LTC1439 Linear Technology, LTC1439 Datasheet
LTC1439
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LTC1439 Summary of contents
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... PGND RUN/SS2 DSC PROG2 SS1 OSC 10k 0.1 F 56pF 0.1 F *NOT REQUIRED FOR LTC1438 BOLD LINES INDICATE HIGH CURRENT PATHS LTC1438/LTC1439 Dual High Efficiency, U ® 1438/LTC1439 are dual, synchronous step 5.2V TO 28V 4 16V 35V M6 0 ...
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... AUXDR G PACKAGE 36-LEAD PLASTIC SSOP T = 125 C, JMAX T = 125 C, JMAX TOP VIEW ORDER PART NUMBER 36 PLL LPF PLLIN 35 34 BOOST 1 LTC1439CG 33 TGL1 LTC1439IG 32 SW1 LTC1439CGW 31 TGS1 LTC1439IGW BG1 28 INTV CC 27 PGND 26 BG2 EXTV TGS2 23 SW2 22 TGL2 21 BOOST 2 AUXON 20 19 ...
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... V < 30V EXTVCC I = 20mA INTVCC EXTVCC I = 20mA INTVCC EXTVCC I = 20mA, EXTV Ramping Positive INTVCC 100pF, LTC1439: PLL LPF = 0V (Note 4) OSC LTC1439 2.4V PLLLPF LTC1439 f < f PLLIN OSC f > f PLLIN OSC I = 1.6mA 1V, POR2 OSENSE2 V Pin Open PROG2 ...
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... D LTC1438CG, LTC1439CG )(95 C/ LTC1439CGW )(85 C/ Note 2: The LTC1438 and LTC1439 are tested in a feedback loop which servos V to the balance point for the error amplifier OSENSE1 1.19V). ITH1 15V RUN/SS1,2 CONDITIONS ...
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... CC vs INTV Load Current EXTV = – – INTV LOAD CURRENT (mA) CC LTC1438/LTC1439 Efficiency vs Load Current 100 V = 10V OUT R = 0.33 SENSE 90 CONTINUOUS 85 MODE 80 Burst Mode 75 OPERATION 70 65 Adaptive Power 60 MODE 55 50 ...
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... LTC1438/LTC1439 W U TYPICAL PERFORMANCE CHARACTERISTICS Normalized Oscillator Frequency vs Temperature – 5 –10 – 40 – 110 135 TEMPERATURE ( C) 1438 G10 Maximum Current Sense Threshold Voltage vs Temperature 154 152 150 148 146 – 40 – 110 135 TEMPERATURE ( C) 1438 G13 ...
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... V sensing point. The first controller can only be used as a 3.3V or 5.0V regulator controlled by the V bypassing the internal the LTC1438, LTC1438X and LTC1439. The LTC1438-ADJ is higher than Controller 1 implements a remote sensing adjustable CC regulator. The second controller can be set to a 3.3V, 5. adjustable regulator controlled by the V (see Table 1) ...
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... LTC1438/LTC1439 PIN FUNCTIONS + + SENSE 1, SENSE 2: The (+) Input to Each Current Comparator. Built-in offsets between SENSE + SENSE 1 pins in conjunction with R trip threshold (same for second controller Receives the remotely sensed feedback volt- OSENSE1,2 age either from the output directly or from an external resistive divider across the output. The V mines which point V must connect to ...
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... EA – REF 1.19V REF + 0V – 1.28V 5V LDO 3 A 1.19V SHUTDOWN RUN SOFT START 6V SUPPLY † **NOT AVAILABLE ON LTC1438 FOLDBACK CURRENT LIMITING OPTION LTC1438/LTC1439 V IN BOOST TGL SFB TGS** SWITCH LOGIC SW INTV CC BG PGND INTV CC – – SENSE + SENSE 4k V ...
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... MOSFET and keeping it off until the fault is removed. 10 Low Current Operation Adaptive Power mode allows the LTC1439 to automati- cally change between two output stages sized for different load currents. The TGL1 (TGL2) and BG1 (BG2) pins drive large synchronous N-channel MOSFETs for operation at ...
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... U OPERATION (Refer to Functional Diagram) Frequency Synchronization A Phase-Locked Loop (PLL) is available on the LTC1439 to allow the oscillator to be synchronized to an external source connected to the PLLIN pin. The output of the phase detector at the PLL LPF pin is also the control input of the oscillator, which operates over 2.4V range corresponding to – ...
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... LTC1438/LTC1439 U U APPLICATIONS INFORMATION The basic LTC1439 application circuit is shown in Fig- ure 1. External component selection is driven by the load requirement and begins with the selection known, C and L can be chosen. Next, the SENSE OSC power MOSFETs and D1 are selected. Finally, C are selected. The circuit shown in Figure 1 can be config- ured for operation input voltage of 28V (limited by the external MOSFETs) ...
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... OUT V = 3.3V OUT V = 2.5V controller with the LTC1439: a pair of N-channel MOSFETs OUT for the top (main) switch and an N-channel MOSFET for the bottom (synchronous) switch. Only one top MOSFET is required for each LTC1438 controller. To take advantage of the Adaptive Power output stage, two topside MOSFETs must be selected. A large [low R MOSFET and a small [higher R quired ...
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... The peak-to-peak drive levels are set by the INTV age. This voltage is typically 5V during start-up (see EXTV Pin Connection). Consequently, logic level thresh- CC old MOSFETs must be used in most LTC1438/LTC1439 applications. The only exception is applications in which EXTV is powered from an external supply greater than CC ...
