LTC1735CGN-1 Linear Technology, LTC1735CGN-1 Datasheet

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... Power Supply for Mobile Pentium TM SpeedStep Technology Cellular Telephones and Wireless Modems , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode and OPTI-LOOP are trademarks of Linear Technology Corporation. Pentium is a registered trademark of Intel Corporation. SpeedStep is a trademark of Intel Corporation. U TYPICAL APPLICATIO ...

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... OSENSE V = 4.5V RUN/SS Measured at V Pin (Ramping Negative 0.7V OSENSE – SENSE SENSE Tested with a Square Wave (Note ORDER PART TOP VIEW NUMBER BOOST LTC1735CGN LTC1735CS LTC1735IGN INTV CC LTC1735IS PGND GN PART 9 8 EXTV CC MARKING S PACKAGE 16-LEAD PLASTIC SO 17351 = 130 C/W (GN) ...

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... J dissipation P according to the following formulas: D LTC1735CS-1, LTC1735IS- LTC1735CGN-1, LTC1735IGN- Note 3: The LTC1735-1 is tested in a feedback loop that servos V to the balance point for the error amplifier (V ITH Note 4: The minimum on-time condition corresponds to an inductor peak-to-peak ripple current > 40 (see Minimum On-Time MAX Considerations in the Applications Information section) ...

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LTC1735 TYPICAL PERFOR A CE CHARACTERISTICS Efficiency vs Load Current (3 Operating Modes) 100 EXTV OPEN CC 90 BURST 80 SYNC 70 CONT 10V 3.3V OUT 0.01 ...

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W U TYPICAL PERFOR A CE CHARACTERISTICS Maximum Current Sense Threshold vs Normalized Output Voltage (Foldback 100 NORMALIZED OUTPUT VOLTAGE (%) 1735-1 G10 Maximum Current Sense Voltage ...

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LTC1735 TYPICAL PERFOR A CE CHARACTERISTICS Oscillator Frequency vs Temperature 300 C = 47pF OSC 290 280 270 260 250 60 135 –40 – 110 TEMPERATURE ( C) 1735-1 G19 Start-Up V OUT 1V/DIV V ...

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CTIO S C (Pin 1): External capacitor C OSC ground sets the operating frequency. RUN/SS (Pin 2): Combination of Soft-Start and Run Control Inputs. A capacitor to ground at this pin sets the ramp time ...

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LTC1735 CTIO AL DIAGRA INTV CC C OSC 100k PGOOD SGND 8 OSC OSC – + 0.74V OV + – 0.86V V OSENSE V g =1. – 0.8V R1 ...

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U OPERATIO (Refer to Functional Diagram) The main control loop is shut down by pulling Pin 2 (RUN/ SS) low. Releasing RUN/SS allows an internal 1.2 A current source to charge soft-start capacitor C C reaches 1.5V, the main control ...

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LTC1735-1 U OPERATIO (Refer to Functional Diagram) POWER GOOD A window comparator monitors the output voltage and its open-drain output is pulled low when the divided down output voltage (appearing at the V OSENSE 7.5% of the reference voltage of ...

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U U APPLICATIO S I FOR ATIO The value calculated from the desired operating OSC frequency assuming no external clock input on the PGOOD pin – ...

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LTC1735 APPLICATIO S I FOR ATIO Inductor Core Selection Once the value for L is known, the type of inductor must be selected. High efficiency converters generally cannot afford the core loss found in low cost powdered iron ...

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U U APPLICATIO S I FOR ATIO MOSFET from turning on and storing charge during the dead-time, which could cost as much efficiency Schottky is generally a good size for 10A to 12A regu- lators ...

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LTC1735 APPLICATIO S I FOR ATIO Manufacturers such as Nichicon, United Chemicon and Sanyo can be considered for high performance through- hole capacitors. The OS-CON semiconductor dielectric capacitor available from Sanyo has the lowest (ESR)(size) product of any ...

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U U APPLICATIO S I FOR ATIO Significant efficiency gains can be realized by powering INTV from the output, since the V CC from the driver and control currents will be scaled by a factor of (Duty Cycle)/(Efficiency). For 5V ...

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LTC1735 APPLICATIO S I FOR ATIO When adjusting the gate drive level, the final arbiter is the total input current for the regulator. If you make a change and the input current decreases, then you improved the efficiency. ...

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U U APPLICATIO S I FOR ATIO current used as a short-circuit timer. If the output SS voltage falls to less than 70% of its nominal output voltage after C reaches 4.1V, the assumption is made that the ...

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LTC1735 APPLICATIO S I FOR ATIO Minimum On-Time Considerations Minimum on-time t is the smallest amount of time ON(MIN) that the LTC1735-1 is capable of turning the top MOSFET on and off again determined by internal ...

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U U APPLICATIO S I FOR ATIO Table 1 PGOOD PIN CONDITION DC Voltage 0.7V No Power Good Indication Burst Mode Operation Disabled/Forced Continuous Current Reversal Enabled Resistor Pull-Up to Power Good Indication INT (or Other DC Burst ...

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LTC1735 APPLICATIO S I FOR ATIO Other “hidden” losses such as copper trace and internal battery resistances can account for an additional 5% to 10% efficiency degradation in portable systems very important to include these “system” ...

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... C9, C19: TAIYO YUDEN JMK107BJ105 C10: KEMET T494A475M010AS C12 TO C14: TAIYO YUDEN GMK325F106 16 Q1 C15 TO C18: PANASONIC EEFUE0G181R FDS6680A D1: CENTRAL SEMI CMDSH-3 D2: MOTOROLA MBRS340 15 L1: PANASONIC ETQP6F1R0SA Q1 TO Q3: FAIRCHILD FDS6680A C8 R5: IRC LRF2512-01-R003-J 0. U1: LINEAR TECHNOLOGY LTC1735CS CMDSH MBRS340 Q2 FDS6680A + C10 ...

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LTC1735 APPLICATIO S I FOR ATIO The next step is to calculate the I pin voltage factor. The V scale factor reflects the I ITH required for a given load current in continuous inductor current operation. ...

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U U APPLICATIO S I FOR ATIO Resistor R1 is • • ITH Unfortunately, PCB noise can add to the voltage ...

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LTC1735 APPLICATIO S I FOR ATIO Design Example As a design example, assume V = 12V (nominal 22V (max 1.5V 12A and f = 300kHz, OUT MAX R and C can immediately ...

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U U APPLICATIO S I FOR ATIO LTC1735-1. The V line should not be routed OSENSE close to any other nodes with high slew rates. + – 3. Are the SENSE and SENSE leads routed together with minimum PC trace ...

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LTC1735-1 U TYPICAL APPLICATIONS INTV CC C 100k OSC 43pF 1 C OSC RUN/ 470pF 33k POWER C 220pF PGOOD C2 GOOD 5 SENSE 1000pF 6 SENSE ...

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... FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 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. ...

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... LTC1736 High Efficiency Synchronous Step-Down Controller with 5-Bit VID Control LTC1772 SOT-23 High Efficiency Constant Frequency Step-Down Controller Adaptive Power and PolyPhase are trademarks of Linear Technology Corporation. Linear Technology Corporation 28 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear-tech.com ...