGNDOUT016 bitsData Latch16 bits Constant Current DriverandLED Disconnection detectionXDOWNTSDOUT152POST OFFICE BOX 655303 DALLAS, TEXAS 75265• SLLS390 – SEPTEMBER 1999TLC5921LED DRIVER equivalent input and output schematic diagramsInput (except SCLK)VCCInput (SCLK)VCCINPUTINPUTGNDGNDSOUTVCCOUTPUTGNDXDOWNXDOWNGNDOUTnOUTnGNDPOST OFFICE BOX 655303 DALLAS, TEXAS 75265•3SLLS390 – SEPTEMBER 1999TLC5921LED DRIVER Terminal FunctionsTERMINALNAMESINSOUTSCLKNO.5284I/OIOI1 bit serial data input1 bit serial data outputClock input for data transfer. All the data in the shift register is shifted to MSB by 1 bitsynchronizing to the rising edge of SCLK, and data at SIN is shifted to LSB at the same time.(Schmitt buffer input)DESCRIPTIONXLAT3ILatch. When XLAT is high, data on shift register goes through latch. When XLAT is low, datais latched. Accordingly, if data on shift register is changed during XLAT high, this new valueis latched (level latch). This terminal is internally pulled down with 100kΩ.Timing select for serial data output. When SOMODE is low, output data on SOUT is changedsynchronizing to the rising edge of SCLK. When SOMODE is high, output data on SOUTis changed synchronizing to the falling edge of SCLK.Constant current output.SOMODE30IOUT0 – OUT157,8,10,11,12,13,15,16,17,18,20,21,22,23,25,262OBLANKIBlank(Light off). When BLANK is high, all the output of constant current driver is turned off.When BLANK is low and data written to latch is 1, the corresponding constant current outputturns on (LED on). This terminal is internally pulled up with 100kΩ.IREF3129321IConstant current value setting. LED current is set to desired value by connecting externalresistor between IREF and GND. The 38 times current compared to current across externalresistor sink on output terminal.Error output. XDOWN is configured as open collector. It goes low when TSD or LODfunctions.Power supply voltageGroundXDOWNVCCOGNDPGNDTHERMAL PAD6,9,14,19,24,27package bottomGround for LED driver. (Internally connected to GND)Heat sink pad. This pad is connected to the lowest potential to IC or thermal layer.absolute maximum ratings (see Note 1)†Supply voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.3 V to 7 VOutput current (dc), IO(LC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 mAInput voltage range, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.3 V to VCC + 0.3 VOutput voltage range, VO(SOUT), VO(XDOWN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.3 V to VCC + 0.3 VOutput voltage range, VO(OUTn) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.3 V to 18 VStorage temperature range, Tstg –40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . °C to 150°CContinuous total power dissipation at (or below) TA = 25°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.9 WPower dissipation rating at (or above) TA = 25°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.4 mW/°C†Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, andfunctional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is notimplied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.NOTE 1:All voltage values are with respect to GND terminal.4POST OFFICE BOX 655303 DALLAS, TEXAS 75265• SLLS390 – SEPTEMBER 1999TLC5921LED DRIVER recommended operating conditionsdc characteristicsPARAMETERSupply voltage, VCCVoltage applied to constant current output, VOHigh-level input