LTC3642 Linear Technology, LTC3642 Datasheet
LTC3642
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LTC3642 Summary of contents
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... DC supply current at no load while maintaining output voltage regulation. The LTC3642 can supply up to 50mA load current and features a programmable peak current limit that provides a simple method for optimizing effi ciency in lower current applications. The LTC3642’ ...
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... LTC3642IMS8E-3.3E#PBF LTC3642IMS8E-3.3#TRPBF LTC3642IMS8E-5#PBF LTC3642IMS8E-5#TRPBF LTC3642EDD#PBF LTC3642EDD#TRPBF LTC3642EDD-3.3#PBF LTC3642EDD-3.3#TRPBF LTC3642EDD-5#PBF LTC3642EDD-5#TRPBF LTC3642IDD#PBF LTC3642IDD#TRPBF LTC3642IDD-3.3#PBF LTC3642IDD-3.3#TRPBF LTC3642IDD-5#PBF LTC3642IDD-5#TRPBF Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi label on the shipping container. ...
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... Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTC3642E is guaranteed to meet specifi cations from 0°C to 85°C with specifi cations over the –40°C to 125°C operating junction temperature range assured by design, characterization and correlation with statistical process controls. The LTC3642I is guaranteed to meet specifi ...
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... LTC3642 www.DataSheet4U.com TYPICAL PERFORMANCE CHARACTERISTICS Effi ciency vs Load Current 100 FIGURE 10 CIRCUIT I OPEN 95 SET V = 10V OUT 15V 45V 24V 36V 0 LOAD CURRENT (mA) Feedback Comparator Voltage vs Temperature 0.801 V = 10V IN 0.800 0.799 0.798 –40 – ...
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... TEMPERATURE (°C) 3642 G13 Operating Waveforms OUTPUT VOLTAGE 50mV/DIV SWITCH VOLTAGE 5V/DIV INDUCTOR CURRENT 50mA/DIV 4632 G16 V = 10V 10μs/DIV IN I OPEN SET FIGURE 10 CIRCUIT LTC3642 Switch Leakage Current vs Temperature 0 45V IN 0.5 0.4 0.3 0.2 0 110 –40 – TEMPERATURE (°C) 3642 G11 Internal Soft-Start Time vs Temperature 1 ...
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... A 5μA current is sourced out of this pin. If left fl oating, the ramp time defaults to an internal 0.75ms soft-start. RUN (Pin 5): Run Control Input. A voltage on this pin above 1.2V enables normal operation. Forcing this pin below 0.7V shuts down the LTC3642, reducing quiescent current to approximately 3μ (Pin 6): Output Voltage Feedback. For the fi ...
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... THROUGH PREVENTION + REVERSE CURRENT – COMPARATOR VOLTAGE REFERENCE FEEDBACK + COMPARATOR 0.800V + – PART NUMBER R1 R2 LTC3642 0 LTC3642-3.3 2.5M 800k LTC3642-5 4.2M 800k LTC3642 OUT C1 5μ OUT 3642 BD R2 IMPLEMENT DIVIDER EXTERNALLY FOR ADJUSTABLE VERSION 3642f ...
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... LTC3642 inherently switches at a lower frequency during start-up or short-circuit conditions. Start-Up and Shutdown If the voltage on the RUN pin is less than 0.7V, the LTC3642 enters a shutdown mode in which all internal circuitry is FB disabled, reducing the DC supply current to 3μA. When the voltage on the RUN pin exceeds 1 ...
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... I pin to ground. The 1μA current sourced out SET of this pin through the resistor generates a voltage that is translated into an offset in the peak current comparator, which limits the peak inductor current. pin SET LTC3642 3642f 9 ...
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... LTC3642 www.DataSheet4U.com APPLICATIONS INFORMATION The basic LTC3642 application circuit is shown on the front page of this data sheet. External component selection is determined by the maximum load current requirement and begins with the selection of the peak current programming resistor The inductor value L can then be determined, ...
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... MOSFET. To prevent large ripple voltage, a low ESR input capacitor sized for the maximum RMS current should be used. Approximate RMS current is given by: 100 3642 F04 I RMS LTC3642 Selection OUT , is needed to fi lter the trapezoidal OUT − ...
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... OUT current and stores energy to satisfy the load current when the LTC3642 is in sleep. The output voltage ripple during a burst cycle is dominated by the output capacitor equivalent series resistance (ESR) and can be estimated by the following equation: ...
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... Characteristics table. The current that fl ows through this divider will directly add to the shutdown, sleep and active current of the LTC3642, and care should be taken to minimize the impact of this current on the overall effi ciency of the application circuit. Resistor values in the megohm range may be required to keep the impact on quiescent shutdown and sleep currents low ...
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... μA When the LTC3642 detects a fault condition (input supply undervoltage or overvoltage) or when the RUN pin falls below 1.1V, the SS pin is quickly pulled to ground and the internal soft-start timer is reset. This ensures an orderly restart when using an external soft-start capacitor. The duration of the 1ms internal peak current soft-start may be increased by placing a capacitor from the I to ground ...
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... Thermal Considerations The LTC3642 does not dissipate much heat due to its high effi ciency and low peak current level. Even in worst-case conditions (high ambient temperature, maximum peak current and high duty cycle), the junction temperature will exceed ambient temperature by only a few degrees ...
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... PC Board Layout Checklist When laying out the printed circuit board, the following checklist should be used to ensure proper operation of the LTC3642. Check the following in your layout: 1. Large switched currents fl the power switches and input capacitor. The loop formed by these compo- nents should be as small as possible ...
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... GND SET 33k C : TDK C3225X7R1H105KT AVX 08056D106KAT2A OUT L1: MURATA LQH32CN471K23 L1 4700μH V OUT 15V 10mA R1 C OUT 3M 4.7μF R2 169k 3642 TA07a LTC3642 Maximum Load Current vs Input Voltage –3V OUT –5V 40 OUT –12V OUT ...
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... LTC3642 www.DataSheet4U.com PACKAGE DESCRIPTION 3.5 0.05 1.65 0.05 2.15 0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS TOP MARK (NOTE Package 8-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1698) 0.675 0.05 PACKAGE OUTLINE 0.25 0.05 0.50 BSC 2.38 0.05 (2 SIDES) 3.00 0.10 (4 SIDES) PIN 1 0.75 0.05 0.200 REF 0.00 – 0.05 NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1) 2 ...
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... DETAIL “A” (.193 ± .006) 0° – 6° TYP 0.53 ± 0.152 (.021 ± .006) (.043) DETAIL “A” SEATING PLANE 0.22 – 0.38 (.009 – .015) TYP LTC3642 BOTTOM VIEW OF EXPOSED PAD OPTION 2.06 ± 0.102 (.081 ± .004) 1 1.83 ± 0.102 (.072 ± .004) 8 0.52 (.0205) 8 ...
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... Linear Technology Corporation 20 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● 5V, 50mA Regulator for Automotive Applications L1 220μH V BATT 12V LTC3642 1μF 470k RUN SET 88.7k SS HYST 3642 TA06a GND C : TDK C3225X7R2A105M KEMET C1210C106K4RAC ...