LTC3728LX Linear Technology, LTC3728LX Datasheet
LTC3728LX
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LTC3728LX Summary of contents
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... MOSFET until V can select among Burst Mode, constant frequency mode and continuous inductor current mode or regulate a secondary winding. The LTC3728L/LTC3728LX include a power good output pin that indicates when both outputs are within 7.5% of their designed set point. , LTC and LT are registered trademarks of Linear Technology Corporation. ...
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... OSENSE1 Peak Output Current <10 s (TG1, TG2, BG1, BG2 INTV Peak Output Current ................................ 40mA CC Operating Temperature Range (Note 7) LTC3728LC/LTC3728LXC ....................... LTC3728LE ........................................ – Junction Temperature (Note 2) ............................ 125 C Storage Temperature Range ................ – 125 C to – 0.3V CC Reflow Peak Body Temperature (UH Package) .... 260 C to – ...
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... Lowest Frequency LOW f Highest Frequency HIGH R PLLIN Input Resistance PLLIN I Phase Detector Output Current PLLFLTR Sinking Capability Sourcing Capability LTC3728L/LTC3728LX The denotes the specifications which apply over the full operating = 15V unless otherwise noted RUN/SS1, 2 CONDITIONS I = 1.2V; (Note 3) TH1, 2 ...
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... Note 6: The minimum on-time condition is specified for an inductor • 34 C/W) peak-to-peak ripple current 40 considerations in the Applications Information section). Note 7: The LTC3728LC/LTC3728LXC are guaranteed to meet to a ITH1, 2 performance specifications from The LTC3728LE is OSENSE1, 2. guaranteed to meet performance specifications over the – operating temperature range as assured by design, characterization and correlation with statistical process controls ...
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... Duty Factor DUTY FACTOR (%) Maximum Current Sense Threshold vs Sense Common Mode Voltage COMMON MODE VOLTAGE (V) LTC3728L/LTC3728LX www.DataSheet4U.com INTV and EXTV Switch CC CC Voltage vs Temperature 5.05 INTV VOLTAGE CC 5.00 4.95 4.90 4.85 4.80 EXTV SWITCHOVER THRESHOLD CC 4.75 4. – 50 – 25 ...
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... LTC3728L/LTC3728LX W U TYPICAL PERFOR A CE CHARACTERISTICS Load Regulation 0.0 FCB = 15V IN FIGURE 13 –0.1 –0.2 –0.3 –0 LOAD CURRENT (A) 3728L G13 Maximum Current Sense Threshold vs Temperature –50 – 100 125 TEMPERATURE ( C) 3728L G17 Soft-Start Up (Figure 13) ...
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... TEMPERATURE ( C) 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0 100 125 –50 3728L G29 LTC3728L/LTC3728LX www.DataSheet4U.com Constant Frequency (Burst Inhibit) Operation (Figure 13) V OUT 20mV/DIV I L 0.5A/DIV V = 15V 2 s/DIV 3728L G23 OUT PLLFLTR FCB I = 20mA OUT Oscillator Frequency ...
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... LTC3728L/LTC3728LX CTIO Error Amplifier Feedback Input. Re- OSENSE1 OSENSE2 ceives the remotely-sensed feedback voltage for each controller from an external resistive divider across the output. PLLFLTR: Filter Connection for Phase-Locked Loop. Al- ternatively, this pin can be driven with voltage source to vary the frequency of the internal oscillator ...
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... I trolled by the voltage on the I each error amplifier EA. The V voltage feedback signal, which is compared to the internal reference voltage by the EA. When the load current in- creases, it causes a slight decrease in V the 0.8V reference, which in turn causes the I LTC3728L/LTC3728LX www.DataSheet4U.com INTV ...
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... LTC3728L/LTC3728LX U OPERATIO (Refer to Functional Diagram) increase until the average inductor current matches the new load current. After the top MOSFET has turned off, the bottom MOSFET is turned on until either the inductor current starts to reverse, as indicated by current compara- tor the beginning of the next cycle. ...
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... The result is a significant reduc- tion in total RMS input current, which in turn allows less expen sive input capacitors to be used, reduces shielding requirements for EMI and improves real world operating efficiency. LTC3728L/LTC3728LX www.DataSheet4U.com 3728lxfa 11 ...
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... LTC3728L/LTC3728LX U OPERATIO (Refer to Functional Diagram 2.53A IN(MEAS) (a) Figure 3. Input Waveforms Comparing Single-Phase (a) and 2-Phase (b) Operation for Dual Switching Regulators Converting 12V to 5V and 3. Each. The Reduced Input Ripple with the LTC1628 2-Phase Regulator Allows Less Expensive Input Capacitors, Reduces Shielding Requirements for EMI and Improves Efficiency ...
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... U U APPLICATIO S I FOR ATIO Figure 1 on the first 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 SENSE and D1 are selected. Finally, C ...
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... However, designs for surface mount are available that do not increase the height significantly. Power MOSFET and D1 Selection Two external power MOSFETs must be selected for each controller in the LTC3728L/LTC3728LX: One N-channel MOSFET for the top (main) switch, and one N-channel MOSFET for the bottom (synchronous) switch. 14 ...
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... The maximum RMS capacitor current is given by This formula has a maximum RMS OUT monly used for design because even significant deviations do not offer much relief. Note that capacitor manufacturer’s LTC3728L/LTC3728LX OUT IN OUT quiredI I RMS ...
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... Always consult the manufacturer if there is any question. The benefit of the LTC3728L/LTC3728LX multiphase clock- ing can be calculated by using the equation above for the higher power controller and then calculating the loss that would have resulted if both controller channels switched on at the same time ...
