LTC4358IDE-PBF资料

LTC43585A Ideal DiodeFEATURES

n n n n n n nDESCRIPTION

The LTC®4358 is a 5A ideal diode that uses an internal 20mΩ N-channel MOSFET to replace a Schottky diode when used in diode-OR and high current diode applica-tions. The LTC4358 reduces power consumption, heat dissipation, and PC board area. The LTC4358 easily ORs power supplies together to in-crease total system reliability. In diode-OR applications, the LTC4358 regulates the forward voltage drop across the internal MOSFET to ensure smooth current transfer from one path to the other without oscillation. If the power source fails or is shorted, a fast turnoff minimizes reverse current transients.L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.Replaces a Power Schottky DiodeInternal 20mΩ N-Channel MOSFET0.5μs Turn-Off Time Limits Peak Fault CurrentOperating Voltage Range: 9V to 26.5VSmooth Switchover without OscillationNo Reverse DC CurrentAvailable in 14-Pin (4mm × 3mm) DFN and16-Lead TSSOP PackagesAPPLICATIONS

N+1 Redundant Power Suppliesn High Availability Systemsn Telecom Infrastructuren Automotive SystemsnTYPICAL APPLICATION

12V, 5A Diode-OR3.0

VINA = 12VINDRAINOUTLTC4358GNDVDDVOUT TO

5A LOAD

POWER DISSIPATION (W)2.5

DIODE (B530C)2.01.5

POWER SAVED1.00.5

VINB = 12VINDRAIN0

OUTLTC4358GND4358 TA01Power Dissipation vs Load CurrentFET (LTC4358)024CURRENT (A)

684358 TA01b

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LTC4358ABSOLUTE MAXIMUM RATINGS

(Notes 1, 2)Supply Voltages IN, OUT, VDD, DRAIN Voltage .................–0.3V to 28VOutput Voltage GATE (Note 3) ..........................VIN – 0.2V to VIN + 6VOperating Ambient Temperature Range LTC4358C ................................................0°C to 70°C LTC4358I..............................................–40°C to 85°CStorage Temperature Range ...................–65°C to 150°CLead Temperature (Soldering, 10 sec) E Package .......................................................300°CPIN CONFIGURATION

TOP VIEWTOP VIEWININININGATENCGND123456715DRAIN14IN13IN12IN11IN10NC9OUT8VDDININININNCGATENCGNDDE PACKAGE14-LEAD (4mm s 3mm) PLASTIC DFNTJMAX = 125°C, θJC = 4°C/W, θJA = 43°C/W1234567817DRAIN16IN15IN14IN13IN12IN11NC10OUT9VDDFE PACKAGE16-LEAD PLASTIC TSSOPFTJMAX = 125°C, θJC = 10°C/W, θJA = 38°C/WORDER INFORMATION

LEAD FREE FINISHLTC4358CDE#PBFLTC4358IDE#PBFLTC4358CFE#PBFLTC4358IFE#PBFTAPE AND REELLTC4358CDE#TRPBFLTC4358IDE#TRPBFLTC4358CFE#TRPBFLTC4358IFE#TRPBFPART MARKING*435843584358FE4358FEPACKAGE DESCRIPTION14-Lead (4mm × 3mm) Plastic DFN14-Lead (4mm × 3mm) Plastic DFN16-Lead Plastic TSSOP16-Lead Plastic TSSOPTEMPERATURE RANGE0°C to 70°C–40°C to 85°C0°C to 70°C–40°C to 85°CConsult LTC Marketing for parts specifi ed with wider operating temperature ranges. *Temperature grades are identifi ed by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based fi nish parts.For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/4358fa2元器件交易网www.cecb2b.com

