LTC3835EDHC-1#TRPBF Linear Technology, LTC3835EDHC-1#TRPBF Datasheet
LTC3835EDHC-1#TRPBF
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LTC3835EDHC-1#TRPBF Summary of contents
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FEATURES n Wide Output Voltage Range: 0.8V ≤ Low Operating I : 80μA Q ® n OPTI-LOOP Compensation Minimizes C n ±1% Output Voltage Accuracy n Wide V Range 36V Operation IN n Phase-Lockable Fixed Frequency ...
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... PLASTIC DFN = 125°C, θ 43.5°C/W JMAX JA EXPOSED PAD (PIN 17) IS SGND MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL LTC3835EDHC-1#PBF LTC3835EDHC-1#TRPBF LTC3835IDHC-1#PBF LTC3835IDHC-1#TRPBF LTC3835EGN-1#PBF LTC3835EGN-1#TRPBF LTC3835IGN-1#PBF LTC3835IGN-1#TRPBF LEAD BASED FINISH TAPE AND REEL LTC3835EDHC-1 LTC3835EDHC-1#TR LTC3835IDHC-1 ...
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ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T SYMBOL PARAMETER Main Control Loop V Regulated Feedback Voltage FB I Feedback Current VFB V Reference Voltage Line Regulation REFLNREG V Output Voltage Load Regulation LOADREG g Transconductance Amplifi er ...
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... T J dissipation P according to the following formulas: D LTC3835GN- • 90°C/ LTC3835EDHC- • 43.5°C/ Note 4: The LTC3835-1 is tested in a feedback loop that servos V specifi ed voltage and measures the resultant V TYPICAL PERFORMANCE CHARACTERISTICS Effi ciency and Power Loss vs Output Current ...
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TYPICAL PERFORMANCE CHARACTERISTICS Inductor Current at Light Load FORCED CONTIN- UOUS MODE 2A/DIV Burst Mode OPERATION PULSE- SKIPPING MODE 38351 G07 4μs/DIV FIGURE 10 CIRCUIT V = 3.3V OUT I = 300μA LOAD Total Input Supply Current vs Input Voltage ...
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LTC3835-1 TYPICAL PERFORMANCE CHARACTERISTICS Foldback Current Limit 120 TRACK/ 100 0.6 0.7 0.8 0 0.1 0.2 0.3 0.4 0.5 FEEDBACK VOLTAGE (V) 38351 G16 TRACK/SS Pull-Up Current vs Temperature 1.20 1.15 1.10 1.05 ...
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TYPICAL PERFORMANCE CHARACTERISTICS Undervoltage Lockout Threshold vs Temperature 4.2 4.1 4.0 3.9 RISING 3.8 3.7 3.6 3.5 FALLING 3.4 3.3 3.2 –45 –30 – TEMPERATURE (°C) 38351 G25 PIN FUNCTIONS (DHC Package/GN Package) PLLLPF ...
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LTC3835-1 PIN FUNCTIONS (DHC Package/GN Package) RUN (Pin 13/Pin 13): Digital Run Control Input for Controller. Forcing this pin below 0.7V shuts down all controller functions, reducing the quiescent current that the LTC3835-1 draws to approximately 10μA. – SENSE (Pin ...
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OPERATION (Refer to Functional Diagram) Main Control Loop The LTC3835-1 uses a constant-frequency, current mode step-down architecture. During normal operation, each external top MOSFET is turned on when the clock sets the RS latch, and is turned off when the ...
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LTC3835-1 OPERATION (Refer to Functional Diagram) Light Load Current Operation (Burst Mode Operation, Pulse-Skipping, or Continuous Conduction) (PLLIN/MODE Pin) The LTC3835-1 can be enabled to enter high effi ciency Burst Mode operation, constant-frequency pulse-skipping mode, or forced continuous conduction mode ...
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OPERATION (Refer to Functional Diagram) The typical capture range of the LTC3835-1’s phase- locked loop is from approximately 115kHz to 800kHz, with a guarantee to be between 140kHz and 650kHz. In other words, the LTC3835-1’s PLL is guaranteed to lock ...
