LT4356-3 Linear Technology Corporation, LT4356-3 Datasheet
LT4356-3
Related parts for LT4356-3
LT4356-3 Summary of contents
Page 1
... N-channel MOSFET. The output is limited to a safe value thereby allowing the loads to continue functioning. The LT4356-3 also monitors the voltage drop between the V against overcurrent faults. An internal amplifi er limits the current sense voltage to 50mV ...
Page 2
... LT4356-3 ABSOLUTE MAXIMUM RATINGS , SHDN ................................................ –60V to 100V V CC SNS ............................. V – 30V or –60V FLT, EN...................................... –0.3V to 80V OUT, A OUT GATE (Note 3) .................................–0. FB, TMR, IN ................................................ –0. EN, FLT ...................................................–3mA OUT Operating Temperature Range LT4356C-3 ............................................... 0°C to 70°C LT4356I-3 ............................................ –40°C to 85°C ...
Page 3
... CC From FLT going Low to GATE going Low 80V 1.25V 2mA SINK I = 0.1mA SINK 12V OUT 12V SHDN OUT CC LT4356-3 MIN TYP MAX UNITS 1 μ μ ...
Page 4
... LT4356-3 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T SYMBOL PARAMETER ΔV OUT Pin High Threshold OUT SHDN Pin Threshold V SHDN SHDN Pin Float Voltage V SHDN(FLT) SHDN Pin Current I SHDN t ) Overcurrent Turn Off Delay Time OFF(OC t Overvoltage Turn Off Delay Time ...
Page 5
... V (V) CC GATE Pull-Down Current vs Temperature 12 OVERCURRENT CONDITION ΔV = 120mV SNS 125 –50 – TEMPERATURE (°C) LT4356-3 GATE Pull-Up Current vs Temperature 35 V GATE –50 – TEMPERATURE (°C) 43563 G05 Δ GATE ...
Page 6
... LT4356-3 TYPICAL PERFORMANCE CHARACTERISTICS Specifi cations are 12V 25°C unless otherwise noted ΔV vs Temperature GATE –1μA GATE –50 – 100 TEMPERATURE (°C) 43563 G10 Overcurrent TMR Current vs (V – ...
Page 7
... TEMPERATURE (°C) 500 400 300 FLT EN 200 100 2.0 2.5 3.0 43563 G16 –15 75 100 125 43563 G18 LT4356-3 Overvoltage Turn-Off Time vs Temperature OVERVOLTAGE CONDITION –50 – 100 125 TEMPERATURE (°C) 43563 G17 Reverse Current vs Reverse Voltage –20 V ...
Page 8
... When the OUT pin voltage reaches 0.7V away from V , the EN pin goes high impedance. CC SHDN: Shutdown Control Input. The LT4356-3 can be shut down to a low current mode by pulling the SHDN CC pin below the shutdown threshold of 0.6V. Pull this pin above 1 ...
Page 9
... BLOCK DIAGRAM 50mV – SHDN A OUT – 1.25V AUXILLARY AMPLIFIER + + IN SNS GATE 14V CHARGE PUMP – OC OUT SHDN CONTROL LOGIC GATEOFF – 1.35V 0. TMR – + – 2μA 1.25V TMR LT4356-3 OUT – 1.25V FLT OV EN FLT GND 43563 BD 43563f 9 ...
Page 10
... MOSFET. A higher voltage corresponds to a shorter fault timer period, ensuring the MOSFET operates within its safe operating area (SOA). The LT4356-3 senses an overcurrent condition by monitor- ing the voltage across an optional sense resistor placed between the V and SNS pins ...
Page 11
... APPLICATIONS INFORMATION The LT4356-3 can limit the voltage and current to the load circuitry during supply transients or overcurrent events. The total fault timer period should be set to ride through short overvoltage transients while not causing damage to the pass transistor. The selection of this N-channel MOSFET pass transistor is critical for this application ...
Page 12
... LT4356-3 APPLICATIONS INFORMATION Fault Timer Current The timer current starts at around 2μA with 0.5V or less increasing linearly to 50μA with 75V ing an overvoltage fault (Figure 1). During an overcurrent fault, it starts at 4μA with 0.5V or less 260μA with 80V across the MOSFET (Figure 2). This ...