LTC4358ELECTRICAL CHARACTERISTICS The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at TA = 25°C. VOUT = VDD, VDD = 9V to 26.5V, unless otherwise noted.SYMBOLVDDIDDIINIOUTIDRAINΔVGATEIGATE(UP)IGATE(DOWN)tONtOFFΔVSDΔVSDRDS(ON)PARAMETEROperating Supply RangeOperating Supply CurrentIN Pin CurrentOUT Pin CurrentDRAIN Pin CurrentN-Channel Gate Drive (VGATE – VIN)N-Channel Gate Pull Up CurrentN-Channel Gate Pull DownCurrent in Fault ConditionTurn-On TimeTurn-Off TimeSource-Drain Regulation Voltage(VIN – VOUT)Body Diode Forward Voltage DropInternal N-Channel MOSFET On ResistanceVIN = VOUT ± 1V, No LoadVIN = VOUT ± 1V, No LoadVIN = 0V, VOUT = VDD = VDRAIN = 26.5VVDD, VOUT = 9V to 26.5VVGATE = VIN, VIN – VOUT = 0.1VVGATE = VIN + 5V–VIN – VOUT = –1V –| 0.1V, VDRAIN = VIN, VOUT = VDD, VGATE – VIN > 4.5V–VIN – VOUT = 55mV |– –1V, VDRAIN = VIN, VOUT = VDD, VGATE – VIN < 1VCONDITIONSlllllllllllllMIN9150TYPMAX26.50.6UNITSVmAμAμAμAμAVμAA3508045016051504.5–141–202200300100.6250.82015–2650050055140μsnsmVVmΩ1mA < IIN < 100mAIIN = 5A, MOSFET OffIIN = 5ANote 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime.Note 2: All currents into pins are positive, all voltages are referenced to GND unless otherwise specifi ed.Note 3: An internal clamp limits the GATE pin to a minimum of 6V above IN. Driving this pin to voltages beyond this clamp may damage the device.4358fa3元器件交易网www.cecb2b.com

LTC4358TYPICAL PERFORMANCE CHARACTERISTICS

VDD Current (IDD vs VDD)500VIN = VOUT = VDD300IOUT (μA)400IN Current (IIN vs VIN)VIN = VOUT = VDD100OUT Current (IOUT vs VOUT)VIN = VOUT = VDD40080IDD (μA)IIN (μA)3006020020010010040200010VDD (V)20304358 G010010VIN (V)20304358G020010VOUT (V)20304358G03MOSFET RDS(ON) vs Temperature30IIN = 5A25VOUT = VDD = 9VRDS(ON) (mΩ)2015VOUT = VDD = 26.5V1010050-500tPD (ns)300400FET Turn-Off Time vs Initial Overdrive2000FET Turn-Off Time vs Final OverdriveVIN = 12V$VSD= 55mV1500VFINALtPD (ns)-1V200VIN = 12V$VSD= VINITIAL1000500-25025507510012500.20.40.60.814358 G0500-0.2-0.4-0.6-0.8-14358 G06TEMPERATURE (˚C)4358 G04VINITIAL (V)VFINAL (V)4358fa4元器件交易网www.cecb2b.com

LTC4358PIN FUNCTIONS

(DE/FE PACKAGES)DRAIN: The exposed pad is the drain of the internal N-channel MOSFET. This pin must be connected to OUT (Pin 9/Pin 10).GATE: Gate Drive Output. If reverse current fl ows, a fast pulldown circuit quickly connects the GATE pin to the IN pin, turning off the MOSFET. Leave open if unused.GND: Device Ground.IN: Input Voltage and Fast Pulldown Return. IN is the anode of the ideal diode. The voltage sensed at this pin is used to control the source-drain voltage drop across the internal MOSFET. If reverse current starts to fl ow, a fast pulldown circuit quickly turns off the internal MOSFET. The fast pulldown current is returned through this pin.NC: No Connection. Not internally connected.OUT: Output Voltage. The OUT pin is the cathode of the ideal diode and the common output when multiple LTC4358s are confi gured as an ideal diode-OR. The voltage sensed –at this pin is used to control the source-drain voltage drop +

across the MOSFET. Connect this pin to the drain of the internal N-channel MOSFET (Pin 15/Pin 17).VDD: Positive Supply Input. The LTC4358 is powered from the VDD pin. Connect this pin to OUT either directly or through an RC hold-up circuit.BLOCK DIAGRAM

