LT4356MP-1/LT4356MP-2 Surge Stopper FEATURES DESCRIPTION n Stops High Voltage Surges The LT®4356 surge stopper protects loads from high volt- n Adjustable Output Clamp Voltage age transients. It regulates the output during an overvolt- n Overcurrent Protection age event, such as load dump in automobiles, by control- n Wide Operation Range: 4V to 80V ling the gate of an external N-channel MOSFET. The output n Reverse Input Protection to –60V is limited to a safe value thereby allowing the loads to n Low 7µA Shutdown Current, LT4356-1 continue functioning. The LT4356MP also monitors the n Adjustable Fault Timer voltage drop between the V and SNS pins to protect CC n Controls N-Channel MOSFET against overcurrent faults. An internal amplifier limits the n Shutdown Pin Withstands –60V to 100V current sense voltage to 50mV. In either fault condition, a n Fault Output Indication timer is started inversely proportional to MOSFET stress. n Guaranteed Operation –55°C to 125°C If the timer expires, the FLT pin pulls low to warn of an n Auxiliary Amplifier for Level Detection Comparator or impending power-down. If the condition persists, the Linear Regulator Controller MOSFET is turned off. After a cooldown period, the GATE n Available in 10-Pin MSOP or 16-Pin SO Packages pin pulls up turning on the MOSFET again. The auxiliary amplifier may be used as a voltage detection APPLICATIONS comparator or as a linear regulator controller driving an external PNP pass transistor. n Automotive/Avionic Surge Protection n Hot Swap/Live Insertion Back-to-back FETs can be used in lieu of a Schottky diode n High Side Switch for Battery Powered Systems for reverse input protection, reducing voltage drop and n Intrinsic Safety Applications power loss. A shutdown pin reduces the quiescent current to less than 7µA for the LT4356-1 during shutdown. The L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and No RSENSE and ThinSOT are trademarks of Analog Devices, Inc. All other trademarks are the LT4356-2 differs from the LT4356-1 during shutdown by property of their respective owners. reducing the quiescent current to 60µA and keeping alive the auxiliary amplifier for uses such as an undervoltage lockout or always-on regulator. TYPICAL APPLICATION 4A, 12V Overvoltage Output Regulator Overvoltage Protector Regulates Output at 27V During Transient VIN 10mΩ IRLR2908 VOUT 12V 80V INPUT SURGE CTMR = 6.8µF ILOAD = 500mA 10Ω 102k VIN VCC SNS GATE OUT 20V/DIV 383k FB SHDN 4.99k VCC 12V 27V ADJUSTABLE CLAMP IN+ LT4356S CONDVCE-DRCTER VOUT 20V/DIV 100k 12V EN SHDN GND UNDERVOLTAGE AOUT GND TMR FLT FAULT 100ms/DIV 4356mp12 TA01b 4356mp12 TA01 0.1µF 4356mp12fc 1 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 ABSOLUTE MAXIMUM RATINGS (Notes 1 and 2) V , SHDN ................................................–60V to 100V Operating Temperature Range CC SNS .............................V – 30V or –60V to V + 0.3V LT4356M ............................................–55°C to 125°C CC CC OUT, A , FLT, EN .....................................–0.3V to 80V Storage Temperature Range OUT GATE (Note 3) .................................–0.3V to V + 10V MS, SO ..............................................–65°C to 150°C OUT FB, TMR, IN+ ................................................–0.3V to 6V Lead Temperature (Soldering, 10 sec) A , EN, FLT, IN+..................................................–3mA MS, SO .............................................................300°C OUT PIN CONFIGURATION TOP VIEW TMR 1 16 IN+ FB 2 15 NC TOP VIEW FB 1 10 TMR NC 3 14 AOUT OUT 2 9 GND OUT 4 13 NC GATE 3 8 EN SNS 4 7 FLT GATE 5 12 GND VCC 5 6 SHDN NC 6 11 EN MS PACKAGE SNS 7 10 FLT 10-LEAD PLASTIC MSOP TJMAX = 125°C, θJA = 160°C/W VCC 8 9 SHDN S PACKAGE 16-LEAD PLASTIC SO TJMAX = 150°C, θJA = 100°C/W ORDER INFORMATION http://www.linear.com/product/LT4356MP-1#orderinfo LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT4356MPMS-1#PBF LT4356MPMS-1#TRPBF LTFGD 10-Lead Plastic MSOP –55°C to 125°C LT4356MPS-1#PBF LT4356MPS-1#TRPBF LT4356MPS-1 16-Lead Plastic SO –55°C to 125°C LT4356MPS-2#PBF LT4356MPS-2#TRPBF LT4356MPS-2 16-Lead Plastic SO –55°C to 125°C LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT4356MPMS-1 LT4356MPMS-1#TR LTFGD 10-Lead Plastic MSOP –55°C to 125°C LT4356MPS-1 LT4356MPS-1#TR LT4356MPS-1 16-Lead Plastic SO –55°C to 125°C LT4356MPS-2 LT4356MPS-2#TR LT4356MPS-2 16-Lead Plastic SO –55°C to 125°C Consult LTC Marketing for parts specified with wider operating temperature ranges. