LTC3826 Linear Technology, LTC3826 Datasheet
LTC3826
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LTC3826 Summary of contents
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... OPTI-LOOP compensa- tion allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3826 features a precision 0.8V reference and a power good output indicator. A wide 4V to 36V input supply range encompasses all battery chemistries. ...
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... LTC3826IUH#TRPBF LEAD BASED FINISH TAPE AND REEL LTC3826EUH LTC3826EUH#TR LTC3826IUH LTC3826IUH#TR Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi label on the shipping container. For more information on lead free part marking, go to: For more information on tape and reel specifi ...
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... V = 8.5V CC EXTVCC EXTV Ramping Positive Floating; PLLIN/MODE = DC Voltage PLLLPF V = 0V; PLLIN/MODE = DC Voltage PLLLPF V = INTV ; PLLIN/MODE = DC Voltage PLLLPF CC PLLIN/MODE = External Clock; V PLLLPF PLLLPF LTC3826 = 5V unless otherwise noted. MIN TYP MAX l 0.792 0.800 0.808 –5 –50 0.002 0.02 l 0.1 l –0.1 –0.5 0 ...
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... FB V Ramping Positive FB Note 4: The LTC3826 is tested in a feedback loop that servos V specifi ed voltage and measures the resultant V Note 5: Dynamic supply current is higher due to the gate charge being delivered at the switching frequency. See Applications Information. Note 6: Rise and fall times are measured using 10% and 90% levels. Delay times are measured using 50% levels. Note 7: The minimum on-time condition is specifi ...
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... G01 FIGURE 13 CIRCUIT Load Step (Forced Continuous Mode) V OUT 100mV/DIV AC COUPLED I L 2A/DIV 20μs/DIV 3826 G04 FIGURE 13 CIRCUIT V = 3.3V OUT Soft-Start-Up 3826 G07 20ms/DIV FIGURE 13 CIRCUIT LTC3826 Effi ciency vs Input Voltage 12V ...
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... LTC3826 TYPICAL PERFORMANCE CHARACTERISTICS Total Input Supply Current vs Input Voltage www.datasheet4u.com 350 300 250 200 150 300μA LOAD 100 NO LOAD INPUT VOLTAGE (V) Maximum Current Sense Voltage vs I Voltage TH 100 PULSE SKIPPING FORCED CONTINUOUS 80 Burst Mode OPERATION ...
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... INPUT VOLTAGE (V) 3826 G22 Oscillator Frequency vs Input Voltage 392 390 388 386 384 382 380 INPUT VOLTAGE (V) 3826 G25 LTC3826 Regulated Feedback Voltage vs Temperature 808 806 804 802 800 798 796 794 792 –45 –30 – TEMPERATURE (° ...
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... RUN1, RUN2 (Pins 7, 8): Digital Run Control Inputs for Each Controller. Forcing either of these pins below 0.7V shuts down that controller. Forcing both of these pins below 0.7V shuts down the entire LTC3826, reducing quiescent current to approximately 4μA. FOLDDIS (Pin 14): Foldback Current Disable Input Pin. ...
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... TRACK/SS1,2 pin. An internal 1μA pull-up current source is connected to this pin. A capacitor to ground at this pin sets the ramp time to fi nal regulated output voltage. Alternatively, a resistor divider on another voltage supply connected to this pin allows the LTC3826 output to track the other supply during startup (Pins 30, 12): Error Amplifi ...
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... LTC3826 BLOCK DIAGRAM PLLIN/MODE F PHASE DET 5 IN 100k www.datasheet4u.com PHASMD 3 PLLLPF 2 CLK1 R LP OSCILLATOR CLK2 C LP – 0.88V CLKOUT + 4 V FB1 PGOOD1 – 0.72V 0.88V – + PGOOD2 V FB2 28 – + 0.72V – INTV -0. – PLLIN/MODE BURSTEN + 0. 4.7V 5.25V/ – 7.5V EXTV ...
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... CC pin allows the INTV power to be derived from a high CC effi ciency external source such as one of the LTC3826 switching regulator outputs. Each top MOSFET driver is biased from the fl oating boot- strap capacitor C off cycle through an external diode when the top MOSFET turns off ...