DRAININGATEOUTCHARGE PUMPFPDCOMPGATEAMPIN25mVVDD+–25mV+–+–GND4358 BD4358fa5元器件交易网www.cecb2b.com

LTC4358OPERATION

High availability systems often employ parallel-connected power supplies or battery feeds to achieve redundancy and enhance system reliability. ORing diodes have been a popular means of connecting these supplies at the point of load. The disadvantage of this approach is the forward voltage drop and resulting effi ciency loss. This drop reduces the available supply voltage and dissipates signifi cant power. Using an N-channel MOSFET to replace a Schottky diode reduces the power dissipation and eliminates the need for costly heat sinks or large thermal layouts in high power applications.The LTC4358 is a single positive voltage ideal diode con-troller that drives an internal N-channel MOSFET as a pass transistor to replace a Schottky diode. The IN and DRAIN pins form the anode and cathode of the ideal diode. The input supply is connected to the IN pins, while the DRAIN pin serves as the output. The OUT pin is connected directly to DRAIN and VDD. VDD is the supply for the LTC4358 and is derived from the output either directly or through an RC hold-up circuit.At power-up, the load current initially fl ows through the body diode of the internal MOSFET. The internal MOSFET turns on and the amplifi er tries to regulate the voltage drop across the IN and OUT connections to 25mV. If the load current causes more than 25mV of drop, the MOSFET is driven fully on and the voltage drop is equal toRDS(ON) • ILOAD. If the load current is reduced causing the forward drop to fall below 25mV, the internal MOSFET is driven lower by a weak pull-down in an attempt to maintain the drop at 25mV. If the load current reverses the MOSFET is turned off with a strong pull-down.In the event of a power supply failure, such as if the sup-ply that is conducting most or all of the current is shorted to ground, reverse current temporarily fl ows through the LTC4358 ideal diode that is on. This current is sourced from any load capacitance and from the other supplies. The ideal diode is turned off within 500ns, preventing reverse current from slewing up to a damaging level and minimizing any disturbance on the output.4358fa6元器件交易网www.cecb2b.com

LTC4358APPLICATIONS INFORMATION

ORing Two Supply OutputsWhere LTC4358s are used to combine the outputs of two supplies, the power supply with the highest output voltage sources most or all of the current. If this supply’s output is quickly shorted to ground while delivering load current, the current temporarily reverses and fl ows backwards through the LTC4358. When reverse current fl ows the LTC4358 ideal diode is quickly turned off.If the other initially lower supply was not delivering load current at the time of the fault, the output falls until the LTC4358 body diode conducts. Meanwhile, the internal amplifi er turns on the MOSFET until the forward drop is reduced to 25mV. If instead this supply was delivering load current at the time of the fault, its ORing MOSFET was already driven at least partially on, and will be driven harder in an effort to maintain a drop of 25mV.Load SharingFigure 1 combines the outputs of multiple, redundant supplies using a simple technique known as droop sharing. Load current is fi rst taken from the highest output, with the low outputs contributing as the output voltage falls under increased loading. The 25mV regulation technique ensures smooth load sharing between outputs without oscillation. The degree of sharing depends on the 20mΩ resistance of the LTC4358 internal MOSFET, the output impedance of the supplies and their initial output voltages.VINA = 12VPS1RTNALTC4358GNDOUTVDDINDRAIN12V BUS

VINB = 12VPS2RTNBINDRAINOUTLTC4358GNDVDDVINC = 12VPS3RTNCINDRAINOUTLTC4358GND4358 F01VDDFigure 1. Droop Sharing Redundant Supplies4358fa7元器件交易网www.cecb2b.com