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... EXTV CC supply is available in the range, it may be used to power EXTV Pin is 40mA. gate drive requirements. CC LTC3728L/LTC3728LX and INTV pins. When CC CC rises above 4.7V, the inter- CC pin to the INTV ...
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... IN(MAX) pins to the main output. The output can be easily preloaded by the V OUT comparator’s negative input bias current. The maximum current flowing out of each pair of SENSE pins is: I SENSE V SEC LTC3728L/ + LTC3728LX SENSE V OUT EXTV OUT 3728 F06a Figure 6b. Capacitive Charge Pump for EXTV ...
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... Soft-Start/Run Function The RUN/SS1 and RUN/SS2 pins are multipurpose pins that provide a soft-start function and a means to shut down the LTC3728L/LTC3728LX. Soft-start reduces the input power source’s surge currents by gradually increas- ing the controller’s current limit (proportional to V This pin can also be used for power supply sequencing. ...
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... LTC3728L/LTC3728LX U U APPLICATIO S I FOR ATIO Diode-connecting this pull-up resistor to INTV Figure 7b, eliminates any extra supply current during controller shutdown while eliminating the INTV from preventing controller start-up. Why should you defeat overcurrent latchoff? During the prototyping stage of a design, there may be a problem with noise pickup or poor layout causing the protection circuit to latch off ...
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... Thus, the is 0. FCB input pin removes the requirement that power must be drawn from the inductor primary in order to extract LTC3728L/LTC3728LX the smallest time duration ON(MIN) V OUT ...
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... ...) where L1, L2, etc. are the individual losses as a percentage of input power. Although all dissipative elements in the circuit produce losses, four main sources usually account for most of the losses in LTC3728L/LTC3728LX circuits (including loading on the 3.3V internal regulator), 2) INTV regulator current transition losses ...
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... ESR values. The availability of the I optimization of control loop behavior but also provides a DC coupled and AC filtered closed loop response test point. The DC step, rise time and settling at this test point LTC3728L/LTC3728LX MAX • ...
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... Note that the transient suppressor should not conduct during double-battery operation, but must still clamp the input voltage below breakdown of the converter. Although the LTC3728L/LTC3728LX have a maximum input voltage of 30V, most applications will also be limited to 30V by the MOSFET BVD . No regulator can OUT www ...
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... ESR of 0.02 for low output ripple. The output ripple in continuous mode will be highest at the maximum input voltage. The output voltage ripple due to ESR is approximately: V ORIPPLE 32 k LTC3728L/LTC3728LX 0.035 /0.022 , C DS(ON 005 50 ( ...
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... I TH2 V OSENSE2 R3 R4 SENSE2 SENSE2 Figure 10. LTC3728L/LTC3728LX Recommended Printed Circuit Layout Diagram Are the signal and power grounds kept separate? The combined IC signal ground pin and the ground return of C must return to the combined C INTVCC The path formed by the top N-channel MOSFET, Schottky diode and the C PC trace lengths. The output capacitor (– ...
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... All of these nodes have very large and fast moving signals and therefore should be kept on the “output side” of the LTC3728L/LTC3728LX and occupy minimum PC trace area. LTC3728L/LTC3728LX www.DataSheet4U.com ...
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... LTC3728L/LTC3728LX U U APPLICATIO S I FOR ATIO 7. Use a modified “star ground” technique: a low imped- ance, large copper area central grounding point on the same side of the PC board as the input and output capacitors with tie-ins for the bottom of the INTV decoupling capacitor, the bottom of the voltage feedback resistive divider and the SGND pin of the IC ...
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... 28V 5V, 3A/3.3V, 6A/12V, 150mA OUT SWITCHING FREQUENCY = 250kHz MI, M2: FDS6982S OR VISHAY Si4810DY L1: SUMIDA CEP123-6R3MC T1 1:1.8 — DALE LPE6562-A262 GAPPED E-CORE OR BH ELECTRONICS #501-0657 GAPPED TOROID Figure 12. LTC3728L/LTC3728LX High Efficiency Low Noise 5V/3A, 3.3V/5A, 12V/120mA Regulator 1M 100k MBRS1100T3 V PULL-UP (<7V) PGOOD PGOOD TG1 M1 ...
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... 28V SWITCHING FREQUENCY = 250kHz TO 550kHz 5V, 4A/3.3V, 5A M1, M2: FDS6982S OR VISHAY Si4810DY OUT Figure 13. LTC3728L/LTC3728LX 5V/4A, 3.3V/5A Regulator with External Frequency Synchronization 30 V PULL-UP (<7V) RUN/SS1 PGOOD PGOOD + SENSE1 TG1 – SENSE1 SW1 0 BOOST1 OSENSE1 PLLFLTR ...
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... M0-220 VARIATION WHHD-(X) (TO BE APPROVED) 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.20mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED LTC3728L/LTC3728LX www.DataSheet4U.com .386 – .393* .033 (9.804 – 9.982) (0.838) ...
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... TYPICAL APPLICATIO 0 OPEN PHASMD TG1 180 TG2 U1 LTC3729 90 CLKOUT 90 TG1 270 U2 TG2 LTC3728L/ LTC3728LX 90 PLLIN RELATED PARTS PART NUMBER DESCRIPTION LTC1628/LTC1628-PG/ 2-Phase, Dual Output Synchronous Step-Down LTC1628-SYNC DC/DC Controller LTC1629/ 20A to 200A PolyPhase LTC1629-PG LTC1702A No R 2-Phase Dual Synchronous Step-Down SENSE Controller ...