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix. 4356mp12fc 2 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25°C. V = 12V unless otherwise noted. A CC SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Operating Voltage Range l 4 80 V CC I V Supply Current V = Float l 1 1.5 mA CC CC SHDN V = 0V, IN+ = 1.3V, LT4356MP-1 7 25 µA SHDN LT4356MP-1 l 7 40 µA V = 0V, IN+ = 1.3V, LT4356MP-2 60 70 µA SHDN LT4356MP-2 l 60 250 µA I Reverse Input Current V = V = –30V, SHDN Open l 0.3 1 mA R SNS CC V = V = V = –30V l 0.8 2 mA SNS CC SHDN ΔV GATE Pin Output High Voltage V = 4V; (V – V ) l 4.5 8 V GATE CC GATE OUT 80V ≥ V ≥ 8V; (V – V ) l 10 16 V CC GATE OUT I GATE Pin Pull-Up Current V = 12V; V = 12V l –4 –23 –38 µA GATE(UP) GATE CC V = 48V; V = 48V l –4.5 –30 –50 µA GATE CC I GATE Pin Pull-Down Current Overvoltage, V = 1.4V, V = 12V l 75 150 mA GATE(DN) FB GATE Overcurrent, V – V = 120mV, V = 12V l 5 10 mA CC SNS GATE Shutdown Mode, V = 0V, V = 12V l 1.5 5 mA SHDN GATE V FB Pin Servo Voltage V = 12V; V = 12V l 1.215 1.25 1.275 V FB GATE OUT I FB Pin Input Current V = 1.25V l 0.3 1 µA FB FB ΔV Overcurrent Fault Threshold ΔV = (V – V ), V = 12V l 42.5 50 55 mV SNS SNS CC SNS CC ΔV = (V – V ), V = 48V l 43 51 56 mV SNS CC SNS CC I SNS Pin Input Current V = V = 12V to 48V l 5 10 22 µA SNS SNS CC I FLT, EN Pins Leakage Current FLT, EN = 80V l 2.5 µA LEAK A Pin Leakage Current A = 80V 4.5 µA OUT OUT I TMR Pin Pull-Up Current V = 1V, V = 1.5V, (V – V ) = 0.5V l –1.5 –2.5 –4 µA TMR TMR FB CC OUT V = 1V, V = 1.5V, (V – V ) = 75V l –44 –50 –56 µA TMR FB CC OUT V = 1.3V, V = 1.5V l –3.5 –5.5 –8.5 µA TMR FB V = 1V, ΔV = 60mV, (V – V ) = 0.5V l –2.5 –4.5 –6.5 µA TMR SNS CC OUT V = 1V, ΔV = 60mV, (V – V ) = 80V l –195 –260 –315 µA TMR SNS CC OUT TMR Pin Pull-Down Current V = 1V, V = 1V, ΔV = 0V l 1.5 2.2 2.7 µA TMR FB SNS V TMR Pin Thresholds FLT From High to Low, V = 5V to 80V l 1.22 1.25 1.28 V TMR CC V From Low to High, V = 5V to 80V l 0.48 0.5 0.52 V GATE CC ΔV Early Warning Period From FLT Going Low to GATE Going Low, V = 5V to 80V l 80 100 120 mV TMR CC V + IN+ Pin Threshold l 1.22 1.25 1.28 V IN I + IN+ Pin Input Current V + = 1.25V l 0.3 1 µA IN IN V FLT, EN Pins Output Low I = 2mA l 2 8 V OL SINK I = 0.1mA l 300 800 mV SINK A Pin Output Low I = 2mA l 2 8 V OUT SINK I = 0.1mA l 200 400 mV SINK 4356mp12fc 3 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25°C. V = 12V unless otherwise noted. A CC SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS I OUT Pin Input Current V = V = 12V l 200 300 µA OUT OUT CC V = V = 12V, V = 0V l 6 14 mA OUT CC SHDN ΔV OUT Pin High Threshold ΔV = V – V ; EN from Low to High l 0.25 0.5 0.7 V OUT OUT CC OUT V SHDN Pin Threshold V = 12V to 48V 0.6 1.4 1.7 V SHDN CC l 0.4 2.1 V V SHDN Pin Float Voltage V = 12V to 48V l 0.6 1.2 2.1 V SHDN(FLT) CC I SHDN Pin Current V = 0V l –1 –4 –8 µA SHDN SHDN t ) Overcurrent Turn-Off Delay Time GATE from High to Low, ΔV = 0 → 120mV l 2 4 µs OFF(OC SNS t Overvoltage Turn-Off Delay Time GATE from High to Low, V = 0 → 1.5V l 0.25 1 µs OFF(OV) FB Note 1: Stresses beyond those listed under Absolute Maximum Ratings Note 2: All currents into device pins are positive; all currents out of device may cause permanent damage to the device. Exposure to any Absolute pins are negative. All voltages are referenced to GND unless otherwise Maximum Rating condition for extended periods may affect device specified. reliability and lifetime. Note 3: An internal clamp limits the GATE pin to a minimum of 10V above the OUT pin. Driving this pin to voltages beyond the clamp may damage the device. TYPICAL PERFORMANCE CHARACTERISTICS Specifications are at V = 12V, T = 25°C unless otherwise noted. CC A I vs V I (Shutdown) vs V I (Shutdown) vs V CC CC CC CC CC CC 1000 60 120 LT4356-1 LT4356-2 IN+ = 1.3V 50 100 800 40 80 600 A) A) A) (µC (µC 30 (µC 60 C C C I 400 I I 20 40 200 10 20 0 0 0 0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80 VCC (V) VCC (V) VCC (V) 4356mp12 G01 4356mp12 G02 4356mp12 G03 4356mp12fc 4 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 TYPICAL PERFORMANCE CHARACTERISTICS Specifications are at V = 12V, T = 25°C unless otherwise noted. CC A I (Shutdown) vs Temperature I (Shutdown) vs Temperature SHDN Current vs Temperature CC CC 35 300 6 LT4356-1 LT4356-2 VSHDN = 0V 30 250 5 25 200 4 A) 20 A) µA) (µC (µC150 (DN 3 IC 15 IC SH I 100 2 10 5 50 1 0 0 0 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 4356mp12 G04 4356mp12 G05 4356mp12 G06 GATE Pull-Up Current GATE Pull-Down Current GATE Pull-Up Current vs V vs Temperature vs Temperature CC 40 35 220 VGATE = VOUT = 12V OVERVOLTAGE CONDITION 35 30 VFB = 1.5V 200 30 25 A)180 25 m I (µA)GATE 2105 I (µA)GATE 1250 (ATE(DOWN)160 G140 10 I 10 5 5 120 0 0 100 0 10 20 30 40 50 60 70 80 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 VCC (V) TEMPERATURE (°C) TEMPERATURE (°C) 4356mp12 G07 4356mp12 G08 4356mp12 G09 GATE Pull-Down Current vs Temperature ΔVGATE vs IGATE ΔVGATE vs Temperature 12 14 14 OVERCURRENT CONDITION VOUT = 12V IGATE = –1µA ∆VSNS = 120mV 10 12 12 VCC = 8V 10 10 A) 8 m (OWN) 6 (V)ATE 8 (V)ATE 8 ATE(D ∆VG 6 ∆VG 6 IG 4 4 4 VCC = 4V 2 2 2 0 0 0 –50 –25 0 25 50 75 100 125 0 2 4 6 8 10 12 14 16 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) IGATE (µA) TEMPERATURE (°C) 4356mp12 G10 4356mp12 G11 4356mp12 G12 4356mp12fc 5 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 TYPICAL PERFORMANCE CHARACTERISTICS Overvoltage TMR Current Overcurrent TMR Current ΔVGATE vs VCC vs (VCC – VOUT) vs (VCC – VOUT) 16 48 280 OVERVOLTAGE CONDITION OVERCURRENT CONDITION 14 TA = 130°C 40 VVOTMUTR == 51VV 240 VVOTMUTR == 01VV 12 TA = –45°C 200 32 (V)GATE180 TA = 25°C (µA)MR 24 (µA)MR160 ∆V 6 IT IT120 16 80 4 8 2 IGATE = –1µA 40 VOUT = VCC 0 0 0 0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80 VCC (V) VCC – VOUT (V) VCC – VOUT (V) 4356mp12 G13 4356mp12 G14 4356mp12 G15 Warning Period