LTC4358APPLICATIONS INFORMATION

VDD Hold-Up CircuitIn the event of an input short, parasitic inductance between the input supply of the LTC4358 and the load bypass capacitor may cause VDD to glitch below its minimum operating voltage. This causes the turn-off time (tOFF) to increase. To preserve the fast turn-off time, local output bypassing of 39μF or more is suffi cient or a 100Ω, 0.1μF RC hold-up circuit on the VDD pin can be used as shown in Figure 2a and Figure 2b.Layout ConsiderationsThe following advice should be considered when laying out a printed circuit board for the LTC4358: The OUT pin should (a)VIN = 12VINDRAINOUTLTC4358GNDVDDCBYPASS39MFMMBD1205LTC4358VDDGNDC10.1μFbe connected as closely as possible to the EXPOSED PAD (drain of the MOSFET) for good accuracy. Keep the traces to the IN and DRAIN wide and short. The PCB traces as-sociated with the power path through the MOSFET should have low resistance. See Figure 4.The DRAIN acts as a heatsink to remove the heat from the device. For a single layer PCB with the DFN package, use Figure 5 to determine the PCB area needed for a speci-fi ed maximum current and ambient temperature. If using a two sided PCB, the maximum current is increased by 10%. If the FE package is used, the maximum current is increased by 4%.VOUT

VIN = 12VINDRAINOUTR1100ΩVOUT12V5ACLOAD

4358 F03(b)VIN = 12VINDRAINOUTLTC4358GND4358 F02VOUT

R11007C10.1MFFigure 3. –12V Reverse Input ProtectionVDDFigure 2. Two Methods of Protecting Against Collapse of VDD From Input Short and Stray Inductance4358fa8元器件交易网www.cecb2b.com

LTC4358APPLICATIONS INFORMATION

VIN

GND

VOUT

Figure 4. DFN Layout Considerations for 1” × 1” Single Sided PCB10

85oCTA = 70oC50oC25oCAREA (INCH2)1

0.13.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

DIODE CURRENT (A)

4358 F05

Figure 5. Maximum Diode Current vs PCB Area4358fa9元器件交易网www.cecb2b.com

LTC4358PACKAGE DESCRIPTION

DE Package14-Lead Plastic DFN (4mm × 3mm)(Reference LTC DWG # 05-08-1708)0.70 ±0.053.30 ±0.051.70 ± 0.05PACKAGEOUTLINE0.25 ± 0.050.50 BSC3.00 REFRECOMMENDED SOLDER PAD PITCH AND DIMENSIONSAPPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED

3.60 ±0.052.20 ±0.054.00 ±0.10(2 SIDES)R = 0.05TYPR = 0.115TYP8140.40 ± 0.103.00 ±0.10(2 SIDES)PIN 1TOP MARK(SEE NOTE 6)3.30 ±0.101.70 ± 0.10PIN 1 NOTCHR = 0.20 OR0.35 × 45°CHAMFER (DE14) DFN 0806 REV B

70.200 REF0.75 ±0.053.00 REF0.00 – 0.0510.25 ± 0.050.50 BSCBOTTOM VIEW—EXPOSED PAD

NOTE:

1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WGED-3) IN JEDECPACKAGE OUTLINE MO-2292.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 0.15mm ON ANY SIDE5. EXPOSED PAD SHALL BE SOLDER PLATED

6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE

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LTC4358PACKAGE DESCRIPTION

FE Package16-Lead Plastic TSSOP (4.4mm)(Reference LTC DWG # 05-08-1663)Exposed Pad Variation BC3.58(.141) 4.90 – 5.10*(.193 – .201)3.58(.141)1615141312111096.60 ±0.104.50 ±0.10SEE NOTE 42.94(.116)0.45 ±0.051.05 ±0.100.65 BSC6.402.94(.252)(.116)BSCRECOMMENDED SOLDER PAD LAYOUT

