LTC3789 – High Efficiency, Synchronous, 4-Switch …

1 LTC378913789fcFor more information applicaTionFeaTuresapplicaTionsDescripTi onHigh efficiency , Synchronous, 4-Switch buck - boost ControllerThe LT C 3789 is a high performance buck - boost switch-ing regulator controller that operates from input volt-ages above, below or equal to the output voltage. The constant-frequency, current mode architecture allows a phase-lockable frequency of up to 600kHz, while an output current feedback loop provides support for battery charging. With a wide 4V to 38V (40V maximum) input and output range and seamless, low noise transitions between operating regions, the LTC3789 is ideal for automotive, telecom and battery-powered operating mode of the controller is determined through the MODE/PLLIN pin.

2 The MODE/PLLIN pin can select between pulse-skipping mode and forced continuous mode operation and allows the IC to be synchronized to an external clock. Pulse-skipping mode offers high efficiency and low ripple at light loads, while forced continuous mode operates at a constant frequency for noise-sensitive PGOOD pin indicates when the output is within 10% of its designed set point. The LTC3789 is available in low pro-file 28-pin 4mm 5mm QFN and narrow SSOP and Power Lossn Single Inductor Architecture Allows VIN Above, Below or Equal to the Regulated VOUTn Programmable Input or Output Currentn Wide VIN Range: 4V to 38Vn 1% Output Voltage Accuracy: < VOUT < 38V n Synchronous Rectification: Up to 98% Efficiencyn Current Mode Controln Phase-Lockable Fixed Frequency.

3 200kHz to 600kHzn No Reverse Current During Start-Up n Power Good Output Voltage Monitorn Internal LDOn Quad N-Channel MOSFET Synchronous Driven VOUT Disconnected from VIN During Shutdownn True Soft-Start and VOUT Short Protection, Even in boost Moden Available in 28-Lead QFN (4mm 5mm) and 28-Lead SSOP Packagesn Automotive Systemsn Distributed DC Power Systemsn high Power Battery-Operated Devicesn Industrial Control+ F121kBOOST1TG1SW1BG1TG2 BOOST2SW2BG2 FABDC2200pF1000pF1 FCER10 F330 F16 H8kLTC3789 INTVCCEXTVCCSENSE+IOSENSE IOSENSE+FREQSGNDSENSE TA01105k, 1%VIN4V TO38 VVOUT12V5A+ 100 100 22 F50 VCERL, LT, LT C, LT M, Linear Technology, the Linear logo, Module and Burst Mode are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation.

4 All other trademarks are the property of their respective owners. Protected by Patents, including 5408150, 5481178, 5929620, 6580258, 7365525, (V)0 efficiency (%)POWER LOSS (W)9095858010152552030354075701004281060 123789 TA01bVOUT = 12 VILOAD = 5 ALTC378923789fcFor more information MaxiMuM raTingsInput Supply Voltage (VIN) ..40V to Driver Voltages (BOOST1, BOOST2).. 46V to Voltage (SW1, SW2) ..40V to 5 VCurrent Sense Voltages (IOSENSE+, IOSENSE ).. 40V to , BOOST2 SW1, SW2 ..6V to , TG2 SW1, SW2 ..6V to Voltage ..14V to Voltage ..6V to +, SENSE Voltages ..INTVCC to , SS Voltages ..INTVCC to (Note 1)VINSNS, VOUTSNS ..40V to , TG2, BG1, BG2 Voltages ..(Note 6)ITH, FREQ, ILIM Voltages ..INTVCC to Voltage.

5 To , PGOOD Voltage ..6V to Junction Temper atur e Range (Notes 2, 3) .. 40 C to 125 CStorage Temper atur e Range .. 65 C to 125 CINTVCC Peak Output Current ..100mALead Temper atur e (Soldering, 10 sec.) GN Package ..300 CorDer inForMaTionLEAD FREE FINISHTAPE AND REELPART MARKING*PACKAGE DESCRIPTIONTEMPERATURE RANGELTC3789 EGN#PBFLTC3789 EGN#TRPBFLTC378928-Lead Narrow Plastic SSOP 40 C to 125 CLTC3789 IGN#PBFLTC3789 IGN#TRPBFLTC378928-Lead Narrow Plastic SSOP 40 C to 125 CLTC3789 EUFD#PBFLTC3789 EUFD#TRPBF378928-Lead (4mm 5mm) Plastic QFN 40 C to 125 CLTC3789 IUFD#PBFLTC3789 IUFD#TRPBF378928-Lead (4mm 5mm) Plastic QFN 40 C to 125 CConsult LT C Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping more information on lead free part marking, go to: For more information on tape and reel specifications, go to.

6 VIEWGN PACKAGE28-LEAD NARROW PLASTIC SSOP2827262524232221201918171615 VFBSSSENSE+SENSE ITHSGNDMODE/PLLINFREQRUNVINSNSVOUTSNSILI MIOSENSE+IOSENSE PGOODSW1TG1 BOOST1 PGNDBG1 VININTVCCEXTVCCBG2 BOOST2TG2SW2 TRIM TJMAX = 125 C, JA = 80 C/W910 TOP VIEWUFD PACKAGE28-LEAD (4mm 5mm) PLASTIC QFN11121328 27 26 25 241423654321 SENSE ITHSGNDMODE/PLLINFREQRUNVINSNSVOUTSNSBOO ST1 PGNDBG1 VININTVCCEXTVCCBG2 BOOST2 SENSE+SSVFBPGOODSW1TG1 ILIMIOSENSE+IOSENSE TRIMSW2TG271718192021221681529 SGND TJMAX = 125 C, JA = 34 C/WEXPOSED PAD (PIN 29) IS SGND, MUST BE SOLDERED TO PCBpin conFiguraTionLTC378933789fcFor more information characTerisTicsSYMBOLPARAMETERCONDITIONS MINTYPMAXUNITSVINI nput Supply Voltage438 VVOUTO utput Feedback VoltageITH Voltage = (Note 4), TA = 40 C to 85 C ITH = , TA = 125 C, TA = 40 C to 125 Cl VIFBF eedback Current(Note 4) 15 50nAVREFLNREGR eference Voltage Line RegulationVIN = 4V to 38V (Note 4) VVLOADREGO utput Voltage Load Regulation(Note 4) Measured in Servo Loop, ITH Voltage = to 2V Measured in Servo Loop, ITH Voltage = 2V to l l % %gmTransconductance Amplifier gmITH = , Sink/Source 5 A (Note 4) DC Supply Current Normal Mode Shutdown (Note 5)