TMR Pull-Down Current TMR Current vs V vs Temperature Output Low Voltage vs Current CC 14 3.0 4.0 OVERVOLTAGE, EARLY VTMR = 1V WARNING PERIOD 12 VFB = 1.5V 2.5 3.5 AOUT VTMR = 1.3V 3.0 10 2.0 2.5 I (µA)TMR 68 I (µA)TMR1.5 V (V)OL 21..05 FLT EN 1.0 4 1.0 0.5 2 0.5 0 0 0 0 10 20 30 40 50 60 70 80 –50 –25 0 25 50 75 100 125 0 0.5 1.0 1.5 2.0 2.5 3.0 VCC (V) TEMPERATURE (°C) CURRENT (mA) 4356mp12 G16 4356mp12 G17 4356mp12 G18 Overvoltage Turn-Off Time Overcurrent Turn-Off Time Reverse Current vs Temperature vs Temperature vs Reverse Voltage 500 4.0 –20 OVERVOLTAGE CONDITION OVERCURRENT CONDITION VCC = SNS VFB = 1.5V ∆VSNS = 120mV 3.5 400 –15 3.0 ns)300 µs) mA) t (OFF200 t (OFF 2.5 I (CC–10 2.0 –5 100 1.5 0 1.0 0 –50 –25 0 25 50 75 100 125 –50 –25 0 25 50 75 100 125 0 –20 –40 –60 –80 TEMPERATURE (°C) TEMPERATURE (°C) VCC (V) 4356mp12 G19 4356mp12 G20 4356mp12 G21 4356mp12fc 6 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 PIN FUNCTIONS A (SO Package Only): Amplifier Output. Open collector OUT: Output Voltage Sense Input. This pin senses the OUT output of the auxiliary amplifier. It is capable of sinking voltage at the source of the N-channel MOSFET and sets up to 2mA from 80V. The negative input of the amplifier the fault timer current. When the OUT pin voltage reaches is internally connected to a 1.25V reference. 0.7V away from V , the EN pin goes high impedance. CC EN: Open-Collector Enable Output. The EN pin goes high SHDN: Shutdown Control Input. The LT4356 can be shut impedance when the voltage at the OUT pin is above (V down to a low current mode by pulling the SHDN pin CC – 0.7V), indicating the external MOSFET is fully on. The below 0.4V. Pull this pin above 2.1V or disconnect it and state of the pin is latched until the OUT pin voltage resets allow the internal current source to turn the part back on. at below 0.5V and goes back up above 2V. The internal The leakage current to ground at the pin should be limited NPN is capable of sinking up to 3mA of current from 80V to no more than 1µA if no pull-up device is used to turn to drive an LED or opto-coupler. the part on. The SHDN pin can be pulled up to 100V or below GND by 60V without damage. In shutdown, the FB: Voltage Regulator Feedback Input. Connect this pin auxiliary amplifier turns off in the LT4356-1 but continues to the center tap of the output resistive divider connected operating in the LT4356-2. between the OUT pin and ground. During an overvoltage condition, the GATE pin is servoed to maintain a 1.25V SNS: Current Sense Input. Connect this pin to the out- threshold at the FB pin. This pin is clamped internally to put of the current sense resistor. The current limit circuit 7V. Tie to GND to disable the OV clamp. controls the GATE pin to limit the sense voltage between V and SNS pins to 50mV. At the same time the sense FLT: Open-Collector Fault Output. This pin pulls low after CC amplifier also starts a current source to charge up the the voltage at the TMR pin has reached the fault thresh- TMR pin. This pin can be pulled below GND by up to 60V, old of 1.25V. It indicates the pass transistor is about to though the voltage difference with the V pin must be turn off because either the supply voltage has stayed at CC limited to less than 30V. Connect to V if unused. an elevated level for an extended period of time (volt- CC age fault) or the device is in an overcurrent condition TMR: Fault Timer Input. Connect a capacitor between (current fault). The internal NPN is capable of sink- this pin and ground to set the times for early warning, ing up to 3mA of current from 80V to drive an LED or fault and cooldown periods. The current charging up this opto-coupler. pin during fault conditions depends on the voltage differ- ence between the V and OUT pins. When V reaches GATE: N-channel MOSFET Gate Drive Output. The GATE CC TMR 1.25V, the FLT pin pulls low to indicate the detection of a pin is pulled up by an internal charge pump current source fault condition. If the condition persists, the pass transis- and clamped to 14V above the OUT pin. Both voltage and tor turns off when V reaches the threshold of 1.35V. current amplifiers control the GATE pin to regulate the TMR As soon as the fault condition disappears, the pull-up output voltage and limit the current through the MOSFET. current stops and a 2µA current starts to pull the TMR pin GND: Device Ground. down. When V reaches the retry threshold of 0.5V, the TMR IN+ (SO Package Only): Positive Input of the Auxiliary GATE pin pulls high turning back on the pass transistor. A minimum of 10nF capacitor is needed to compensate Amplifier. This amplifier can be used as a level detection the loop. A 10V rated X7R capacitor is recommended for comparator with external hysteresis or linear regulator C . controlling an external PNP transistor. This pin is clamped TMR internally to 7V. Connect to ground if unused. V : Positive Supply Voltage Input. The positive supply CC input ranges from 4V to 80V for normal operation. It can also be pulled below ground potential by up to 60V during a reverse battery condition, without damaging the part. The supply current is reduced to 7µA with all the func- tional blocks off. 4356mp12fc 