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Numéro de sérieLTC3608
CategoriePower Management => DC-DC Converters => Step-down
Description18V, 8A Monolithic Synchronous Step-Down DC/DC Converter
The LTC®3608 is a high efficiency, monolithic synchronous step-down DC/DC converter that can deliver up to 8A output current from a 4V to 18V (20V maximum) input supply. It uses a valley current control architecture to deliver very low duty cycle operation at high frequency with excellent transient response. The operating frequency is selected by an external resistor and is compensated for variations in VIN and VOUT.
SociétéLinear Technology Corporation
DatasheetTélécharger LTC3608 datasheet
 
 
  • Description courte
  • FEATURES
    18V, 8A Monolithic Synchronous Step-Down DC/DC Converter DESCRIPTION

    The is a high efficiency, monolithic synchronous step-down DC/DC converter that can deliver to 8A output current from 18V (20V maximum) input supply. It uses a valley current control architecture to deliver very low duty cycle operation at high frequency with excellent transient response. The operating frequency is selected by an external resistor and is compensated for variations in VIN and VOUT. The LTC3608 can be configured for discontinuous or forced continuous operation at light load. Forced continuous operation reduces noise and RF interference while discontinuous mode provides high efficiency by reducing switching losses at light loads. Fault protection is provided by internal foldback current limiting, an output overvoltage comparator and an optional short-circuit shutdown timer. Soft-start capability for supply sequencing is accomplished using an external timing capacitor. The regulator current limit is user programmable. A power good output voltage monitor indicates when the output is in regulation. The LTC3608 is available in a compact × 8mm QFN package.

    8A Output Current Wide VIN Range to 18V Internal N-Channel MOSFETs True Current Mode Control Optimized for High Step-Down Ratios tON(MIN) 100nsec Extremely Fast Transient Response Stable with Ceramic COUT ±1% 0.6V Voltage Reference Power Good Output Voltage Monitor Adjustable On-Time/Switching Frequency Adjustable Current Limit Programmable Soft-Start Output Overvoltage Protection Optional Short-Circuit Shutdown Timer Low Shutdown IQ: 15A Available 8mm 52-Lead QFN Package

    APPLICATIONS
    Point of Load Regulation Distributed Power Systems

    L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including

    0.1F VOUT 187k VON RUN/SS 1500pF 11.3k ITH SGND BOOST INTVCC FCB VRNG PGOOD EXTVCC PGND VFB

    100 10000 EFFICIENCY 1000 POWER LOSS (mW) VIN 95 90 EFFICIENCY VOUT 2.5V 8A VIN = 12V VOUT = 2.5V EXTVCC 0.1 1 LOAD CURRENT (A) POWER LOSS 10 100

    TOP VIEW 52 PVIN 51 PVIN 50 PVIN 49 PVIN 48 PVIN 41 SW

    Input Supply Voltage (SVIN, PVIN, ION)....... to ­0.3V Boosted Topside Driver Supply Voltage (BOOST)................................................ ­0.3V SW Voltage............................................... to ­5V INTVCC, EXTVCC, (BOOST ­ SW), RUN/SS, PGOOD Voltages...................................... to ­0.3V FCB, VON, VRNG Voltages............ INTVCC to ­0.3V ITH, VFB Voltages....................................... to ­0.3V Operating Junction Temperature Range (Notes to 125°C Storage Temperature Range................... to 125°C

    PVIN 1 PVIN 2 PVIN 3 PVIN 4 PVIN 5 PVIN 6 PVIN NC 9 SGND 10 BOOST 11 RUN/SS 12 VON 13 SGND 14 54 SGND 53 PVIN

    40 PGND 39 PGND 38 PGND SW 37 PGND 36 PGND 35 PGND 34 PGND SW 32 INTVCC 31 INTVCC 30 SVIN 29 EXTVCC NC 27 SGND

    LEAD FREE FINISH LTC3608EWKG#PBF LTC3608IWKG#PBF TAPE AND REEL LTC3608EWKG#TRPBF LTC3608IWKG#TRPBF PART MARKING* LTC3608WKG PACKAGE DESCRIPTION × 8mm) Plastic QFN × 8mm) Plastic QFN TEMPERATURE RANGE to 125°C

    Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/

    SYMBOL Main Control Loop SVIN IQ Operating Input Voltage Range Input DC Supply Current Normal Shutdown Supply Current Feedback Reference Voltage Feedback Voltage Line Regulation Feedback Voltage Load Regulation Feedback Input Current Error Amplifier Transconductance Forced Continuous Threshold Forced Continuous Pin Current On-Time Minimum On-Time Minimum Off-Time Maximum Valley Current Maximum Reverse Valley Current Output Overvoltage Fault Threshold RUN Pin Start Threshold RUN Pin Latchoff Enable Threshold RUN Pin Latchoff Threshold Soft-Start Charge Current Soft-Start Discharge Current Undervoltage Lockout Undervoltage Lockout Release Top Switch On-Resistance Bottom Switch On-Resistance Internal VCC Voltage Internal VCC Load Regulation EXTVCC Switchover Voltage EXTVCC Switch Drop Voltage EXTVCC Switchover Hysteresis PGOOD Upper Threshold PGOOD Lower Threshold PGOOD Hysteresis PGOOD Low Voltage VFB Rising VFB Falling VFB Returning IPGOOD 6V < VIN < 18V, VEXTVCC = 4V ICC to 20mA, VEXTVCC = 4V ICC = 20mA, VEXTVCC Rising ICC = 20mA, VEXTVCC = 5V

    The l denotes the specifications which apply over the full operating junction temperature range, otherwise specifications are = 25°C. VIN = 15V unless otherwise noted.

    PARAMETER CONDITIONS MIN 900 15 ITH to 85°C (Note 3) ITH to 125°C (Note 3) VIN to 18V, ITH = 1.2V (Note 3) ITH to 1.9V (Note 3) VFB = 0.6V ITH = 1.2V (Note 3) VFCB = 0.6V ION = 60A, VON = 1.5V ION = 60A, VON = 0V ION = 180A, VON = 0V ION = 30A, VON = 1.5V VRNG = 0.5V, VFB = 0.56V, FCB = 0V VRNG = 0V, VFB = 0.56V, FCB = 0V VRNG = 0.5V, VFB = 0.64V, FCB = 0V VRNG = 0V, VFB = 0.64V, FCB = 0V

    VFB VFB(LINEREG) VFB(LOADREG) IFB gm(EA) VFCB IFCB tON tON(MIN) tOFF(MIN) IVALLEY(MAX) IVALLEY(MIN) VFB(OV) VRUN/SS(ON) VRUN/SS(LE) VRUN/SS(LT) IRUN/SS(C) IRUN/SS(D) VIN(UVLO) VIN(UVLOR) RDS(ON)

    RUN/SS Pin Rising RUN/SS Pin Falling VRUN/SS = 0V VRUN/SS = 4.5V, VFB = 0V INTVCC Falling INTVCC Rising

    Internal VCC Regulator VINTVCC VLDO(LOADREG) VEXTVCC VEXTVCC(HYS) PGOOD Output VFBH VFBL VFB(HYS) VPGL V