LTC3425 Linear Technology, LTC3425 Datasheet
LTC3425
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LTC3425 Summary of contents
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... The LTC3425 is available in a small, thermally enhanced 32-pin QFN package. , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. ...
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... GNDB 7 GNDB 8 T JMAX EXPOSED PAD IS GND (PIN 33) MUST BE SOLDERED TO PCB ORDER PART NUMBER LTC3425EUH Consult LTC Marketing for parts specified with wider operating temperature ranges. The denotes the specifications which apply over the full operating = 1.2V 3.3V OUT CONDITIONS ...
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... PGOOD Falling Edge Note 5: The LTC3425E is guaranteed to meet performance specifications from Specifications over the – operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 6: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction IN temperature will exceed 125 C when overtemperature protection is active ...
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... LTC3425 W U TYPICAL PERFOR A CE CHARACTERISTICS SWA, SWB, SWC, SWD at 1MHz/Phase SWA TO SWD 5V/DIV 250ns/DIV Transient Response 0.5A to 1.5A Fixed Frequency Mode Operation V AC OUT 100mV/DIV LOAD CURRENT 0.5A/DIV V = 2.4V 100 s/DIV 3.3V OUT C = 220 F OUT Soft-Start and Inrush Current Limiting I IN 0.5A/DIV SS Pin ...
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... LOAD (mA) 3425 G15 Peak Current Limit 1 1.6 1.4 1.2 1.0 0.8 0 100 120 140 160 180 200 I RESISTOR (k ) LIM 3425 G18 LTC3425 www.DataSheet4U.com Converter Efficiency for 2-, 3- and 4-Phase Operation 2. 3.3V OUT 94 1MHz/PHASE PHASE PHASE 3 PHASE 84 82 ...
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... LTC3425 W U TYPICAL PERFOR A CE CHARACTERISTICS Maximum Output Current in Burst Mode Operation 350 300 V = 3.3V OUT 250 OUT 200 150 100 1.5 2 2.5 3 3.5 4 4.5 V (V) IN 3425 G20 Automatic Burst Mode Thresholds 100 OUT 3.3V OUT 80 LEAVE Burst Mode OPERATION ...
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... TEMPERATURE ( C) Quiescent 115 –45 3425 G32 LTC3425 www.DataSheet4U.com Oscillator Frequency vs Temperature 2.0 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 95 115 –45 –25 – TEMPERATURE ( C) 3425 G30 Error Amplifier Temperature –25 –5 ...
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... LTC3425 CTIO S GNDA–D (Pins 17, 18, 23, 24): Power Ground for the IC and the Four Internal N-channel MOSFETs. Connect directly to the power ground plane. SWA–D (Pins 3, 6, 19, 22): Switch Pins. Connect induc- tors here. Minimize trace length to keep EMI to a mini- mum ...
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... SS. The actual rise time of V function of load and output capacitance. Exposed Pad (Pin 33): Additional Power Ground for the IC. Connect directly to the power ground plane. BURST PIN RC Network to Ground Low High High LTC3425 www.DataSheet4U.com ( F) • 320 SS OUT CCM PIN Low Low Low ...
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... LTC3425 W BLOCK DIAGRA PMOS – 0.8V ENABLE MODE CONTROL CCM 26 DIVIDER 4-PHASE GEN 4 CLK 4 R IOSC T 28 OSC SYNCIN 30 SYNC SYNCOUT 25 THERMAL SHDN SHDN SHUTDOWN OFF REF REFEN OFF ON REFOUT 9 + REFOUT 15 – GNDA GNDB 4. ...
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... This is illustrated in the waveforms of Figures 2 and 3. Operation Using Only Two or Three Phases The LTC3425 can operate 3-phase converter by simply eliminating the inductor from the unused phase(s). LTC3425 www.DataSheet4U.com ...
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... This approach can be used to reduce solution cost and board area in applications not requiring the full power capability of the LTC3425, or where peak efficiency may not be as important as cost and size. In this case, phase A should always be used, since this is the only phase active ...
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... The limiting factor for the application becomes the ability of the power source to supply sufficient energy to the output at the low volt- ages, and the maximum duty cycle that is clamped at 90%. LTC3425 www.DataSheet4U.com 3432 F03 OUT input voltage, eliminating the requirement for a ...
