LTC3786 LINER [Linear Technology], LTC3786 Datasheet
LTC3786
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LTC3786 Summary of contents
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FeaTures Wide V Range: 5.5V to 36V Operation n IN 2-Phase Operation Reduces Input and Output n Capacitance Fixed Frequency, Peak Current Mode Control n Internal 10V LDO Regulator n Lower UVLO Thresholds Allows the Use of n MOSFETs Rated ...
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LTC3862-2 absoluTe MaxiMuM raTings Input Supply Voltage (V ) ......................... –0.3V to 40V IN INTV Voltage ..........................................–0.3V to 11V CC INTV LDO RMS Output Current .........................50mA CC RUN Voltage................................................. –0. SYNC Voltage ............................................... –0. SLOPE, PHASEMODE, ...
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LEAD FREE FINISH TAPE AND REEL LTC3862EFE-2#PBF LTC3862EFE-2#TRPBF LTC3862IFE-2#PBF LTC3862IFE-2#TRPBF LTC3862HFE-2#PBF LTC3862HFE-2#TRPBF LTC3862EGN-2#PBF LTC3862EGN-2#TRPBF LTC3862IGN-2#PBF LTC3862IGN-2#TRPBF LTC3862HGN-2#PBF LTC3862HGN-2#TRPBF LTC3862EUH-2#PBF LTC3862EUH-2#TRPBF LTC3862IUH-2#PBF LTC3862IUH-2#TRPBF LTC3862HUH-2#PBF LTC3862HUH-2#TRPBF Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade ...
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LTC3862-2 elecTrical characTerisTics specified operating junction temperature range, otherwise specifications are at T otherwise noted. SYMBOL PARAMETER V Error Amplifier Maximum Output Voltage ITH (Internally Clamped) Error Amplifier Minimum Output Voltage I Error Amplifier Output Source Current ITH Error Amplifier ...
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T otherwise noted. SYMBOL PARAMETER t Minimum On-Time ON(MIN)1 t Minimum On-Time ON(MIN)2 t Minimum On-Time ON(MIN)3 Gate Driver R Driver Pull-Up R DS(ON) DS(ON) Driver Pull-Down R DS(ON) ...
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LTC3862-2 Typical perForMance characTerisTics Efficiency vs Output Current 80V OUT 12V 24V ...
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Typical perForMance characTerisTics INTV vs Temperature CC 10.05 10.04 10.03 10.02 10.01 10.00 9.99 9.98 9.97 9.96 9.95 – –25 0 100 125 TEMPERATURE (°C) 38622 G10 Feedback Voltage vs Temperature 1.235 1.233 1.231 1.229 1.227 1.225 ...
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LTC3862-2 Typical perForMance characTerisTics RUN Threshold vs Input Voltage 1.5 1.4 1.3 ON 1.2 OFF 1.1 1 INPUT VOLTAGE (V) 38622 G19 RUN Source Current vs Input Voltage 0 –1 –2 –3 ...
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Typical perForMance characTerisTics Frequency vs PLLFLTR Voltage 1400 1200 1000 800 600 400 200 0 0 PLLFLTR VOLTAGE (V) 38622 G28 Minimum On-Time vs Input Voltage 430 380 BLANK = 3V8 330 BLANK = FLOAT 280 ...
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LTC3862-2 pin FuncTions 3V8: Output of the Internal 3.8V LDO from INTV pin for the low voltage analog and digital circuits. A low ESR 1nF ceramic bypass capacitor should be connected between 3V8 and SGND, as close as possible to ...
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FuncTions + + SENSE1 , SENSE2 : Positive Inputs to the Current Comparators. The ITH pin voltage programs the current comparator offset in order to set the peak current trip threshold. This pin is normally connected to a sense ...
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LTC3862-2 FuncTional DiagraM CLKOUT SYNC PLLFLTR MAX PHASEMODE FREQ R FREQ SLOPE SLOPE COMPENSATION BLANK BLANK BLOGIC LOGIC 3V8 5µ ITH PSKIP PSKIP + – ...