7 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 BLOCK DIAGRAM VCC SNS GATE OUT + 14V 50mV – CHARGE PUMP FB + – + VA IA – 1.25V SHDN FLT AOUT OC OUT OV – 1.25V SHDN AUXILIARY CONTROL EN AMPLIFIER LOGIC + RESTART GATEOFF FLT IN+ 1.35V – VCC + 0.5V + ITMR – + 2µA 1.25V – TMR GND 4356mp12 BD 4356mp12fc 8 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 OPERATION Some power systems must cope with high voltage surges The potential at the TMR pin starts decreasing as soon as of short duration such as those in automobiles. Load cir- the overvoltage condition disappears. When the voltage cuitry must be protected from these transients, yet high at the TMR pin reaches 0.5V the GATE pin begins rising, availability systems must continue operating during these turning on the MOSFET. The FLT pin will then go to a high events. impedance state. The LT4356 is an overvoltage protection regulator that The fault timer allows the load to continue function- drives an external N-channel MOSFET as the pass transis- ing during short transient events while protecting the tor. It operates from a wide supply voltage range of 4V to MOSFET from being damaged by a long period of supply 80V. It can also be pulled below ground potential by up overvoltage, such as a load dump in automobiles. The to 60V without damage. The low power supply require- timer period varies with the voltage across the MOSFET. A ment of 4V allows it to operate even during cold cranking higher voltage corresponds to a shorter fault timer period, conditions in automotive applications. The internal charge ensuring the MOSFET operates within its safe operating pump turns on the N-channel MOSFET to supply current area (SOA). to the loads with very little power loss. Two MOSFETs can The LT4356 senses an overcurrent condition by monitor- be connected back to back to replace an inline Schottky ing the voltage across an optional sense resistor placed diode for reverse input protection. This improves the effi- between the V and SNS pins. An active current limit CC ciency and increases the available supply voltage level to circuit (IA) controls the GATE pin to limit the sense volt- the load circuitry during cold crank. age to 50mV. A current is also generated to start charging Normally, the pass transistor is fully on, powering the up the TMR pin. This current is about 5 times the current loads with very little voltage drop. When the supply volt- generated during an overvoltage event. The FLT pin pulls age surges too high, the voltage amplifier (VA) controls low when the voltage at the TMR pin reaches 1.25V and the gate of the MOSFET and regulates the voltage at the the MOSFET is turned off when it reaches 1.35V. source pin to a level that is set by the external resistive An auxiliary amplifier is provided with the negative input divider from the OUT pin to ground and the internal 1.25V connected to an internal 1.25V reference. The output pull- reference. A current source starts charging up the capaci- down device is capable of sinking up to 2mA of current tor connected at the TMR pin to ground. If the voltage allowing it to drive an LED or opto coupler. This amplifier at the TMR pin, V , reaches 1.25V, the FLT pin pulls TMR can be configured as a linear regulator controller driving low to indicate impending turn-off due to the overvoltage an external PNP transistor or a comparator function to condition. The pass transistor stays on until the TMR pin monitor voltages. reaches 1.35V, at which point the GATE pin pulls low turn- ing off the MOSFET. A shutdown pin turns off the pass transistor and reduces the supply current to less than 7µA for the LT4356-1. The supply current drops down to 60µA while keeping the internal reference and the auxiliary amplifier active for the LT4356-2 version during shutdown. 4356mp12fc 9 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 APPLICATIONS INFORMATION The LT4356 can limit the voltage and current to the load Overcurrent Fault circuitry during supply transients or overcurrent events. The LT4356 features an adjustable current limit that pro- The total fault timer period should be set to ride through tects against short circuits or excessive load current. short overvoltage transients while not causing damage During an overcurrent event, the GATE pin is regulated to to the pass transistor. The selection of this N-channel limit the current sense voltage across the V and SNS CC MOSFET pass transistor is critical for this application. pins to 50mV. It must stay on and provide a low impedance path from the input supply to the load during normal operation and An overcurrent fault occurs when the current limit cir- then dissipate power during overvoltage or overcurrent cuitry has been engaged for longer than the time-out delay conditions. set by the timer capacitor. The GATE pin is then immedi- ately pulled low by a 10mA current to GND turning off the The following sections describe the overcurrent and the MOSFET. After the fault condition has disappeared and a overvoltage faults, and the selection of the timer capacitor cooldown period has transpired, the GATE pin is allowed value based on the required warning time. The selection of to pull back