123456781.10(.0433)MAX0° – 8°

4.30 – 4.50*(.169 – .177)0.25REF0.09 – 0.20(.0035 – .0079)0.50 – 0.75(.020 – .030)0.65(.0256)BSCNOTE:

1. CONTROLLING DIMENSION: MILLIMETERS

MILLIMETERS

2. DIMENSIONS ARE IN

(INCHES)3. DRAWING NOT TO SCALE

0.195 – 0.30(.0077 – .0118)TYP

0.05 – 0.15(.002 – .006)FE16 (BC) TSSOP 02044. RECOMMENDED MINIMUM PCB METAL SIZE FOR EXPOSED PAD ATTACHMENT

*DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.150mm (.006\") PER SIDE

4358faInformation 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.11元器件交易网www.cecb2b.com

LTC4358TYPICAL APPLICATION

Plug-In Card Input Diode for Supply Hold-UpBACKPLANEPLUG-IN CARDCONNECTORSCONNECTOR 112VINOUTHOT SWAPCONTROLLER100ΩVOUT1

LTC4358GNDVDD0.1μF+CHOLDUPGNDINOUTHOT SWAPCONTROLLER100ΩVOUT2

LTC4358GNDVDD0.1μF+CHOLDUPGND4358 TA02PLUG-IN CARDCONNECTOR 2

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PART NUMBERLT10AH/LT10ALLT11-1/LT11-2LT4250LTC4251/LTC4251-1/LTC4251-2LTC4252-1/LTC4252-2/LTC4252-1A/LTC4252-2ALTC4253LT4256LTC4260LTC4261LTC4350LT4351LTC4352LTC4354LTC4355LTC4357LTC4223-1/LTC4223-2DESCRIPTIONNegative High Voltage Hot Swap™ Controllers in SO-8Positive High Voltage Hot Swap Controllers–48V Hot Swap Controller–48V Hot Swap Controllers in SOT-23–48V Hot Swap Controllers in MS8/MS10–48V Hot Swap Controller with SequencerPositive 48V Hot Swap Controller with Open-Circuit DetectPositive High Voltage Hot Swap ControllerNegative High Voltage Hot Swap ControllerHot Swappable Load Share ControllerMOSFET Diode-OR ControllerIdeal Diode Controller with MonitorNegative Voltage Diode-OR Controller and MonitorPositive Voltage Diode-OR Controller and MonitorPositive High Voltage Ideal Diode ControllerCOMMENTSNegative High Voltage Supplies From –10V to –80VActive Current Limiting, Supplies From 9V to 80VActive Current Limiting, Supplies From –20V to –80VFast Active Current Limiting, Supplies From –15VFast Active Current Limiting, Supplies From –15V, Drain Accelerated ResponseFast Active Current Limiting, Supplies From –15V, Drain Accelerated Response, Sequenced Power Good OutputsFoldback Current Limiting, Open-Circuit and Overcurrent Fault Output, Up to 80V SupplyWith I2C and ADC, Supplies from 8.5V to 80VWith I2C and 10-Bit ADC, Adjustable Inrush and Overcurrent LimitsOutput Voltage: 1.2V to 20V, Equal Load SharingExternal N-Channel MOSFETs Replace ORing Diodes, 1.2V to 20VControls N-Channel MOSFET, 0V to 18V OperationControls Two N-Channel MOSFETs, 1μs Turn-Off, 80V OperationControls Two N-Channel MOSFETs, 0.5μs Turn-Off, 80V OperationControls Single N-Channel MOSFET, 0.5μs Turn-Off, 80V OperationControls 12V Main and 3.3V Auxiliary SuppliesDual Supply Hot Swap Controller for Advanced Mezzanine Cards and μTCAHot Swap is a trademark of Linear Technology Corporation.4358fa12Linear Technology CorporationLT 0808 REV A • PRINTED IN USA

1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com© LINEAR TECHNOLOGY CORPORATION 2007