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... LOAD (mA) Figure 4. LTC3425 Efficiency vs Load for 2-, 3- and 4-Phase Operation Low Noise Fixed Frequency Operation Shutdown: The part is shut down by pulling SHDN below 0.25V and made active by pulling the pin above 1V. Note that SHDN can be driven above limited to less than 5 ...
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... Burst Mode operation. To minimize the effects of leakage current and stray resistance, voltage clamps limit the min and max voltage on COMP during Burst Mode operation. This minimizes the transient experienced when LTC3425 www.DataSheet4U.com feedback divider network. OUT 15 ...
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... Amps. For load O MAX ( ) Output Disconnect and Inrush Limiting The LTC3425 is designed to allow true output disconnect by eliminating body diode conduction of the internal PMOS rectifiers. This allows V during shutdown, drawing no current from the input source. It also allows for inrush current limiting at turn-on, minimizing surge currents seen by the input supply ...
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... Converter. Total Area = 0.50in (with All Components Mounted on the Topside of Board) COMPONENT SELECTION Inductor Selection The high frequency, multiphase operation of the LTC3425 allows the use of small surface mount inductors. The minimum inductance value is proportional to the operat- ing frequency and is limited by the following constraints: V • ...
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... Thermal Considerations To deliver the power that the LTC3425 is capable of imperative that a good thermal path be provided to dissi- pate the heat generated within the package. This can be accomplished by taking advantage of the large thermal pad on the underside of the IC ...
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... OUTA V OUTB V OUTC V OUTD LTC3425 FB COMP SS 220pF SYNCOUT PGOOD GNDA GNDB GNDC GNDD D1 TO D4: MOTOROLA MBR0520LT1 L1 TO L4: TDK RLF5018T-2R7M1R8 > 4.3V When Inrush Limiting and Output Disconnect are Not Required OUT LTC3425 www.DataSheet4U.com OUT OUT BULK 2. 4.7 F 150 F ...
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... LTC3425 U U APPLICATIO S I FOR ATIO modulator control to output DC gain, and the error amp open-loop gain gives the DC gain of the system • G • DC CONTROLOUTPUT EA 8 • 000 , CONTROL EA I OUT The output filter pole is given by: I OUT F FILTERPOLE • ...
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... OUTS V OUTA V OUTB V OUTC V OUTD LTC3425 FB COMP C2 SS 220pF SYNCOUT PGOOD C GNDA GNDB GNDC GNDD SS 0. TAIYO YUDEN JMK212BJ475MG ( 4) OUT L1 TO L4: MURATA LQH4C2R2M04 LTC3425 www.DataSheet4U.com R5 10k C1 22pF V OUT 3. OUT 1A BULK R2 R5 4.7 F 150 F 511k 100k 301k R3 PGOOD 100k 3425 TA03 ...
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... 3.3 H 3.3 H 3 SWA SWB SWC SWD IN V OUTS SHDN V OUTA V OUTB REFOUT V OUTC CCM V OUTD REFEN LTC3425 SYNCIN FB BURST COMP SYNCOUT I LIM PGOOD GNDA GNDB GNDC GNDD SGND www.DataSheet4U.com R4 10k C3 22pF V OUT 3.3V C OUT 4.7 F 511k ...
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... U UH Package 32-Lead Plastic QFN (5mm 5mm) (Reference LTC DWG # 05-08-1693) 0.57 0.05 PACKAGE OUTLINE 0.23 0.05 0.50 BSC 0.75 0.05 0.00 – 0.05 3.45 0.10 (4-SIDES) 0.200 REF LTC3425 www.DataSheet4U.com BOTTOM VIEW—EXPOSED PAD R = 0.115 0.40 0.10 TYP (UH) QFN 0102 0.23 0.05 0.50 BSC 3425f ...
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... LTC3425 U TYPICAL APPLICATIO 10MHz, High Current, Very Low Profile, 8-Phase Converter Using Two LTC3425s Operating in Fixed Frequency Mode with Forced CCM (Max Component Height = 1.6mm 2.5V C IN1 2 SWA SWB SWC SWD IN V OUTS SHDN ...