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The Control Loop The LTC3862-2 uses a constant frequency, peak current mode step-up architecture with its two channels operat- ing 180 degrees out-of-phase. During normal operation, each external MOSFET is turned on when the clock for that channel sets ...
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LTC3862-2 operaTion In multi-phase applications, all of the FB pins are connected together and all of the error amplifier output pins (ITH) are connected together. The INTV pins, however, should not CC be connected together. The INTV CC sourcing current ...
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To prevent the maximum junction temperature from be- ing exceeded, the input supply current to the IC should be checked when operating in continuous mode (heavy load) at maximum trade-off between the operat- IN ing frequency ...
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LTC3862-2 operaTion Operation at High Supply Voltage At high input voltages, the LTC3862-2’s internal LDO can dissipate a significant amount of power, which could cause the maximum junction temperature to be exceeded. Conditions such as a high operating frequency, or ...
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Operation of the RUN Pin The control circuitry in the LTC3862-2 is turned on and off using the RUN pin. Pulling the RUN pin below 1.22V forces shutdown mode and releasing it allows a 0.5μA current source to pull ...
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LTC3862-2 operaTion The LTC3862-2 uses a constant frequency architecture that can be programmed over a 75kHz to 500kHz range using a single resistor from the FREQ pin to ground. Figure 6 illustrates the relationship between the FREQ pin resistance and ...
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Using the LTC3862-2 Transconductance (g Amplifier in Multi-Phase Applications The LTC3862-2 error amplifier is a transconductance amplifier, meaning that it has high DC gain but high output impedance (the output of the error amplifier is a current ...
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LTC3862-2 operaTion one LTC3862-2 chip, connect all of the SS pins together and use one external capacitor to program the soft-start time. In this case, the current into the soft-start capaci- tor will • 5μA, where ...
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When excess slope compensation is applied to the internal current sense signal, the phase margin of the control loop suffers. Figure ...
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LTC3862-2 operaTion MINIMUM ON-TIME AT LIGHT LOAD WITH BLANK = SGND INDUCTOR CURRENT 200mA/DIV GATE 5V/DIV SW NODE 20V/DIV V = 36V 500ns/DIV 72V OUT MEASURED ON-TIME = 210ns MINIMUM ON-TIME AT LIGHT LOAD WITH BLANK = ...
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The SENSE and SENSE Pins + – The SENSE and SENSE pins are high impedance inputs to the CMOS current comparators for each channel. Nominally, there current into or out of these pins. There ...
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LTC3862-2 operaTion The ITH series R • C filter sets the dominant pole-zero C C loop compensation. The transfer function for boost and flyback converters contains a right half plane zero that normally requires the loop crossover frequency to be ...
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Typical Boost Applications Circuit A basic 2-phase, single output LTC3862-2 application circuit is shown in Figure 18. External component selec- tion is driven by the characteristics of the load and the input supply. Duty Cycle Considerations For a ...
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LTC3862-2 applicaTions inForMaTion Maximum Duty Cycle Limitations Another operating extreme occurs at high duty cycle, when the input voltage is low and the output voltage is high. In this case – V IN(MIN) ...
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The inductor saturation current rating needs to be higher than the worst-case peak inductor current during an overload condition the maximum rated load O(MAX) current, then the maximum current limit value (I would normally be ...
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LTC3862-2 applicaTions inForMaTion The power dissipated by the MOSFET in a multi-phase boost converter with n phases is: 2 I O(MAX • R FET DS(ON) n • 1– D MAX ...
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For a boost converter where the current limit value is chosen to be 30% higher than the maximum load current, the peak current in the MOSFET and sense resistor is: χ 1 • ...
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LTC3862-2 applicaTions inForMaTion power dissipation is important when deciding on a diode current rating, package type, and method of heat sinking close approximation, the power dissipated by the diode is • V • (1 – ...
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For the bulk capacitance, which we assume contributes 1% to the total output ripple, the minimum required ca- pacitance is approximately: I O(MAX) ≥ C OUT 0.01• n • V • f OUT For many designs it will ...