voltage, VIHLow-level input voltage, VILCONDITIONSOUT0 to OUT15 off0.8VCCGNDMIN4.5NOM5MAX5.517VCC0.2VCCUNITVVVVHigh-level output current, IOHLow-level output current, IOLVCC = 4.5 V, SOUTVCC = 4.5 V, SOUT, XDOWNOUT0 to OUT15–11mAmA°CConstant output current, IO(LC)Operating free-air temperature range, TA80–2085ac characteristics, MIN/MAX: VCC = 4.5 V to 5.5 V, TA = –20 to 85°CTYP: VCC = 5 V, TA = 25°C (unless otherwise noted)PARAMETERfSCLKSCLKclockfrequencySCLK clock frequencySCLK pulse durationXLAT pulse durationRise/fall timeSetuptimeSetup timeHoldtimeHold timeCONDITIONSAt single operationAt cascade operation (SOMODE = L)MINTYPMAX2015UNITMHznsnsnsnsnstwh/twltwhtr/tftsuth2010552020100SIN–SCLKXLAT–SCLKSIN–SCLKXLAT–SCLKPOST OFFICE BOX 655303 DALLAS, TEXAS 75265•5SLLS390 – SEPTEMBER 1999TLC5921LED DRIVER electrical characteristics, MIN/MAX: VCC = 4.5 V to 5.5 V, TA = – 20 to 85°CTYP: VCC = 5 V, TA = 25°C (unless otherwise noted)PARAMETERTEST CONDITIONSMINTYPMAXUNITVVOHVOLIIHigh-level output voltageLow-level output voltageInput currentIOH = – 1 mAIOL = 1 mAVI = VCC or GND (except BLANK, XLAT)VCC–0.5V0.5±137114.5915205045901VµAInput signal is static,VO = 1 V,R(IREF) = 10 kΩ,All output bits turn offInput signal is static,VO = 1 V RIREF = 1300 Ω,All output bits turn offInput signal is static,VO = 1 V, R(IREF) = 0 Ω,All output bits turn offData transfer,R(IREF) = 1300 Ω,Data transfer,R(IREF) = 0 Ω,VO = 1 V,VO = 1 VICCSupply currentmAVO = 1 V,All output bits turn on153080VO = 1 V,All output bits turn onIOL(C1)IOL(C2)IlkglkConstant output currentConstant output currentR(IREF) = 1300 Ω3570mAmAµAµA%R(IREF) = 0 ΩConstantoutputleakagecurrentConstant output leakage currentConstant output current error between bitChanges in constant output currentdepend on supply voltageChanges in constant output currentdepend on output voltageTSD detection temperatureReference voltageLED disconnection detection voltageOUT0 to OUT15 (V(OUTn) = 15 V)XDOWN (5V pullup)0.1∆IO(LC)VO = 1 V,R(IREF) = 0 Ω,All output bits turn onVref = 1.3 V±1±1±2±4±4±6I∆O(LC1)I∆O(LC2)T(tsd)Vref%/V%/V°CVVVO = 1 Vto3 V,Vref = 1.3 V,R(IREF) = 0 ΩR(IREF) = 1300 Ω,1 bit output turn onJunction temperature1501601.30.3170V(LEDDET)switching characteristics, CL = 15 pFPARAMETERTEST CONDITIONSMINTYPMAXUNITnsnstrtfRisetimeRise timeFalltimeFall timeSOUTSOUTOUTn15520OUTn (see Figure 1)30030040030060050020156504001000100035BLANK↑–OUTnBLANK↓–OUTntpdPropagation delay timeBLANK↑–XDOWN (see Note 2)BLANK↓–XDOWN (see Note 2)SCLK–SOUTns10NOTE 2:At external resistor 5 kΩ6POST OFFICE BOX 655303 DALLAS, TEXAS 75265• SLLS390 – SEPTEMBER 1999TLC5921LED DRIVER PARAMETER MEASUREMENT INFORMATIONVCC51 ΩVCCIREF1300 ΩGNDOUTn15 pFFigure 1. Rise Time and Fall Time Test Circuit for OUTn100%90%10%0%VIH or VOH100%50%VIL or VOLtrtftd10%VIL or VOLVIH or VOH100%50%0%twhtwlVIH100%50%VIH or VOHVIL0%VIL or VOLFigure 2. Timing RequirementsPOST OFFICE BOX 655303 DALLAS, TEXAS 75265•7SLLS390 – SEPTEMBER 1999TLC5921LED DRIVER PRINCIPLES OF OPERATIONsetting for constant output current valueThe constant current value is determined by external resistor, R(IREF) between IREF and GND. Refer constantoutput current characteristics shown on Figure 5 for this external resistor value.Note that more current flows if connect IREF to GND directly.constant output current operationWhen BLANK is low, the corresponding output is turned on if data