LTC3780EG Linear Technology, LTC3780EG Datasheet
LTC3780EG
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LTC3780EG Summary of contents
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... A Power Good output pin indicates when the output is within 7.5% of its designed set point. , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. ...
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... Operating Temperature Range (Note 7) LTC3780E ........................................... – 40°C to 85°C LTC3780I ............................................ – 40°C to 85°C Junction Temperature (Note 2) ............................ 125°C Storage Temperature Range .................. –65°C to 125°C Lead Temperature (Soldering, 10 sec) SSOP Only ........................................................ 300° ORDER PART NUMBER LTC3780EG LTC3780IG SENSE 1 – SENSE ...
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ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T SYMBOL PARAMETER V Reference Voltage Line Regulation REF(LINEREG) g Error Amplifier Transconductance m(EA) g Error Amplifier GBW m(GBW) I Input DC Supply Current Q Normal Standby Shutdown Supply Current V Forced ...
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LTC3780 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T SYMBOL PARAMETER t Minimum On-Time for Main Switch in ON(MIN,BOOST) Boost Operation t Minimum On-Time for Synchronous ON(MIN,BUCK) Switch in Buck Operation Internal V Regulator CC V Internal V Voltage ...
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W U TYPICAL PERFOR A CE CHARACTERISTICS Efficiency vs Output Current (Boost Operation) 100 BURST 90 DCM 80 70 CCM 12V OUT 40 0.01 0 (A) LOAD 3780 G01 ...
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LTC3780 W U TYPICAL PERFOR A CE CHARACTERISTICS Discontinuous Current Mode (DCM 6V 12V) IN OUT SW2 10V/DIV SW1 10V/DIV V OUT 100mV/DIV I L 2A/DIV 3780 G10 5µs/DIV 12V ...
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W U TYPICAL PERFOR A CE CHARACTERISTICS Oscillator Frequency vs Temperature 450 400 V = 2.4V PLLFLTR 350 V = 1.2V PLLFLTR 300 250 PLLFLTR 200 150 100 50 0 –50 – 100 ...
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LTC3780 W U TYPICAL PERFOR A CE CHARACTERISTICS Load Step V OUT 500mV/DIV I L 5A/DIV 3780 G27 V = 18V 200µs/DIV 12V OUT LOAD STEP CONTINUOUS MODE Line Transient V IN 10V/DIV V ...
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CTIO S (SSOP/QFN) V (Pin 6/Pin 4): Error Amplifier Feedback Input. This OSENSE pin connects the error amplifier input to an external resis- tor divider from V . OUT SGND (Pin 7/Pin 5): Signal Ground. ...
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LTC3780 W BLOCK DIAGRA STBYMD FCB 1.2V 4 1.2µA SS RUN 100k 5.7V – EXTV CC INTV SGND 10 FCB I LIM + BUCK LOGIC – I REV + – ...
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U OPERATIO MAIN CONTROL LOOP The LTC3780 is a current mode controller that provides an output voltage above, equal to or below the input voltage. The LTC proprietary topology and control architecture employs a current-sensing resistor in Buck or Boost ...
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LTC3780 U OPERATIO and Switch A is turned on for the remainder of the cycle. Switches A and B will alternate, behaving like a typical synchronous buck regulator. The duty cycle of switch A increases until the maximum duty cycle ...
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U OPERATIO The duty cycle of Switch C decreases until the minimum duty cycle of the converter in Buck mode reaches D , given by: MIN_BOOST • 100% MIN_BOOST BUCK-BOOST where D is the duty cycle ...
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LTC3780 U OPERATIO diode of Synchronous Switch B or the Schottky diode, which is in parallel in with Synchronous Switch B, is used to discharge inductor current result, some cycles will be skipped when the output load current ...
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U OPERATIO OUTPUT OVERVOLTAGE PROTECTION An overvoltage comparator guards against transient over- shoots (>7.5%) as well as other more serious conditions that may overvoltage the output. In this case, Synchro- nous Switch B and Synchronous Switch D are turned on ...
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LTC3780 U U APPLICATIO S I FOR ATIO Figure basic LTC3780 application circuit. External component selection is driven by the load requirement, and begins with the selection of R SENSE value. Next, the power MOSFETs are selected. ...
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U U APPLICATIO S I FOR ATIO Inductor Selection The operating frequency and inductor selection are inter- related in that higher operating frequencies allow the use of smaller inductor and capacitor values. The inductor value has a direct effect on ...
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LTC3780 U U APPLICATIO S I FOR ATIO (Switch B and C shown in Figure 1). Important parameters for the power MOSFETs are the breakdown voltage V threshold voltage V , on-resistance R GS,TH transfer capacitance C and maximum current ...
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U U APPLICATIO S I FOR ATIO The used in the equation normally includes TH(JA) the R for the device plus the thermal resistance from TH(JC) the case to the ambient temperature ( can then ...
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LTC3780 U U APPLICATIO S I FOR ATIO EXTV Connection CC The LTC3780 contains an internal P-channel MOSFET switch connected between the EXTV When the voltage applied to EXTV CC internal regulator is turned off and a switch connects the ...
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U U APPLICATIO S I FOR ATIO The Standby Mode (STBYMD) Pin Function The Standby mode (STBYMD) pin provides several choices for start-up and standby operational modes. If the pin is pulled to ground, the SS pin is internally pulled ...
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LTC3780 U U APPLICATIO S I FOR ATIO In Buck mode, maximum sense voltage and the sense resistance determines the maximum allowed inductor valley current, which is: 130 MAX BUCK ( , ) R SENSE To ...
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U U APPLICATIO S I FOR ATIO Tie the PLLFLTR pin to INTV for 400kHz operation. The CC inductance value is chosen first based on a 30% ripple current assumption. In Buck mode, the ripple current is ⎛ ...
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LTC3780 U U APPLICATIO S I FOR ATIO A low ESR (10mΩ) capacitor is selected. Input voltage ripple is 65mV chosen to filter the square current in Boost mode. OUT In this mode, the maximum output current peak ...
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U U APPLICATIO S I FOR ATIO • Connect the INTV decoupling capacitor close to the CC IC, between the INTV and the power ground pins. CC This capacitor carries the MOSFET drivers’ current ...
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LTC3780 PACKAGE DESCRIPTIO 7.8 – 8.2 0.42 ±0.03 RECOMMENDED SOLDER PAD LAYOUT 5.00 – 5.60** (.197 – .221) 0.09 – 0.25 0.55 – 0.95 (.0035 – .010) (.022 – .037) NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS MILLIMETERS 2. DIMENSIONS ARE IN ...
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... DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights Package 32-Lead Plastic QFN (5mm × ...
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... OUT ≤ 60V, 0.1Ω Saturation Switch, 16-Pin SSOP IN ≤ 60V, 500mA Switch, Automatic Step-Up/Step-Down, ≤ 5.5V, 96% Efficiency, 600kHz Operation, 2A Switch IN LT/TP 0305 500 • PRINTED IN THE USA © LINEAR TECHNOLOGY CORPORATION 2005 V OUT 12V 5A ≤ 20A ≤ 20A ≤ 20A ...