Page 13
... SHDN low for at least 100μs and pulled high with a slew rate faster than 10V/ms. The FLT output goes high when the fault condition is reset. MOSFET Selection The LT4356-3 drives an N-channel MOSFET to conduct the load current. The important features of the MOSFET are on-resistance R , the maximum drain-source voltage ...
Page 14
... Nevertheless, to account for circuit tolerances this fi gure should be doubled to 13.2W Limiting Inrush Current and GATE Pin Compensation The LT4356-3 limits the inrush current to any load capaci- ⎤ ⎥ tance by controlling the GATE pin voltage slew rate. An ⎥ ...
Page 15
... LT4356-3 43563 F05 Figure 5 Auxiliary Amplifi uncommitted amplifi included in the LT4356-3 to provide fl exibility in the system design. With the negative input connected internally to the 1.25V reference, the am- plifi er can be connected as a level detect comparator with external hysteresis. The open collector output pin capable of driving an opto or LED ...
Page 16
... Figure 8. Overvoltage Regulator with P-Channel MOSFET Reverse Input Protection Shutdown The LT4356-3 can be shut down to a low current mode when the voltage at the SHDN pin goes below the shutdown threshold of 0.6V. The quiescent current drops to 7μA. The SHDN pin can be pulled 60V without damaging the pin ...
Page 17
... V The total overcurrent fault time is value: SNS The power dissipation on Q1 equals to: 14V • 50mV P = These conditions are well within the Safe Operating Area of IRLR2908. is 47nF . LT4356 1.25V • – 1.25V • 380kΩ 1.25V = 14V. CC 47nF • ...
Page 18
... LT4356-3 TYPICAL APPLICATIONS Wide Input Range 5V to 28V Hot Swap with Undervoltage Lockout 24V D2* SMAT70A *DIODES INC SNS 0.02Ω SUD50N03- 118k 10Ω SNS GATE OUT CC 47nF SHDN A OUT + LT4356DE 49.9k GND TMR C TMR 1μF 24V Overvoltage Regulator Withstands 150V at V ...
Page 19
... V SNS GATE OUT 33V + IN 7 SHDN R8 47k LT4356DE FLT OUT GND TMR *DIODES INC. 43563 TA06 TMR 0.1μF LT4356-3 V OUT 12V, 4A CLAMPED AT 16V D1 1N4746A 18V 1W R1 294k 24.9k R6 47k 11 LBO OUT 48V R4 R6 2.5A 140k 100k ...
Page 20
... LT4356-3 TYPICAL APPLICATIONS 2.5A, 28V Hot Swap with Overvoltage Output Regulation at 36V and UV Shutdown at 15V V IN 28V D2* SMAT70A Overvoltage Regulator with Reverse Input Protection Up to –80V V IN 12V D1 1N4148 SNS 15mΩ FDB3632 R3 10Ω C1 6.8nF 1N4700 V SNS GATE ...
Page 21
... EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE DE/UE Package 0.70 0.05 PACKAGE OUTLINE R = 0.115 TYP 0.05 TYP 3.30 0.10 3.00 0.10 (2 SIDES) 1.70 0.10 6 0.25 0.05 0.75 0.05 0.50 BSC 2.50 REF BOTTOM VIEW—EXPOSED PAD 0.00 – 0.05 LT4356-3 0.40 0.10 12 PIN 1 NOTCH R = 0.20 OR 0.35 45 CHAMFER 1 (UE12/DE12) DFN 0806 REV D 43563f 21 ...
Page 22
... LT4356-3 5.23 (.206) MIN 0.305 ± 0.038 (.0120 ± .0015) TYP RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) GAUGE PLANE 0.18 (.007) NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006" ...
Page 23
... N .053 – .069 (1.346 – 1.752) 0 – 8 TYP .014 – .019 (0.355 – 0.483) TYP LT4356-3 .386 – .394 (9.804 – 10.008) NOTE .150 – .157 (3.810 – 3.988) ...
Page 24
... LT4356-3 TYPICAL APPLICATION Overvoltage Regulator with Linear Regulator Up to 100mA 2N2905A V IN 12V D2* SMAJ58A R6 100k *DIODES INC. RELATED PARTS PART NUMBER DESCRIPTION LT1641-1/LT1641-2 Positive High Voltage Hot Swap™ Controllers LTC1696 Overvoltage Protection Controller LTC1735 High Effi ciency Synchronous Step-Down ...