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LTC3862-2 applicaTions inForMaTion The value of the input capacitor is a function of the source impedance, and in general, the higher the source impedance, the higher the required input capacitance. The required amount of input capacitance is also greatly affected ...
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D MAX SLOPE BLANK PHASEMODE 45.3k FREQ 0.1µF SS LTC3862-2 1.5nF 45.3k ITH 100pF FB 5.62k SGND 324k V OUT CLKOUT SYNC PLLFLTR Figure 25a. A 8.5V to 36V Input, 72V/2A Output 2-Phase Boost Converter Application Circuit 2.5 ...
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LTC3862-2 applicaTions inForMaTion The inductor value chosen was 57.8μH and the part number is PA2050-583, manufactured by Pulse Engi- neering. This inductor has a saturation current rating of 5A. 8. The power MOSFET chosen for this application is a Renesas ...
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For the bulk capacitance, which we assume contributes 1% to the total output ripple, the minimum required capacitance is approximately: I O(MAX) C ≥ = OUT 0.01• n • V • f 0.01• 2 • 72V • 300kHz ...
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LTC3862-2 applicaTions inForMaTion 10. The output resistor divider should be located as close as possible to the IC, with the bottom resistor connected between FB and SGND. The PCB trace connecting the top resistor to the upper terminal of the ...
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Typical applicaTions 60V Input, 12V/6A Output 2-Phase SEPIC Application Circuit Q3 PBSS9110T PBZ6.8B 220k 10k R12 56k R27 Q2 22k PMST5550 R13 Q5 10k PMST5550 D MAX SLOPE 3V8 BLANK PHASEMODE R C OSC ...
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LTC3862-2 Typical applicaTions 32V Input, 80V/7A Output 2-Phase Boost Converter Application Circuit D MAX SLOPE BLANK PHASEMODE 110k FREQ 0.1µF SS 10nF LTC3862-2 12k ITH 220pF FB 12.4k SGND 796k V OUT CLKOUT SYNC PLLFLTR Start-Up RUN ...
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Typical applicaTions A 24V Input, 48V/6A Output 2-Phase Boost Converter Application Circuit D MAX SLOPE BLANK PHASEMODE 45.3k FREQ 0.1µF SS 4.7nF LTC3862-2 30.1k ITH 100pF FB 7.87k SGND 301k V OUT CLKOUT SYNC PLLFLTR Start-Up RUN 5V/DIV I L1 ...
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LTC3862-2 Typical applicaTions A 24V Input, 107V/1.5A Output 2-Phase Boost Converter Application Circuit D MAX SLOPE BLANK PHASEMODE 68.1k FREQ 0.1µF SS 2200pF LTC3862-2 43.5k ITH 47pF FB 6.65k SGND 576k V OUT CLKOUT SYNC PLLFLTR L1, L2: CHAMPS TECHNOLOGIES ...
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DescripTion Please refer to http://www.linear.com/designtools/packaging/ 6.60 ±0.10 4.50 ±0.10 SEE NOTE 4 RECOMMENDED SOLDER PAD LAYOUT 4.30 – 4.50* (.169 – .177) 0.09 – 0.20 0.50 – 0.75 (.0035 – .0079) (.020 – .030) NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS ...
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LTC3862-2 package DescripTion Please refer to http://www.linear.com/designtools/packaging/ .254 MIN .0165 ±.0015 RECOMMENDED SOLDER PAD LAYOUT .0075 – .0098 (0.19 – 0.25) .016 – .050 (0.406 – 1.270) NOTE: 1. CONTROLLING DIMENSION: INCHES INCHES 2. DIMENSIONS ARE IN (MILLIMETERS) 3. DRAWING ...
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DescripTion Please refer to http://www.linear.com/designtools/packaging/ 5.40 ±0.05 3.90 ±0.05 3.20 ± 0.05 3.25 REF 3.20 ± 0.05 RECOMMENDED SOLDER PAD LAYOUT APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 5.00 ± 0.10 PIN 1 TOP MARK (NOTE 6) ...
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