Datasheet

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LTC4359

4359fa

For more information www.linear.com/LTC4359

TYPICAL APPLICATION

FEATURES DESCRIPTION

Ideal Diode Controller with

Reverse Input Protection

The LT C

4359 is a positive high voltage, ideal diode

controller that drives an external N-channel MOSFET to

replace a Schottky diode. It controls the forward-voltage

drop across the MOSFET to ensure smooth current delivery

without oscillation even at light loads. If a power source

fails or is shorted, a fast turn-off minimizes reverse cur

rent transients. A shutdown mode is available to reduce

the quiescent current to 9μA for load switch and 14µA for

ideal diode applications.

When used in high current diode applications, the LTC4359

reduces power consumption, heat dissipation, voltage loss

and PC board area. With its wide operating voltage range,

the ability to withstand reverse input voltage, and high

temperature rating, the LTC4359 satisfies the demanding

requirements

of both automotive and telecom applications.

The LTC4359 also easily ORs power sources in systems

with redundant supplies.

12V, 20A Automotive Reverse-Battery Protection Power Dissipation vs Load Current

APPLICATIONS

Reduces Power Dissipation by Replacing a Power

Schottky Diode

Wide Operating Voltage Range: 4V to 80V

Reverse Input Protection to – 40V

Low 9µA Shutdown Current

Low 150μA Operating Current

Smooth Switchover without Oscillation

Controls Single or Back-to-Back N-Channel MOSFETs

Available in 6-Lead (2mm × 3mm) DFN and 8-Lead

MSOP Packages

Automotive Battery Protection

Redundant Power Supplies

Supply Holdup

Telecom Infrastructure

Computer Systems/Servers

Solar Systems

L, LT , LT C , LTM, Linear Technology and the Linear logo are registered trademarks and

Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the

property of their respective owners.

4359 TA01

LTC4359

SHDN

IN SOURCE OUT

47nF

GATE

BSC028N06NS

SMAT70A

70V

SMAJ24A

24V

12V

OUT

TO LOAD

CURRENT (A)

POWER DISSIPATION (W)

4359 TA01a

SCHOTTKY DIODE (SBG2040CT)

POWER

SAVED

MOSFET (BSC028N06NS)

Summary of content (18 pages)