up and turn on the pass transistor. the N-channel MOSFET pass transistor is discussed next. Auxiliary amplifier, reverse input, and the shutdown func- Fault Timer tions are covered after the MOSFET selection. External The LT4356 includes an adjustable fault timer pin. component selection is discussed in detail in the Design Connecting a capacitor from the TMR pin to ground sets Example section. the delay timer period before the MOSFET is turned off. Overvoltage Fault The same capacitor also sets the cooldown period before the MOSFET is allowed to turn back on after the fault The LT4356 limits the voltage at the OUT pin during an condition has disappeared. overvoltage situation. An internal voltage amplifier regu- lates the GATE pin voltage to maintain a 1.25V threshold at Once a fault condition, either overvoltage or overcurrent, the FB pin. During this period of time, the power MOSFET is detected, a current source charges up the TMR pin. is still on and continues to supply current to the load. This The current level varies depending on the voltage drop allows uninterrupted operation during short overvoltage across the drain and source terminals of the power transient events. MOSFET(VDS), which is typically from the VCC pin to the OUT pin. This scheme takes better advantage of the When the voltage regulation loop is engaged for longer available Safe Operating Area (SOA) of the MOSFET than than the time-out period, set by the timer capacitor con- would a fixed timer current. The timer function operates nected from the TMR pin to ground, an overvoltage fault down to V = 5V across the whole temperature range. CC is detected. The GATE pin is pulled down to the OUT pin by a 150mA current. After the fault condition has disap- peared and a cooldown period has transpired, the GATE pin starts to pull high again. This prevents the power MOSFET from being damaged during a long period of overvoltage, such as during load dump in automobiles. 4356mp12fc 10 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 APPLICATIONS INFORMATION Fault Timer Current When the voltage at the TMR pin, V , reaches the 1.25V TMR threshold, the FLT pin pulls low to indicate the detection The timer current starts at around 2µA with 0.5V or less of a fault condition and provide warning to the load of of V , increasing linearly to 50µA with 75V of V dur- DS DS the impending power loss. In the case of an overvoltage ing an overvoltage fault (Figure 1). During an overcurrent fault, the timer current then switches to a fixed 5µA. The fault, it starts at 4µA with 0.5V or less of V but increases DS interval between FLT asserting low and the MOSFET turn- to 260µA with 80V across the MOSFET (Figure 2). This ing off is given by: arrangement allows the pass transistor to turn off faster during an overcurrent event, since more power C • 100mV t = TMR is dissipated during this condition. Refer to the Typical WARNING 5µA Performance Characteristics section for the timer cur- rent at different V in both overvoltage and overcurrent DS events. VTMR(V) ITMR = 5µA ITMR = 5µA 1.35 1.25 VDS = 75V (ITMR = 50µA) VDS = 10V (ITMR = 8µA) 0.50 TIME tFLT tWARNING = 15ms/µF = 20ms/µF tFLT = 93.75ms/µF tWARNING = 20ms/µF TOTAL FAULT TIMER = tFLT + tWARNING 4356mp12 F01 Figure 1. Overvoltage Fault Timer Current VTMR(V) 1.35 1.25 VDS = 80V (ITMR = 260µA) VDS = 10V (ITMR = 35µA) 0.50 TIME tWARNING tFLT = 0.38ms/µF = 2.88ms/µF tFLT = 21.43ms/µF tWARNING TOTAL FAULT TIMER = tFLT + tWARNING = 2.86ms/µF 4356mp12 F02 Figure 2. Overcurrent Fault Timer Current 4356mp12fc 11 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 APPLICATIONS INFORMATION This fixed early warning period allows the systems to voltage N-channel MOSFETs. For systems with V less CC perform necessary backup or house-keeping functions than 8V, a logic level MOSFET is required since the gate before the power supply is cut off. After V crosses the drive can be as low as 4.5V. TMR 1.35V threshold, the pass transistor turns off immediately. The SOA of the MOSFET must encompass all fault condi- Note that during an overcurrent event, the timer current is tions. In normal operation the pass transistor is fully on, not reduced to 5µA after V has reached 1.25V thresh- TMR dissipating very little power. But during either overvoltage old, since it would lengthen the overall fault timer period or overcurrent faults, the GATE pin is servoed to regu- and cause more stress on the power MOSFET. late either the output voltage or the current through the As soon as the fault condition has disappeared, a 2µA MOSFET. Large current and high voltage drop across the current starts to discharge the timer capacitor to ground. MOSFET can coexist in these cases. The SOA curves of When VTMR reaches the 0.5V threshold, the internal the MOSFET must be considered carefully along with the charge pump starts to pull the GATE pin high, turning selection of the fault timer capacitor. on the MOSFET. The TMR pin is then actively regulated to 0.5V until the next fault condition appears. The total Transient Stress in the MOSFET cooldown timer period is given by: During an overvoltage event, the LT4356 drives a series C • 0.85V pass MOSFET to regulate the output