7 VRUN = 0V 3 40 60 mA AUVLOU ndervoltage LockoutINTVCC Ramping HystUndervoltage + ISENSE SENSE Pins CurrentVSENSE = VSENSE+ = 1 AIIOSENSE+ IIOSENSE IOSENSE Pins CurrentVIOSENSE = VIOSENSE+ = 10V1014 AISSSoft-Start Charge CurrentVSS = 0V234 AVRUN(ON)RUN Pin On-ThresholdVRUN (HYS)RUN Pin On-Hysteresis150mVIRUNRUN Pin Source AIRUN(HYS)RUN Pin Hysteresis Current5 AVSENSE(MAX)Maximum Current Sense Threshold buck Region, (IL Valley) boost Region, (IL Peak) VFB = VFB = l l 73 123 90 140 107 157 mV mVVSENSE(IAVG)Maximum Input/Output Average Current Sense ThresholdILIM = 0V ILIM Floating ILIM = INTVCC48 90 13050 100 106 160mV mV mVRDSPFET(ON)Driver Pull-Up RDSNFET(ON)Driver Pull-Down TG tr TG tfTop Gate Rise Time Top Gate Fall Time25 25ns nsBG tr BG tfBottom Gate Rise Time Bottom Gate Fall Time25 25ns nsTG/BG t1 DTop Gate Off to Bottom Gate On Delay Synchronous Switch-On Delay TimeCLOAD = 3300pF Each Driver (Note 6)60nsBG/TG t1 DBottom Gate Off to Top Gate On Delay Top Switch-On Delay TimeCLOAD = 3300pF Each Driver (Note 6)60nsDFMAX,BOOSTM aximum Duty Factor% Switch C On90%DON(MIN, boost )Minimum Duty Factor for Main Switch in boost Operation% Switch C On9%DON(MIN, buck )Minimum Duty Factor for Synchronous Switch in buck Operation% Switch B On9% The l denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25 C (Note 2).

8 VIN = 15V, VRUN = 5V, unless otherwise more information characTerisTics The l denotes the specifications which apply over the specified operating junction temperature range, otherwise specifications are at TA = 25 C (Note 2). VIN = 15V, VRUN = 5V, unless otherwise Linear RegulatorVINTVCCVINI nternal VCC < VIN < 40V, VEXTVCC = Load RegulationICC = 0mA to 20mA, VEXTVCC = VCC < VEXTVCC < Load RegulationICC = 0mA to 20mA, VEXTVCC = Switchover VoltageICC = 0mA to 20mA, EXTVCC Ramping and Phase-Locked LoopfNOMN ominal FrequencyVFREQ = Fixed FrequencyVFREQ = 0V175200225kHzfHIGHHigh Fixed FrequencyVFREQ = FrequencyMODE/PLLIN = External Clockl200600kHzRMODE/PLLINMODE/PLLIN Input Resistance220k IFREQF requency Setting Current81012 APGOOD OutputVPGLPGOOD Voltage LowIPGOOD = Leakage CurrentVPGOOD = 5V 1 AVPGPGOOD Trip LevelVFB with Respect to Set Output Voltage VFB Ramping Negative VFB Ramping Positive 10 10 % %Note 1.

9 Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and 2: The LTC3789 is tested under pulse load conditions such that TJ TA. The LTC3789E is guaranteed to meet performance specifications from 0 C to 85 C operating junction temperature. Specifications over the 40 C to 125 C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The LTC3789I is guaranteed to meet performance specifications over the full 40 C to 125 C operating junction temperature 3: TJ is calculated from the ambient temperature TA and power dissipation PD according to the following formula: LTC3789GN: TJ = TA + (PD 80 C/W) LTC3789 UFD: TJ = TA + (PD 34 C/W)Note 4: The LTC3789 is tested in a feedback loop that servos VITH to a specified voltage and measures the resultant 5: Dynamic supply current is higher due to the gate charge being delivered at the switching frequency.

10 See the Applications Information 6: Do not apply a voltage or current to these pins. They must be connected to capacitive loads only, otherwise permanent damage may more information perForMance characTerisTicsEfficiency vs Output Current ( boost Region) efficiency vs Output Current ( buck - boost Region) efficiency vs Output Current ( buck Region) efficiency vs VINI nternal LDO Line RegulationEXTVCC LDO Line RegulationINTVCC and EXTVCC Switch Voltage vs TemperatureSupply Current vs Input VoltageRUN Pin Threshold vs TemperatureTA = 25 C unless otherwise CURRENT (mA)1040 efficiency (%)506070801001000100003020100901003789 G01 VIN = 6 VVOUT = 12 VDCMFCMDCMFCMCIRCUIT OF FIGURE 13 LOAD CURRENT (mA)1040 efficiency (%)506070801001000100003020100901003789 G02 VIN = 12 VVOUT = 12 VDCMFCMCIRCUIT OF FIGURE 13 LOAD CURRENT (mA)