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LTC3835-1 APPLICATIONS INFORMATION Accepting larger values of ΔI allows the use of low L inductances, but results in higher output voltage ripple and greater core losses. A reasonable starting point for setting ripple current is ΔI = 0.3(I L ΔI ...
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APPLICATIONS INFORMATION The MOSFET power dissipations at maximum output current are given by OUT 1 δ MAIN MAX ⎛ ⎞ ...
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LTC3835-1 APPLICATIONS INFORMATION Setting Output Voltage The LTC3835-1 output voltage is set by an external feed- back resistor divider carefully placed across the output, as shown in Figure 1. The regulated output voltage is determined by: ⎛ ⎞ ...
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APPLICATIONS INFORMATION Alternatively, the TRACK/SS pin can be used to track two (or more) supplies during start-up, as shown qualitatively in Figures 4a and 4b this, a resistor divider should be connected from the master supply (V SS ...
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LTC3835-1 APPLICATIONS INFORMATION High input voltage applications in which large MOSFETs are being driven at high frequencies may cause the maximum junction temperature rating for the LTC3835 exceeded. The INTV current, which is dominated CC by the gate ...
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APPLICATIONS INFORMATION Phase-Locked Loop and Frequency Synchronization The LTC3835-1 has a phase-locked loop (PLL) comprised of an internal voltage-controlled oscillator (VCO) and a phase detector. This allows the turn-on of the top MOSFET to be locked to the rising edge ...
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LTC3835-1 APPLICATIONS INFORMATION If the external clock frequency is greater than the internal oscillator’s frequency then current is sourced con- OSC tinuously from the phase detector output, pulling up the PLLLPF pin. When the external clock frequency is ...
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APPLICATIONS INFORMATION Effi ciency Considerations The percent effi ciency of a switching regulator is equal to the output power divided by the input power times 100 often useful to analyze individual losses to determine what is limiting the ...
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LTC3835-1 APPLICATIONS INFORMATION Checking Transient Response The regulator loop response can be checked by looking at the load current transient response. Switching regulators take several cycles to respond to a step in DC (resistive) load current. When a load step ...
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APPLICATIONS INFORMATION Design Example As a design example, assume V = 12V(nominal 22V(max 1.8V and f = 250kHz. OUT MAX The inductance value is chosen fi rst based on a 30% ripple current ...
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LTC3835-1 APPLICATIONS INFORMATION PC Board Layout Checklist When laying out the printed circuit board, the following checklist should be used to ensure proper operation of the IC. These items are also illustrated graphically in the layout diagram of Figure 8. ...
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APPLICATIONS INFORMATION BOLD LINES INDICATE HIGH SWITCHING CURRENT. KEEP LINES TO A MINIMUM LENGTH. PC Board Layout Debugging It is helpful to use a DC-50MHz current probe to monitor the current in the inductor ...
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LTC3835-1 TYPICAL APPLICATIONS 0.01μF 560pF 100pF 35k 39.2k 432k 0.01μF 330pF 100pF 33k 20k 62.5k M1, M2: Si4840DY L1 TOKO 053LC A915AY-3R3M 24 High Effi ciency 9.5V, 3A Step-Down Converter PLLLPF RUN C B 0.22μF TRACK/SS BOOST ...
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TYPICAL APPLICATIONS 0.01μF 470pF 10k 69.8k 365k GND 0.01μF 2.2nF 10k 118k 59.5k High Effi ciency 5V, 5A Step-Down Converter PLLLPF RUN C B 0.22μF TRACK/SS BOOST LTC3835-1 100pF SGND INTV CC 4.7μF PLLIN/MODE ...
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LTC3835-1 PACKAGE DESCRIPTION 3.50 ±0.05 1.65 ±0.05 2.20 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS PIN 1 TOP MARK (SEE NOTE 6) 0.200 REF NOTE: 1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WJED-1) IN JEDEC PACKAGE ...
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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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. ...
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... PolyPhase Synchronous Controller LTC3731 3- to 12-Phase Step-Down Synchronous Controller LTC3827/ Low I Dual Synchronous Controllers Q LTC3827 trademark of Linear Technology Corporation. PolyPhase is a registered trademark of Linear Technology Corporation. SENSE Linear Technology Corporation 28 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● PLLLPF ...