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... LTC3826 draws. If one channel is shut down and the other channel is in sleep mode, the LTC3826 draws only 30μA of quiescent current. If both channels are in sleep mode, the LTC3826 draws only 50μA of quiescent current. In sleep mode, the load current is supplied by the output capacitor. As the output voltage decreases, the EA’ ...
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... R-C should be connected between the PLLLPF pin and SGND to serve as the PLL’s loop fi lter. The LTC3826 phase detector adjusts the voltage on the PLLLPF pin to align the turn-on of controller 1’s external top MOSFET to the rising edge of the synchronizing signal. ...
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... EMI and improves real world operating effi ciency. Figure 1 compares the input waveforms for a representa- tive single-phase dual switching regulator to the LTC3826 2-phase dual switching regulator. An actual measure- ment of the RMS input current under these conditions shows that 2-phase operation dropped the input current from 2 ...
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... The schematic on the fi rst page is a basic LTC3826 ap- plication circuit. External component selection is driven ). Figure 2 shows how ...
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... However, lower frequency operation requires more inductance for a given amount of ripple current. The internal oscillator for each of the LTC3826’s controllers runs at a nominal 390kHz frequency when the PLLLPF pin is left fl oating and the PLLIN/MODE pin low or high. ...
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... Power MOSFET and Schottky Diode (Optional) Selection Two external power MOSFETs must be selected for each controller in the LTC3826: one N-channel MOSFET for the top (main) switch, and one N-channel MOSFET for the bottom (synchronous) switch. The peak-to-peak drive levels are set by the INTV This voltage is typically 5V during start-up (see EXTV Connection) ...
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... The sources of the top MOSFETs should be placed within 1cm of each other and share a common C the sources and C current resonances small (0.1μF to 1μF) bypass capacitor between the chip V pin and ground, placed close to the LTC3826, is also sug- gested. A 10Ω resistor placed between C )/( prevent OUT IN pin provides further isolation between the two channels ...
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... The output ripple is highest at maximum input voltage www.datasheet4u.com since I increases with input voltage. RIPPLE Setting Output Voltage The LTC3826 output voltages are each set by an external feedback resistor divider carefully placed across the out- put, as shown in Figure 3. The regulated output voltage is determined by 0.8V • ...
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... MOSFET gate drivers and to prevent interaction between the channels. High input voltage applications in which large MOSFETs 3826 F06b are being driven at high frequencies may cause the maxi- mum junction temperature rating for the LTC3826 to be exceeded. The INTV ...
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... CC Using the EXTV LDO allows the MOSFET driver and CC control power to be derived from one of the LTC3826’s switching regulator outputs (4.7V ≤ V normal operation and from the V is out of regulation (e.g., startup, short-circuit). If more current is required through the EXTV ifi ed, an external Schottky diode can be added between the ...
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... Under short-circuit conditions with very low duty cycles, the LTC3826 will begin cycle skipping in order to limit the short-circuit current. In this situation the bottom MOSFET will be dissipating most of the power but less than in normal operation ...
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... CC RC Loop Filter Minimum On-Time Considerations Minimum on-time t that the LTC3826 is capable of turning on the top MOSFET determined by internal timing delays and the gate charge required to turn on the top MOSFET. Low duty cycle applications may approach this minimum on-time limit and care should be taken to ensure that: ...
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... The output voltage will continue to be regulated, www.datasheet4u.com but the ripple voltage and current will increase. The minimum on-time for the LTC3826 is approximately 230ns. However, as the peak sense voltage decreases the minimum on-time gradually increases up to about 250ns. This is of particular concern in forced continuous applications with low ripple current at light loads ...
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... The gain of the loop will be in- creased by increasing R will be increased by decreasing C the same factor that C will be kept the same, thereby keeping the phase shift the pin not only TH LTC3826 series R -C fi lter sets the dominant pole-zero C C pin waveforms that will ...
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... LTC3826 APPLICATIONS INFORMATION same in the most critical frequency range of the feedback loop. The output voltage settling behavior is related to the stability of the closed-loop system and will demonstrate www.datasheet4u.com the actual overall supply performance. A second, more severe transient is caused by switching in loads with large (>1μF) supply bypass capacitors. The ...