PAGE 1
LTC4359 Ideal Diode Controller with Reverse Input Protection FEATURES n n n n n n n n DESCRIPTION Reduces Power Dissipation by Replacing a Power Schottky Diode Wide Operating Voltage Range: 4V to 80V Reverse Input Protection to – 40V Low 9µA Shutdown Current Low 150μA Operating Current Smooth Switchover without Oscillation Controls Single or Back-to-Back N-Channel MOSFETs Available in 6-Lead (2mm × 3mm) DFN and 8-Lead MSOP Packages APPLICATIONS n n n n n n Automotive Battery Protection Redundant Power
PAGE 2
LTC4359 ABSOLUTE MAXIMUM RATINGS (Notes 1, 2) IN, SOURCE, SHDN.................................... –40V to 100V OUT (Note 3).................................................–2V to 100V IN – OUT...................................................–100V to 100V IN – SOURCE..................................................–1V to 80V GATE (Note 4)............... VSOURCE –0.3V to VSOURCE +10V Operating Ambient Temperature Range LTC4359C................................................. 0°C to 70°C LTC4359I.......
PAGE 3
LTC4359 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, IN = 12V, SOURCE = IN, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX 80 V 150 9 15 –15 200 20 30 –40 µA µA µA µA 5 120 0.8 0.8 6 7.
PAGE 4
LTC4359 TYPICAL PERFORMANCE CHARACTERISTICS IN Current in Regulation IN Current in Shutdown 200 50 100 50 30 20 TA = 125°C TA = 85°C TA = 25°C TA = –40°C 10 40 20 60 VIN (V) 0 80 0 160 200 VIN = 48V VIN = 12V VIN = 4V IOUT (µA) ISOURCE (µA) 0.5 ∆VSD (V) 50 –1 4359 G04 0.5 –1 –0.5 0 1 0 800 –40 4359 G06 VIN = 12V ∆VSD = 0.
PAGE 5
LTC4359 TYPICAL PERFORMANCE CHARACTERISTICS Gate Turn-Off Time vs Initial Overdrive 200 Gate Turn-Off Time vs Final Overdrive 1500 VIN = 12V ∆VSD = VINITIAL –1V Load Current vs Forward Voltage Drop VIN = 12V ∆VSD = 45mV 10 VFINAL FDB3632 CURRENT (A) tPD (ns) tPD (ns) 1000 100 500 6 4 FDS3732 50 0 FDMS86101 8 150 2 0 0.25 0.5 VINITIAL (V) 0.75 1 0 0 –0.25 –0.5 VFINAL (V) 4359 G10 –0.
PAGE 6
LTC4359 BLOCK DIAGRAM Q1 VIN IN SOURCE VOUT GATE OUT 2.6µA SHDN SHUTDOWN – + CHARGE PUMP TYP. 500kHz – + – FPD COMP + + –1.7V NEGATIVE COMP GATE AMP – + – 30mV VSS IN 30mV 4359 BD 4359fa 6 For more information www.linear.
PAGE 7
LTC4359 OPERATION The LTC4359 controls an external N-channel MOSFET to form an ideal diode. The GATE amplifier (see Block Diagram) senses across IN and OUT and drives the gate of the MOSFET to regulate the forward voltage to 30mV. As the load current increases, GATE is driven higher until a point is reached where the MOSFET is fully on. Further increases in load current result in a forward drop of RDS(ON)• ILOAD.
PAGE 8
LTC4359 APPLICATIONS INFORMATION The MOSFET’s on-resistance, RDS(ON), directly affects the forward voltage drop and power dissipation. Desired forward voltage drop should be less than that of a diode for reduced power dissipation; 100mV is a good starting point. Choose a MOSFET which has: Forward Voltage Drop RDS(ON) < ILOAD 20 MOSFET (BSC028N06NS) CURRENT (A) 15 10 SCHOTTKY DIODE (SBG2040CT) 5 0 The resulting power dissipation is 0 0.1 0.3 0.2 VOLTAGE (V) 0.4 0.5 4359 F02 Figure 2.
PAGE 9
LTC4359 APPLICATIONS INFORMATION Input Short-Circuit Faults LTC4359 SHDN The dynamic behavior of an active, ideal diode entering reverse bias is most accurately characterized by a delay followed by a period of reverse recovery. During the delay phase some reverse current is built up, limited by parasitic resistances and inductances. During the reverse recovery phase, energy stored in the parasitic inductances is transferred to other elements in the circuit.
