LTC3728LXCUH#TR Linear Technology, LTC3728LXCUH#TR Datasheet
LTC3728LXCUH#TR
Specifications of LTC3728LXCUH#TR
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LTC3728LXCUH#TR Summary of contents
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... L, LT, LTC, LTM, Linear Technology, the Linear logo, Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. ...
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LTC3728L/LTC3728LX ABSOLUTE MAXIMUM RATINGS Input Supply Voltage (V ) ........................ 30V to – 0.3V IN Topside Driver Voltages (BOOST1, BOOST2) .............................. 36V to –0.3V Switch Voltage (SW1, SW2) ........................ 30V to –5V INTV EXTV , RUN/SS1, RUN/SS2, CC, CC (BOOST1-SW1), ...
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... LTC3728LCUH#TR LTC3728LEUH LTC3728LEUH#TR LTC3728LIUH LTC3728LIUH#TR LTC3728LXCUH LTC3728LXCUH#TR Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. For more information on lead free part marking, go to: For more information on tape and reel specifi cations, go to: LTC3728L/LTC3728LX PART MARKING PACKAGE DESCRIPTION ...
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LTC3728L/LTC3728LX ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T SYMBOL PARAMETER Main Control Loops V Regulated Feedback Voltage OSENSE1 Feedback Current VOSENSE1 Reference Voltage Line Regulation REFLNREG V Output Voltage Load Regulation LOADREG g ...
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ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T SYMBOL PARAMETER INTV Linear Regulator CC V Internal V Voltage INTVCC CC V INT INTV Load Regulation LDO CC V EXT EXTV Voltage Drop LDO CC V EXTV Switchover Voltage ...
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LTC3728L/LTC3728LX TYPICAL PERFORMANCE CHARACTERISTICS Effi ciency vs Output Current and Mode (Figure 13) 100 Burst Mode 90 OPERATION 80 70 FORCED 60 CONTINUOUS MODE (PWM CONSTANT FREQUENCY 30 (BURST DISABLE 15V ...
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TYPICAL PERFORMANCE CHARACTERISTICS Maximum Current Sense Threshold vs V (Soft-Start) RUN/ 1.6V SENSE(CM (V) RUN/SS 3728L G10 Load Regulation 0.0 FCB = 15V ...
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LTC3728L/LTC3728LX TYPICAL PERFORMANCE CHARACTERISTICS Soft-Start Up (Figure 13) V OUT 5V/DIV V RUN/SS 5V/DIV I L 2A/DIV 3728L G19 V = 15V 5ms/DIV OUT Input Source/Capacitor Instantaneous Current (Figure 13 2A/DIV V IN 200mV/DIV ...
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TYPICAL PERFORMANCE CHARACTERISTICS Current Sense Pin Input Current vs Temperature OUT –50 –25 100 TEMPERATURE (°C) 3728L G26 Undervoltage Lockout vs Temperature 3.50 3.45 3.40 3.35 3.30 ...
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LTC3728L/LTC3728LX PIN FUNCTIONS Error Amplifi er Feedback Input. OSENSE1 OSENSE2 Receives the remotely sensed feedback voltage for each controller from an external resistive divider across the output. PLLFLTR: Filter Connection for Phase-Locked Loop. Alter- natively, this ...
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FUNCTIONAL DIAGRAM PLLIN F PHASE DET IN 50k PLLFLTR CLK1 R LP OSCILLATOR CLK2 C LP – 0.86V + V OSENSE1 PGOOD – + 0.74V 0.86V – OSENSE2 – + 0.74V INTV CC 3V – 4.5V 0.18μA BINH ...
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LTC3728L/LTC3728LX OPERATION (Refer to Functional Diagram) Main Control Loop The IC uses a constant-frequency, current mode step-down architecture with the two controller channels operating 180 degrees out of phase. During normal operation, each top MOSFET is turned on when the ...
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OPERATION (Refer to Functional Diagram) Constant-Frequency Operation When the FCB pin is tied to INTV CC tion is disabled and the forced minimum output current requirement is removed. This provides constant-frequency, discontinuous current (preventing reverse inductor cur- rent) operation over ...
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LTC3728L/LTC3728LX OPERATION (Refer to Functional Diagram) THEORY AND BENEFITS OF 2-PHASE OPERATION The LTC1628 and the LTC3728L family of dual high effi - ciency DC/DC controllers brings the considerable benefi 2-phase operation to portable applications for the fi ...
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OPERATION (Refer to Functional Diagram) duty cycles which, in turn, are dependent upon the input voltage V (Duty Cycle = Figure 4 shows how IN OUT IN the RMS input current varies for single-phase and 2-phase operation ...
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LTC3728L/LTC3728LX APPLICATIONS INFORMATION Figure 1 on the fi rst page is a basic LTC3728L/LTC3728LX application circuit. External component selection is driven by the load requirement, and begins with the selection of R and the inductor value. Next, the power MOSFETs ...