voltage at an accept- t = TMR COOL 2µA able level. The load circuitry may continue operating throughout this interval, but only at the expense of dis- MOSFET Selection sipation in the MOSFET pass device. MOSFET dissipation or stress is a function of the input voltage waveform, The LT4356 drives an N-channel MOSFET to conduct the regulation voltage and load current. The MOSFET must load current. The important features of the MOSFET are be sized to survive this stress. on-resistance R , the maximum drain-source volt- DS(ON) age V(BR)DSS, the threshold voltage, and the SOA. Most transient event specifications use the model shown in Figure 3. The idealized waveform comprises a linear The maximum allowable drain-source voltage must be ramp of rise time t , reaching a peak voltage of V and higher than the supply voltage. If the output is shorted r PK exponentially decaying back to V with a time constant to ground or during an overvoltage event, the full supply IN of t. A common automotive transient specification has voltage will appear across the MOSFET. constants of t = 10µs, V = 80V and t = 1ms. A surge r PK The gate drive for the MOSFET is guaranteed to be more condition known as “load dump” has constants of t = r than 10V and less than 16V for those applications with V CC 5ms, V = 60V and t = 200ms. PK higher than 8V. This allows the use of standard threshold VPK τ VIN tr 4356mp12 F03 Figure 3. Prototypical Transient Waveform 4356mp12fc 12 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 APPLICATIONS INFORMATION MOSFET stress is the result of power dissipated within VPK the device. For long duration surges of 100ms or more, stress is increasingly dominated by heat transfer; this is τ a matter of device packaging and mounting, and heatsink thermal mass. This is analyzed by simulation, using the VREG MOSFET thermal model. VIN tr For short duration transients of less than 100ms, MOSFET 4356mp12 F04 survival is increasingly a matter of safe operating area Figure 4. Safe Operating Area Required to Survive Prototypical (SOA), an intrinsic property of the MOSFET. SOA quanti- Transient Waveform fies the time required at any given condition of V and DS ID to raise the junction temperature of the MOSFET to Typically VREG ≈ VIN and t >> tr simplifying the above to its rated maximum. MOSFET SOA is expressed in units of watt-squared-seconds (P2t). This figure is essentially P2t = 1 I 2(V –V )2t (W2s) LOAD PK REG constant for intervals of less than 100ms for any given 2 device type, and rises to infinity under DC operating For the transient conditions of V = 80V, V = 12V, V conditions. Destruction mechanisms other than bulk die PK IN REG = 16V, t = 10µs and t = 1ms, and a load current of 3A, P2t temperature distort the lines of an accurately drawn SOA r is 18.4W2s—easily handled by a MOSFET in a D-pak pack- graph so that P2t is not the same for all combinations age. The P2t of other transient waveshapes is evaluated by of I and V . In particular P2t tends to degrade as V D DS DS integrating the square of MOSFET power versus time. approaches the maximum rating, rendering some devices useless for absorbing energy above a certain voltage. Calculating Short-Circuit Stress Calculating Transient Stress SOA stress must also be calculated for short-circuit con- ditions. Short-circuit P2t is given by: To select a MOSFET suitable for any given application, the SOA stress must be calculated for each input transient P2t = (V • ΔV /R )2 • t (W2s) IN SNS SNS TMR which shall not interrupt operation. It is then a simple where, ΔV is the SENSE pin threshold, and t is the SNS TMR matter to chose a device which has adequate SOA to sur- overcurrent timer interval. vive the maximum calculated stress. P2t for a prototypical transient waveform is calculated as follows (Figure 4). For VIN = 14.7V, VSNS = 50mV, RSNS = 12mΩ and CTMR = 100nF, P2t is 6.6W2s—less than the transient SOA Let calculated in the previous example. Nevertheless, to a = V – V account for circuit tolerances this figure should be dou- REG IN b = V – V bled to 13.2W2s. PK IN (V = Nominal Input Voltage) IN Limiting Inrush Current and GATE Pin Compensation Then The LT4356 limits the inrush current to any load capaci- 1 (b–a)3 1  b  tance by controlling the GATE pin voltage slew rate. An P2t = I 2 t + t2a2ln +3a2+b2−4ab LOAD 3 r b 2  a  external capacitor can be connected from GATE to ground   to slow down the inrush current further at the expense of slower turn-off time. The gate capacitor is set at: I GATE(UP) C1 = •C L I INRUSH 4356mp12fc 13 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 APPLICATIONS INFORMATION The LT4356 does not need extra compensation compo- The amplifier can also be configured as a low dropout nents at the GATE pin for stability during an overvoltage or linear regulator controller. With an external PNP transistor, overcurrent event. With transient input voltage step faster such as 2N2905A, it can supply up to 100mA of current than 5V/µs, a gate capacitor, C1, to ground is needed to with only a few hundred mV of dropout voltage. Current prevent self enhancement of the N-channel MOSFET. limit can be easily included by adding two diodes and one resistor (Figure 6). The extra gate capacitance slows down the turn-off time during fault conditions and may allow excessive current RLIM 2N2905A OR during an output short event. An extra resistor, R1, in *4.7Ω BCP53 2.5V OUTPUT INPUT ≈ 150mA MAX series with the gate capacitor can improve the turn-off 10µF time. A diode, D1, should be placed across R1 with the R6 * OPTIONAL FOR cathode connected to C1 as shown in Figure 5. 