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... W U High input voltage applications in which large MOSFETs are being driven at high frequencies may cause the maxi- mum junction temperature rating for the LTC1438/LTC1439 to be exceeded. The IC supply current is dominated by the gate charge supply current when not using an output derived EXTV operating frequency as discussed in the Efficiency Consid- erations section ...
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... V SEC be greater than 1:1 Output Voltage Programming R SENSE V OUT • The LTC1438/LTC1439 have pin selectable output voltage + programming. Controller 1 on the LTC1438-ADJ OUT dedicated adjustable controller. The output voltage is 1438 F04a selected by the V other parts: V PROG1,2 Connection CC V PROG1,2 ...
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... F, followed by a similar time reach full current on that controller. By pulling both RUN/SS controller pins below 1.3V, the LTC1438/LTC1439 are put into low current shutdown (I < 25 A). These pins can be driven directly from logic Q as shown in Figure 6. Diode D1 in Figure 6 reduces the start delay but allows C start function ...
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... This technique may be used for all applica- tions with regulated output voltages of 1.8V or greater. Phase-Locked Loop and Frequency Synchronization The LTC1439 has an internal voltage-controlled oscillator and phase detector comprising a phase-locked loop. This allows the top MOSFET turn- locked to the rising edge of an external source ...
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... U U APPLICATIONS INFORMATION C holds the voltage. The LTC1439 PLLIN pin must be LP driven from a low impedance such as a logic gate located close to the pin. Any external attenuator used needs to be referenced to SGND. The loop filter components current pulses from the phase detector and provide a stable input to the voltage-controlled oscillator ...
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... SEC AUXDR R6 V OAUX SFB1 AUXFB 12V + R5 LTC1439 10 F AUXON ON/OFF 1438 F11a 1.19V 1 + > V SEC OAUX R5 AUXDR R6 R8 SFB1 AUXFB + LTC1439 AUXON ON/OFF 1438 F11b V 7.5V PULL-UP LTC1439 AUXON AUXDR OUTPUT AUXFB – + 1.19V REFERENCE 1438 F11c V OAUX ...
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... Efficiency = 100% – ( ...) 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 LTC1438/LTC1439 circuits. LTC1438/LTC1439 2 V current, INTV current losses and topside MOSFET ...
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... With the 0.033 sense resistor I increasing the Si4412DY dissipation to 950mW at a die temperature of 105 C. LTC1438 C will require an RMS current rating of at least 1.5A at LTC1439 IN temperature and C output ripple. The output ripple in continuous mode will be highest at the maximum input voltage. The output voltage 1438 F12 ...
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... PC Board Layout Checklist When laying out the printed circuit board, the following checklist should be used to ensure proper operation of the LTC1438/LTC1439. These items are also illustrated graphi- cally in the layout diagram of Figure 13. Check the follow- ing in your layout: 1. Are the high current power ground current paths using ...
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... PC trace spacing? The filter capacitors be tween SENSE 1 (SENSE 2) and SENSE should be as close as possible to the LTC1438/LTC1439 the (+) plates of C connect to the drains of the IN topside MOSFETs as closely as possible? This capacitor provides the AC current to the MOSFETs the INTV ...
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... EXTV CC OUT1 SW2 TH2 TGL2 OSENSE2 13 16 – SENSE 2 BOOST 0.1 F SENSE 2 RUN/SS2 LTC1438/LTC1439 ground and the ground from the 35V 35V 10 H SUMIDA M1 CDRH125-100MC 0.033 + 220 F MBRS140T3 M2 10V 220 F M4 10V MBRS140T3 + 0.033 ...
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... LTC1438/LTC1439 U TYPICAL APPLICATIONS LTC1439 High Efficiency Low Noise 5V/3A, 3.3V/3.5A and 12V/200mA Regulator 0. 10k C SS1 0 RUN/SS1 1000pF 2 SENSE C 1000pF 3 C1A SENSE 220pF INTV V 1000pF CC PROG1 5 I TH1 R POR2 6 C1 POR2 10k C OSC 100k 56pF 7 C OSC 8 SGND 110k LBI ...
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... U TYPICAL APPLICATIONS LTC1438/LTC1439 27 ...
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... LTC1438/LTC1439 U TYPICAL APPLICATIONS 28 ...
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... U PCB LAYOUT A D FIL Silkscreen Top Copper Layer 1 Copper Layer 3 W (Gerber files for this circuit board are available. Call LTC Marketing.) LTC1438/LTC1439 Silkscreen Bottom Copper Layer 2 Ground Plane Copper Layer 4 29 ...
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... LTC1438/LTC1439 PACKAGE DESCRIPTION 0.205 – 0.212** (5.20 – 5.38) 0.022 – 0.037 0.005 – 0.009 (0.13 – 0.22) (0.55 – 0.95) * DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 0.205 – ...
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... TYP 0.031 (0.800) TYP ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE LTC1438/LTC1439 0.602 – 0.612* (15.290 – 15.544) 0.400 – 0.410 (10.160 – 10.414) 0.090 – 0.094 (2.286 – 2.387) 0.005 – 0.012 0.012 – ...
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... Linear Technology Corporation 32 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 : (408) 434-0507 FAX TELEX 3. Low Noise Linear Regulator 5V 27 6.8nF 47k Q1 MMBT2907ALTI 10 100 AUXDR 316k LTC1439 22pF 1% AUXFB 221k 1% : 499-3977 3.3V ZETEX FZT849 (SURFACE MOUNT) 2. 330 F 2 1438 TA05 COMMENTS Dual Synchronous, V ...