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APPLICATIONS INFORMATION The inductor value also has secondary effects. The tran- sition to Burst Mode operation begins when the average inductor current required results in a peak current below 25% of the current limit determined by R inductor values (higher ...
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LTC3728L/LTC3728LX APPLICATIONS INFORMATION where δ is the temperature dependency (approximately 4Ω) is the effective driver resistance DR at the MOSFET’s Miller threshold voltage. V typical MOSFET minimum threshold voltage. 2 Both MOSFETs have I R losses while ...
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APPLICATIONS INFORMATION current ratings are often based on only 2000 hours of life. This makes it advisable to further derate the capacitor choose a capacitor rated at a higher temperature than required. Several capacitors may also be paralleled ...
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LTC3728L/LTC3728LX APPLICATIONS INFORMATION Panasonic SP , NEC Neocap, Cornell Dubilier ESRE and Sprague 595D series. Consult manufacturers for other specifi c recommendations. INTV Regulator CC An internal P-channel low dropout regulator produces 5V at the INTV pin from the V ...
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APPLICATIONS INFORMATION 4. EXTV Connected to an Output-Derived Boost Network. CC For 3.3V and other low voltage regulators, effi ciency gains can still be realized by connecting EXTV output-derived voltage that has been boosted to greater than 4.7V. This can ...
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LTC3728L/LTC3728LX APPLICATIONS INFORMATION Since V is servoed to the 0.8V reference voltage, OSENSE we can choose R1 in Figure 2 to have a maximum value to absorb this current. 0.8V = 24k R1 (MAX) 2.4V – V OUT for V ...
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APPLICATIONS INFORMATION with noise pickup or poor layout causing the protection circuit to latch off. Defeating this feature will easily allow troubleshooting of the circuit and PC layout. The internal short-circuit and foldback current limiting still remains active, thereby protecting ...
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LTC3728L/LTC3728LX APPLICATIONS INFORMATION The output of the phase detector is a complementary pair of current sources charging or discharging the external fi lter network on the PLLFLTR pin. If the external frequency ( greater than the os- PLLIN ...
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APPLICATIONS INFORMATION If V drops below this level, the FCB voltage forces SEC temporary continuous switching operation until V again above its minimum. In order to prevent erratic operation if no external connec- tions are made to the FCB pin, ...
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LTC3728L/LTC3728LX APPLICATIONS INFORMATION Supplying INTV power through the EXTV CC input from an output-derived source will scale the V current required for the driver and control circuits by a factor of (Duty Cycle)/(Effi ciency). For example 20V to ...
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APPLICATIONS INFORMATION of full-load current having a rise time of 1μs to 10μs will produce output voltage and I pin waveforms that will TH give a sense of the overall loop stability without break- ing the feedback loop. Placing a ...
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LTC3728L/LTC3728LX APPLICATIONS INFORMATION Design Example As a design example for one channel, assume V (nominal 22V(max 1.8V OUT f = 300kHz. The inductance value is chosen fi rst based on a 30% ripple current ...
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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 10. Figure ...
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LTC3728L/LTC3728LX APPLICATIONS INFORMATION BOLD LINES INDICATE HIGH SWITCHING CURRENT. KEEP LINES TO A MINIMUM LENGTH. – Are the SENSE and SENSE leads routed together with minimum PC trace spacing? The fi ...
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APPLICATIONS INFORMATION PC Board Layout Debugging Start with one controller time helpful to use a DC-50MHz current probe to monitor the current in the inductor while testing the circuit. Monitor the output switching node (SW ...
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LTC3728L/LTC3728LX TYPICAL APPLICATIONS 59k RUN/SS1 0.1μF + SENSE1 180pF 1000pF – SENSE1 105k, 1% 20k 1% V OSENSE1 PLLFLTR PLLIN 33pF FCB LTC3728L/LTC3728LX I TH1 15k 1000pF SGND 33pF 3.3V 3.3V OUT I TH2 15k 1000pF V OSENSE2 20k 1% ...
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TYPICAL APPLICATIONS 0.1μF 180pF 1000pF 105k 1% 20k 1% 0.01μF 10k 1000pF f SYNC 100pF 8.06k 1500pF 100pF 3.3V 4.75k 1000pF 20k 1% 63.4k 1000pF 1% 180pF 0.1μ 28V SWITCHING FREQUENCY = 250kHz TO 550kHz IN ...
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LTC3728L/LTC3728LX PACKAGE DESCRIPTION .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 NOT TO SCALE ...
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... ON THE TOP AND BOTTOM OF PACKAGE 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. LTC3728L/LTC3728LX UH Package 32-Lead Plastic QFN (5mm × ...
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... Dual, 550kHz, 2-Phase Synchronous Step-Down Controller Dual 180° Phased Controllers, V LTC3729 20A to 200A, 550kHz PolyPhase Synchronous Controller LTC3731 3- to 12-Phase Step-Down Synchronous Controller PolyPhase is a registered trademark of Linear Technology Corporation Linear Technology Corporation 36 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● ...