100k D1* CURRENT LIMIT BAV99 R4+R5 11 VOUT=1.25 R5 R4 Q1 D1 LT4356S AOIUNT+ 12 249k 47nF ILIM≈R0L.I7M IN4148W 4356 F06 R5 R3 249k R1 C1 Figure 6. Auxiliary LDO Output with Optional Current Limit GATE LT4356S Reverse Input Protection 4356mp F05 A blocking diode is commonly employed when reverse input potential is possible, such as in automotive applica- Figure 5 tions. This diode causes extra power loss, generates heat, Auxiliary Amplifier and reduces the available supply voltage range. During cold crank, the extra voltage drop across the diode is An uncommitted amplifier is included in the LT4356 to particularly undesirable. provide flexibility in the system design. With the nega- tive input connected internally to the 1.25V reference, the The LT4356 is designed to withstand reverse voltage amplifier can be connected as a level detect compara- without damage to itself or the load. The VCC, SNS, and tor with external hysteresis. The open collector output SHDN pins can withstand up to 60V of DC voltage below pin, A , is capable of driving an opto or LED. It can the GND potential. Back-to-back MOSFETs must be used OUT also interface with the system via a pull-up resistor to a to eliminate the current path through their body diodes supply voltage up to 80V. Another use is to implement (Figure 7). Figure 8 shows the approach with a P-channel undervoltage lockout, as shown in the typical application MOSFET in place of Q2. “Overvoltage Regulator with Undervoltage Lockout.” In shutdown, the auxiliary amplifier turns off in the LT4356-1 but continues operating in the LT4356-2. 4356mp12fc 14 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 APPLICATIONS INFORMATION RSNS Q2 Q1 Shutdown VIN 10mΩ IRLR2908 IRLR2908 VOUT 12V 12V, 3A The LT4356 can be shut down to a low current mode CLAMPED D2* when the voltage at the SHDN pin goes below the shut- SMAJ58CA Q3 R4 R5 R3 AT 16V 2N3904 10Ω 1M 10Ω down threshold of 0.6V. The quiescent current drops to 7µA for the LT4356-1 and 60µA for the LT4356-2 which R1 59k leaves the auxiliary amplifier on. D1 R7 1N4148 10k The SHDN pin can be pulled up to V or below GND by CC 7 5 4 up to 60V without damaging the pin. Leaving the pin open SNS GATE OUT 8 2 VCC FB allows an internal current source to pull it up and turn R2 on the part while clamping the pin to 2.5V. The leakage 4.99k current at the pin should be limited to no more than 1µA LT4356S if no pull-up device is used to help turn it on. 9 SHDN 14 AOUT FLT 10 Supply Transient Protection 16 IN+ GND TMR EN 11 The LT4356 is guaranteed to be safe from damage with 12 1 4356mp12 F07 *DIODES INC. CTMR supply voltages up to 100V. Nevertheless, voltage tran- 0.1µF sients above 100V may cause permanent damage. During a short-circuit condition, the large change in current flow- Figure 7. Overvoltage Regulator with N-channel MOSFET ing through power supply traces and associated wiring Reverse Input Protection can cause inductive voltage transients which could exceed 100V. To minimize the voltage transients, the power trace RSNS Q2 Q1 VIN 10mΩ Si4435 IRLR2908 VOUT parasitic inductance should be minimized by using wide 12V D1 12V, 3A traces. A small surge suppressor, D2, in Figure 9, at the D2* 1N5245 CLAMPED SMAJ58CA 15V AT 16V input will clamp the voltage spikes. R3 R6 10Ω R1 10k 59k RSNS Q1 7 5 4 10mΩ IRLR2908 VIN SNS GATE OUT D2 CL* 8 VCC FB 2 SMAJ58A 22µF R2 R3 R1 4.99k 10Ω 59k 7 5 4 LT4356S 9 SHDN 8 VCC SNS GATE OUT 2 14 AOUT FLT 10 38R34k 9 SHDN FB R2 VCC 16 IN+ EN 11 16 IN+ LT4356S 4.99k DC-DC GND TMR CONVERTER R5 *DIODES INC. 12 1 C0.T1MµRF 4356mp12 F08 100k EN 11 SHDN GND 14 10 UNDERVOLTAGE AOUT GND TMR FLT FAULT 12 1 4356mp12 F09 *SANYO 25CE22GA Figure 8. Overvoltage Regulator with P-channel MOSFET CTMR 47nF Reverse Input Protection Figure 9. Overvoltage Regulator with Low-Battery Detection 4356mp12fc 15 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 APPLICATIONS INFORMATION A total bulk capacitance of at least 22µF low ESR electro- Next calculate the sense resistor, R , value: SNS lytic is required close to the source pin of MOSFET Q1. In 50mV 50mV addition, the bulk capacitance should be at least 10 times R = = = 10mΩ SNS I 5A larger than the total ceramic bypassing capacitor on the LIM input of the DC/DC converter. C is then chosen for 1ms of early warning time: TMR Layout Considerations 1ms • 5µA C = = 50nF TMR To achieve accurate current sensing, Kelvin connection 100mV to the current sense resistor (R in Figure 9) is recom- SNS The closest standard value for C is 47nF. TMR mended. The minimum trace width for 1oz copper foil is 0.02" per amp to ensure the trace stays at a reasonable Finally, calculate R4 and R5 for the 6V low battery thresh- temperature. 