latch value is 1, and turned off if data latchvalue is 0. When BLANK is high, all outputs are forced to turn off. If there is constant current output terminalleft unconnected (includes LED disconnection), it should be lighted on after writing zero to corresponding datalatch to its output. If this operation is not done, supply current through constant current driver will increase.shift register latchThe shift register latch is configured with 16 × 1 bits. The 1 bit for constant current output data represents ONfor constant current output if data is 1, or OFF if data is 0. The configuration of shift register latch is shown inbelow.Data LatchOUT15Data(1 bits)OUT14Data(1 bits)OUT1Data(1 bits)OUT0Data(1 bits)XLATCHShift RegisterSCLKSINSOUT161521Figure 3. Relationship Between Shift Register and LatchSOUT output timing selectionBy setting level of SOMODE, the SOUT output timing can be changed. When SOMODE is set to low, data isclocked out to SOUT synchronized on the rising edge of SCLK, and when SOMODE is set to high, data isclocked out to SOUT synchronized on the falling edge of SCLK. When SOMODE is set to high and shiftoperation is done, the data shift error can be prevented even though SCLK signal is externally buffered in serial.Note that the maximum data transfer rate in cascade operation is slower than that when SMODE is set to low.TSD (thermal shutdown)When the junction temperature exceeds the limit, TSD starts to function and turn constant current output off andXDOWN goes low. Since XDOWN is configured with open-collector output, the outputs of multiple ICs can beconcatenated. To recover from constant current output off-state to normal operation, power supply should beturned off and then turned on after several seconds.8POST OFFICE BOX 655303 DALLAS, TEXAS 75265• SLLS390 – SEPTEMBER 1999TLC5921LED DRIVER PRINCIPLES OF OPERATIONLOD function (LED open detection)If any terminal voltage of constant current output (OUT0 TO 15) to be turned on is approximately below 0.3 V,XDOWN output goes low during output on by knowing LED disconnection. This function is operational forsixteen OUTn individually. To know which constant current output is disconnected, the level of XDOWN isrepeatedly checked 16 times from OUT0 to OUT15 turning one constant current output on. The power supplyvoltage for LED should be set to that the constant current output is applied to above 0.4 V to prevent fromXDOWN low when LED is lighting on normally. Note that on-time should be minimum1µs after the constantcurrent output is turned on since XDOWN output is required approximately 1 µs.As discussed earlier, XDOWN is used for both TSD and LOD function. Therefore, BLANK is used to know whichone of TSD or LOD worked when XDOWN went low at LED disconnection, that is, in this condition, when setBLANK to high, all the constant current outputs are turned off and LOD disconnection detection is disabled, then,if XDOWN was changed to high, LED disconnection must be occurred.Table 1 is an example for XDOWN output status using four LEDs.Table 1. XDOWN Output ExampleLED NUMBERLED STATUSOUTn1GOODONGOOD12NGONNG23GOODONGOOD34NGONNG4DETECTION RESULTXDOWNLED NUMBERLED STATUSOUTnDETECTION RESULTXDOWNLED NUMBERLED STATUSOUTnLOW (by case 2, 4)GOODONGOOD1NGONNG2GOODOFFGOOD3NGOFFGOOD4LOW (by case 2)GOODOFFGOODNGGOODOFFGOODNGOFFOFFDETECTION RESULTXDOWN2GOODGOODHIGH–IMPEDANCEnoise reduction : output slopeWhen output current is 80 mA, the time to change constant current output to turn-on and turn-off is approximately150 ns and 250 ns respectively. This allows to reduce concurrent switching noise occurred when multipleoutputs turn or off at the same time.thermal padThe thermal pad should be connected to GND to eliminate the noise influence since it is connected to the bottomside of IC chip. Also, desired thermal effect will be obtained by connecting this pad to the PCB pattern with betterthermal conductivity.POST OFFICE BOX 655303 DALLAS, TEXAS 75265•9SLLS390 – SEPTEMBER 1999TLC5921LED DRIVER PRINCIPLES OF OPERATIONpower rating – free-air temperature3.93.22.01.480–2002585TA – Free–Air Temperature – °C0NOTES:A.The data is based on simulation result. When TI recommended print circuit board is used, derate linearly at the rate of 31.4mW/°Cfor operation above 25°C free-air temperature. VCC=5 V, IO(LC) = 80 mA, ICC is typical value.B.The thermal impedance will be varied depend on mounting conditions. Since PZP package established low thermal impedance byradiating heat from thermal pad, the thermal pad should be soldered to pattern with low thermal impedance.C.The material for PCB should be selected considering the thermal characteristics since the temperature will rise around the thermalpad.Figure 4. Power Rating10POST OFFICE BOX 655303 DALLAS, TEXAS 75265•Output Voltage (Constant Current) – VPD– Total Power Dissipation – W SLLS390 – SEPTEMBER 1999TLC5921LED DRIVER PRINCIPLES OF OPERATIONconstant output current10000066000R(ref)– Reference Resistance –(Ω)1320010000600027501800130010001040860730010001020304050607080Ilkg – Input Leakage Current – (mA)Conditions : VO = 1 V, Vref = 1.3 VNOTE:The resistor, R(IREF), should be located as close to IREF terminal as possible to avoid the noise influence.Figure 5. Current on Constant Current Output vs External ResistorPOST OFFICE BOX 655303 DALLAS, TEXAS 75265•11SLLS390 – SEPTEMBER 1999TLC5921LED DRIVER12SINSD15_ASD00_BSD01_BSD02_BSD14_BSD15_BSD00_CSD14_CSD15_CSD00_D1/fSCLKtsu (SIN–SCLK)SCLKth (XLAT–SCLK)XLATtsu (XLAT–SCLK)twl (SCLK)twh (SCLK)th (SIN–SCLK)Template Release Date: 7–11–94•POST OFFICE BOX 655303 DALLAS, TEXAS 75265BLANKSOMODEtd (SCLK–SOUT)td (SCLK–SOUT)td (SCLK–SOUT)SOUTSD00_ASD01_ASD02_ASD14_ASD15_ASD00_BSD01_BSD14_BSD15_BSD00_Ctd (BLANK–OUTn)td (BLANK–OUTn)OUTnDRIVER OFFDRIVER ONDRIVER OFFtd (BLANK–XDOWN)td (BLANK–XDOWN)XDOWNHI–Z(Note)NOTE :LED disconnectedFigure 6. Timing Diagram SLLS390 – SEPTEMBER 1999TLC5921LED DRIVER MECHANICAL DATADAP (R-PDSO-G**) 38 PINS SHOWNPowerPAD™ PLASTIC SMALL-OUTLINE PACKAGE0,65380,300,19200,13MThermal Pad(see Note D)6,20NOM8,407,800,15 NOMGage Plane1A190°–8°0,750,500,25Seating Plane1,20 MAX0,150,050,10PINS **DIMA MAX2,803011,103211,103812,60A MIN9,6010,9010,9012,404073257/A 07/97NOTES:A.B.C.D.All linear dimensions are in millimeters.This drawing is subject to change without notice.Body dimensions do not include mold flash or protrusion.The package thermal performance may be enhanced by bonding the thermal pad to an external thermal plane.This pad is electrically and thermally connected to the backside of the die and possibly selected leads.E.Falls within JEDEC MO-153PowerPAD is a trademark of Texas Instruments Incorporated.POST OFFICE BOX 655303 DALLAS, TEXAS 75265•13IMPORTANT NOTICE
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