LTC4012IUF-3#PBF Linear Technology, LTC4012IUF-3#PBF Datasheet

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... Portable Instruments n Battery Backup Systems n L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5723970. Typical applicaTion ...

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... LEAD FREE FINISH TAPE AND REEL LTC4012CUF-3#PBF LTC4012CUF-3#TRPBF LTC4012IUF-3#PBF LTC4012IUF-3#TRPBF Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: ...

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T SYMBOL PARAMETER Charge Voltage Regulation V V Accuracy (See Test Circuits) TOL BAT I V Input Bias Current VFB FB R FBDIV On Resistance ON I FBDIV Output Leakage Current LEAK-FBDIV ...

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LTC4012-3 elecTrical characTerisTics temperature range, otherwise specifications are at T SYMBOL PARAMETER INTV Regulator DD INTV Output Voltage DD ∆V Load Regulation DD I Short-Circuit Current (Note 5) DD Switching Regulator V AC Present Charge Enable Threshold Voltage ACP I ...

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Typical perForMance characTerisTics (T = 25°C unless otherwise noted IHLP-2525 6.8µH) A Efficiency at DCIN = 20V, BAT = 8V 100 R = 33m SENSE R = 3.01k IN 95 EFFICIENCY 90 POWER LOSS ...

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LTC4012-3 Typical perForMance characTerisTics (T = 25°C unless otherwise noted IHLP-2525 6.8µH) A Charge Current Accuracy –1 –2 DCIN = 12V R = 26.7k PROG –3 –4 –5 – ...

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Typical perForMance characTerisTics (T = 25°C unless otherwise noted IHLP-2525 6.8µH) A PWM Frequency vs Duty Cycle 600 500 400 300 200 100 DUTY CYCLE (%) Battery Shutdown Current 25 DC1256-CLASS 20 APPLICATION ...

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LTC4012-3 pin FuncTions CLN (Pin 1): Adapter Input Current Limit Negative Input. The LTC4012-3 senses voltage on this pin to determine if less charge current should be sourced to limit total input current. The threshold is set 100mV below the ...

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FuncTions BGATE (Pin 16): External Synchronous NFET Gate Control Output. This output provides gate drive to an external NMOS power transistor switch used for synchronous rectification to increase efficiency in the step-down DC/DC converter. Operating voltage is GND to ...

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LTC4012-3 block DiagraM DCIN 4 – INFET CLP 2 CLN 1 ICL 8 CHRG SHUTDOWN SHUTDOWN SHDN 6 CONTROL TO INTERNAL GND CIRCUITS 5 BAT 11 OSCILLATOR ACP FBDIV 10 0 INPUT CURRENT ...

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TesT circuiTs LTC4012-3 FROM ICL (CLP = CLN) – – EA – + 1.2085V PROG 1.2085V TARGET LTC1055 – LTC4012-3 ITH 12 0.6V 4012-3 TC01 40123fb  ...

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LTC4012-3 operaTion Overview The LTC4012 synchronous step-down (buck) cur- rent mode PWM battery charger controller. The maximum charge current is programmed by the combination of a charge current sense resistor (R SENSE resistors (R , Figure 1), and ...

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LTC4012-3 CLP CLOCK 2 OSCILLATOR BAT 11 Bulk Charge When soft-start is complete, the LTC4012-3 begins sourc- ing the current programmed by the external components connected to CSP , CSN and PROG. Some batteries may require a small conditioning ...

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LTC4012-3 operaTion Adapter Input Current Limit The LTC4012-3 can monitor and limit current from the input DC supply, which is normally an AC adapter. When the programmed adapter input current is reached, charge current is reduced to maintain the desired ...

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The ITH output of the error amplifier is a scaled control voltage for one input of the PWM comparator, CC. ITH sets a peak inductor current threshold, sensed by R1, to maintain the desired average current through R current ...

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LTC4012-3 applicaTions inForMaTion Programming Charge Current The formula for charge current is:  2085 . • –   CHRG R R SENSE PROG The LTC4012-3 operates best with 3.01k input resistors, ...

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The value of R controls the maximum value of charge PROG current which can be programmed (Q1 continuously on). PWM of the Q1 gate voltage changes the value produce lower currents. The frequency of this ...

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LTC4012-3 applicaTions inForMaTion Programming Input Current Limit To set the input current limit, I LIM adapter current rating must be known. To account for the tolerance of the LTC4012-3 input current sense circuit, 5% should be subtracted from the adapter’s ...

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The overall accuracy of this circuit needs to be better than the power source current tolerance or be margined such that the worse-case error remains under the power source limits. The accuracy of the Figure 7 circuit is ...

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LTC4012-3 applicaTions inForMaTion C/10 CHRG Indicator The value chosen for R has a strong influence on PROG charge current monitoring and the accuracy of the C/10 charge indicator output (CHRG). The LTC4012-3 uses the voltage on the PROG pin to ...

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The output capacitor shown across the battery and ground must also absorb PWM output ripple current. The general formula for this capacitor current is:   V BAT • V • 1 –   ...

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LTC4012-3 applicaTions inForMaTion R should not be less than 2.37k or more than 6.04k. Val- IN ues of R greater than 3.01k may cause some reduction in IN programmed current accuracy. Use these equations and guidelines, as represented in Table ...

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FET Selection Two external power MOSFETs must be selected for use with the charger: an N-channel power switch (top FET) and an N-channel synchronous rectifier (bottom FET). Peak gate-to-source drive levels are internally set to about 5V. Consequently, ...

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LTC4012-3 applicaTions inForMaTion The LTC4012-3 can be soft-started with the compensation capacitor on the ITH pin. At start-up, ITH will quickly rise to about 0.25V, then ramp rate set by the com- pensation capacitor and the 40µA ...

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Place the inductor input as close as possible to the switching FETs. Minimize the surface area of the switch node. Make the trace width the minimum needed to support the programmed charge current. Use no cop- per ...

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LTC4012-3 package DescripTion 4.50 ± 0.05 3.10 ± 0.05 2.45 ± 0.05 2.00 REF 2.45 ± 0.05 RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 4.00 ± 0.10 PIN 1 TOP MARK (NOTE ...

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... I-Grade Part Added. Reflected Throughout the Data Sheet 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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. ...

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... SCHOTTKY DIODE D5 OR THE COMBINATION OF R14 AND Q4 L1 4.7µH D3: CMDSH-3 D4: MBR230LSFT1 Q1: 2N7002 Q2, Q3: Si7218DN Q4, Q5: Si7423DN R11 L1: 1HLP-2525CZER4R7M11 25m *: SEE TGATE BOOST SUPPLY IN APPLICATIONS INFORMATION + 12.6V Li-Ion BATTERY 40123 TA03 TM package LT 0610 REV B • PRINTED IN USA  LINEAR TECHNOLOGY CORPORATION 2009 40123fb ...