PAGE 10
LTC4359 APPLICATIONS INFORMATION is not needed. D1, a 70V TVS, protects IN and SOURCE in the positive direction during load steps and overvoltage conditions. OUT can be protected by an output capacitor, COUT of at least 1.5µF, a TVS across the MOSFET or by the MOSFET’s avalanche breakdown. Care must be taken if the MOSFET’s avalanche breakdown is used to protect the OUT pin.
PAGE 11
LTC4359 APPLICATIONS INFORMATION current flow when the MOSFETs are off. Q1 serves as the ideal diode, while Q2 acts as a switch to control forward power flow. On/off control is provided by the SHDN pin, and C1 and R4 may be added if inrush control is desired. 1 S VIN 4 G When SHDN is driven high and provided VIN >VOUT + 30mV, GATE sources 10µA and gradually charges C1, pulling up both MOSFET gates.
PAGE 12
LTC4359 TYPICAL APPLICATIONS Q1 Si4874DY IN 100W SOLAR PANEL SOURCE GATE OUT + SHUNT REGULATOR LTC4359 12V BATTERY LOAD SHDN VSS 4359 F09 Figure 9. Lossless Solar Panel Isolation 1k 0.47µF ES1D D6 SMCJ150A 150V Q1 IPB200N25N3G VIN 48V D4 DDZ9699T 12V CLOAD VOUT 48V 10A R2 2k IN SOURCE GATE OUT D1 SMAT70A 70V LTC4359 SHDN D2 MMSZ5231B VSS 5.
PAGE 13
LTC4359 TYPICAL APPLICATIONS Q2 BSC028N06NS VIN 12V Q1 BSC028N06NS VOUT 12V 10A 12V INPUT CLOAD C1 10nF D2 SMAJ24CA 24V OFF ON R4 10k IN 2M 8.2M R3 10Ω D2 SMAJ24CA 24V IN SOURCE GATE OUT COUT 47nF LTC4359 SHDN Q2 Q1 BSC028N06NS BSC028N06NS UV = 10.8V D3 S1B + – IN– OUT SHDN 10V DDZ9697T REF 4359 F12 SOURCE GATE OUT COUT 1.5µF LTC4359 HYST 1M VSS LTC1540 IN+ OUTPUT VSS 4359 F13 R1 1k V– GND R1 1k Figure 13.
PAGE 14
LTC4359 TYPICAL APPLICATIONS Q1A FDMS86101 Q2A FQA140N10 VINA 28V D1A SMAJ58A 58V D2A SMAJ24A 24V VOUT 28V 10A D4A DDZ9699T 12V IN SOURCE CLOAD GATE OUT COUTA 1.5µF LTC4359 SHDN OFF ON VSS R1A 1k Q2B FQA140N10 VINB 28V D1B SMAJ58A 58V Q1B FDMS86101 D4B DDZ9699T 12V D2B SMAJ24A 24V IN SOURCE GATE OUT COUTB 1.5µF LTC4359 SHDN OFF ON VSS 4359 F16 R1B 1k Figure 16.
PAGE 15
LTC4359 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. DCB Package Package DCB 6-Lead Plastic Plastic DFN (2mm 6-Lead (2mm ××3mm) 3mm) (ReferenceLTC LTC DWG # 05-08-1715 (Reference 05-08-1715Rev RevA)A) 0.70 ±0.05 3.55 ±0.05 1.65 ±0.05 (2 SIDES) 2.15 ±0.05 PACKAGE OUTLINE 0.25 ±0.05 0.50 BSC 1.35 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS R = 0.115 TYP 2.00 ±0.10 (2 SIDES) R = 0.05 TYP 3.00 ±0.
PAGE 16
LTC4359 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. MS8 Package 8-Lead Plastic MSOP (Reference LTC DWG # 05-08-1660 Rev G) 0.889 ±0.127 (.035 ±.005) 5.10 (.201) MIN 3.20 – 3.45 (.126 – .136) 3.00 ±0.102 (.118 ±.004) (NOTE 3) 0.65 (.0256) BSC 0.42 ± 0.038 (.0165 ±.0015) TYP 8 7 6 5 0.52 (.0205) REF RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) 3.00 ±0.102 (.118 ±.004) (NOTE 4) 4.90 ±0.152 (.193 ±.
PAGE 17
LTC4359 REVISION HISTORY REV DATE DESCRIPTION PAGE NUMBER A 08/13 Corrected SHDN pull-up current from 2µA to 2.6µA Updated Figure 11 5, 6, 7, 8 12 4359fa Information 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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. For more information www.linear.
PAGE 18
LTC4359 TYPICAL APPLICATION BACKPLANE PLUG-IN CARD FDB3632 48V LTC4260 Hot Swap™ CONTROLLER VOUT1 DDZ9699T 12V IN SOURCE SHDN SMAT70A 70V GATE OUT LTC4359 1.5µF + CHOLDUP VSS 1k GND 4359 F18 GND Figure 18.