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... EXTV CC SGND C – INTV SENSE2 CC + SENSE2 BG2 BOOST2 V FB2 C B2 SW2 I TH2 TG2 TRACK/SS2 FOLDIS Figure 11. Recommended Printed Circuit Layout Diagram LTC3826 ? Do not attempt to split the input decoupling IN R PU1 V PULL-UP (<8.5V) PGOOD1 L1 R SENSE 1μF CERAMIC C OUT1 VIN ...
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... LTC3826 APPLICATIONS INFORMATION 2. 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 www.datasheet4u.com minals. The path formed by the top N-channel MOSFET, Schottky diode and the C capacitor should have short ...
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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 LTC3826 and occupy minimum PC trace area. 7. Use a modifi ed “star ground” technique: a low imped- ...
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... LTC3826 APPLICATIONS INFORMATION Investigate whether any problems exist only at higher out- put currents or only at higher input voltages. If problems coincide with high input voltages and low output currents, www.datasheet4u.com look for capacitive coupling between the BOOST, SW, TG, and possibly BG connections and the sensitive voltage and current pins ...
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... FOLDDIS MTOP1, MTOP2, MBOT1, MBOT2: Si7848DP L1: CDEP105-2R2M L2: CDEP105-7R2M SANYO 10TPD150M OUT1 OUT2 Start- 3826 F13a Figure 13. High Effi ciency Dual 8.5V/3.3V Step-Down Converter LTC3826 MTOP1 L1 R SNS1 2.2μH 12mΩ C 150μF MBOT1 C C IN1 IN2 10μF 10μF MTOP2 ...
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... OUT 9.5V OUT 0.000001 0.00001 0.0001 0.001 0.01 0.1 1 OUTPUT CURRENT (A) 32 High Effi ciency Dual 5V/9.5V Step-Down Converter LTC3826 I TRACK/SS1 TH1 100k PGOOD2 100k V FB1 PGOOD1 + TG1 SENSE1 – SW1 SENSE1 C 0.47μF B1 BOOST1 PLLLPF PHASMD BG1 CLKOUT ...
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... BG2 B2 0.47μF BOOST2 V FB2 SW2 I TH2 TRACK/SS2 TG2 FOLDDIS 22pF MTOP1, MTOP2, MBOT1, MBOT2: Si7848DP L1: CDEP105-3R2M L2: CDEP105-7R2M SANYO 10TPD150M OUT1 OUT2 LTC3826 MTOP1 L1 R SNS1 3.3μH 12mΩ C OUT1 D3 MBOT1 150μ IN1 IN2 10μF 10μF MTOP2 L2 R SNS2 7.2μ ...
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... C1 1nF C2 1nF R A2 100k C ITH2 R 1nF ITH2 33.2k C ITH2A R B2 100pF 49.9k C SS2 0.01μF 270pF 34 High Effi ciency Dual 1.2V/1V Step-Down Converter LTC3826 I TRACK/SS1 TH1 100k PGOOD2 100k V FB1 PGOOD1 + TG1 SENSE1 – SW1 SENSE1 C 0.47μF B1 BOOST1 PLLLPF PHASMD BG1 CLKOUT D1 V PLLIN/MODE ...
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... Plastic QFN (5mm × 5mm) (Reference LTC DWG # 05-08-1693 Rev D) 0.70 ±0.05 PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC R = 0.05 0.75 ± 0.05 TYP 0.00 – 0.05 3.50 REF (4-SIDES) 0.200 REF LTC3826 BOTTOM VIEW—EXPOSED PAD PIN 1 NOTCH R = 0.30 TYP R = 0.115 OR 0.35 45° CHAMFER TYP 31 32 0.40 ± 0. 3.45 ± 0.10 3.45 ± 0.10 (UH32) QFN 0406 REV D 0.25 ± ...
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... Dual, 550kHz, 2-Phase Synchronous Step-Down Controller trademark of Linear Technology Corporation. SENSE Linear Technology Corporation 36 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● High Effi ciency Dual 3.3V/8V Step-Down Converter LTC3826 I TRACK/SS1 TH1 100k PGOOD2 100k V FB1 PGOOD1 + ...