0.03" per amp or wider is recommended. old detection: Note that 1oz copper exhibits a sheet resistance of about 1.25V • (R4 + R5) 530µΩ/square. Small resistances can cause large errors 6V = R5 in high current applications. Noise immunity will be improved significantly by locating resistive dividers close Choose 100k for R5. to the pins with short V and GND traces. CC (6V – 1.25V) • R5 R4 = = 380k Design Example 1.25V As a design example, take an application with the follow- Select 383k for R4. ing specifications: V = 8V to 14V DC with transient up CC The pass transistor, Q1, should be chosen to withstand to 80V, V ≤ 16V, current limit (I ) at 5A, low battery OUT LIM the output short condition with V = 14V. detection at 6V, and 1ms of overvoltage early warning CC (Figure 9). The total overcurrent fault time is: First, calculate the resistive divider value to limit VOUT to 47nF • 0.85V t = = 0.878ms 16V during an overvoltage event: OC 45.5µA 1.25V • (R1 + R2) The power dissipation on Q1 equals to: V = =16V REG R2 14V • 50mV P = = 70W Set the current through R1 and R2 during the overvoltage 10mΩ condition to 250µA. These conditions are well within the Safe Operating Area 1.25V of IRLR2908. R2 = = 5k 250µA Choose 4.99k for R2. (16V – 1.25V) • R2 R1 = = 58.88k 1.25V The closest standard value for R1 is 59k. 4356mp12fc 16 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 TYPICAL APPLICATIONS Wide Input Range 5V to 28V Hot Swap with Undervoltage Lockout RSNS Q1 20mΩ SUD50N03-10 VIN VOUT 100µF R6 R3 118k 10Ω C1 8 7 5 4 47nF VCC SNS GATE OUT 9 2 SHDN FB 14 AOUT 16 IN+ LT4356S-1 R7 49.9k 10 FLT 11 EN GND TMR 12 1 4356mp12 TA02 CTMR 1µF 24V Overvoltage Regulator Withstands 150V at V IN Q1 VIN IRF640 VOUT 24V CLAMPED AT 32V R9 1k R3 1W 10Ω R1 7 5 4 118k SNS GATE OUT 8 2 VCC FB D2* R2 SMAT70A 4.99k 9 LT4356S SHDN 10 FLT 11 EN GND TMR 12 1 4356mp12 TA03 *DIODES INC. CTMR 0.1µF 4356mp12fc 17 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 TYPICAL APPLICATIONS Overvoltage Regulator with Undervoltage Lockout RSNS Q1 20mΩ IRLR2908 VIN VCOLAUTMPED AT 16V D2* R3 SMAJ58A R6 R4 280k 1M 10Ω R1 8 7 5 4 59k VCC SNS GATE OUT R5 9 2 SHDN FB 1M 14 AOUT R2 16 4.99k IN+ LT4356S-2 R7 100k 10 FLT 11 EN *DIODES INC. GND TMR 12 1 4356mp12 TA04 CTMR 0.1µF Overvoltage Regulator with Low Battery Detection and Output Keep Alive During Shutdown 1k 0.5W RSNS Q1 VIN 10mΩ IRLR2908 1V2OVU,T 4A 12V CLAMPED AT 16V D2* SMAJ58A R3 10Ω D1 Q2 1N4746A R4 VN2222 18V 402k 7 5 4 R1 1W SNS GATE OUT 294k 8 VCC FB 2 R2 VDD 24.9k R6 LT4356S 47k 16 IN+ AOUT 14 LBO R5 9 10 105k SHDN FLT 11 EN GND TMR *DIODES INC. 12 1 4356mp12 TA05 CTMR 0.1µF 4356mp12fc 18 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 TYPICAL APPLICATIONS 2.5A, 48V Hot Swap with Overvoltage Output Regulation at 72V and UV Shutdown at 35V RSNS Q1 VIN 15mΩ FDB3632 VOUT 48V 48V R4 R6 2.5A D2* SMAT70A R3 140k 100k 10Ω CL 300µF C1 6.8nF D1 8 7 5 4 1N4714 VCC SNS GATE OUT R7 BV = 33V9 IN+ 16 1M SHDN R5 R8 4.02k R1 47k 226k LT4356S 2 FB R2 10 4.02k FLT 11 14 EN AOUT PWRGD GND TMR *DIODES INC. 12 1 4356mp12 TA06 CTMR 0.1µF 2.5A, 28V Hot Swap with Overvoltage Output Regulation at 36V and UV Shutdown at 15V RSNS Q1 VIN 15mΩ FDB3632 VOUT 28V 28V R4 R6 2.5A D2* SMAT70A R3 113k 27k 10Ω CL 300µF C1 6.8nF D1 8 7 5 4 1N4700 VCC SNS GATE OUT R7 BV = 13V9 IN+ 16 1M SHDN R5 R8 4.02k R1 47k 110k LT4356S 2 FB R2 10 4.02k FLT 11 14 EN AOUT PWRGD GND TMR *DIODES INC. 12 1 4356mp12 TA07 CTMR 0.1µF 4356mp12fc 19 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 TYPICAL APPLICATIONS Overvoltage Regulator with Reverse Input Protection Up to –80V Q2 RSNS Q1 VIN IRLR2908 10mΩ IRLR2908 VOUT 12V 12V, 3A CLAMPED D2* R4 SMAJ58CA R3 AT 16V Q3 10Ω R5 10Ω 2N3904 1M 8 7 5 4 R1 D1 R7 VCC SNS GATE OUT 2 59k 1N4148 10k FB R2 D3** 4.99k IN4148 LT4356S 9 SHDN 14 10 AOUT FLT 16 IN+ GND TMR EN 11 * DIODES INC. 12 1 4356mp12 TA08 ** OPTIONAL COMPONENT FOR CTMR REDUCED STANDBY CURRENT 0.1µF 4356mp12fc 20 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 PACKAGE DESCRIPTION Please refer to http://www.linear.com/product/LT4356MP-1#packaging for the most recent package drawings. MS Package 10-Lead Plastic MSOP (Reference LTC DWG # 05-08-1661) 0.889 ± 0.127 (.035 ± .005) 5.23 3.20 – 3.45 (.206) (.126 – .136) MIN 3.00 ± 0.102 0.305 ± 0.038 0.50 (.118 ± .004) 0.497 ± 0.076 (.0120 ± .0015) (.0197) (NOTE 3) (.0196 ± .003) 10 9 8 76 TYP BSC REF RECOMMENDED SOLDER PAD LAYOUT 3.00 ± 0.102 4.90 ± 0.152 DETAIL “A” (.193 ± .006) (.118 ± .004) 0.254 (NOTE 4) (.010) 0° – 6° TYP GAUGE PLANE 1 2 3 4 5 0.53 ± 0.152 (.021 ± .006) 1.10 0.86 (.043) (.034) DETAIL “A” MAX REF 0.18 (.007) SEATING PLANE 0.17 – 0.27 0.1016 ± 0.0508 (.007 – .011) (.004 ± .002) 0.50 TYP (.0197) MSOP (MS) 0307 REV E NOTE: BSC 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") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 4356mp12fc 21 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 PACKAGE DESCRIPTION Please refer to http://www.linear.com/product/LT4356MP-1#packaging for the most recent package drawings. S Package 16-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) .386 – .394 .045 ±.005 (9.804 – 10.008) .050 BSC NOTE 3 16 15 14 13 12 11 10 9 N N .245 MIN .160 ±.005 .150 – .157 .228 – .244 (3.810 – 3.988) (5.791 – 6.197) NOTE 3 1 2 3 N/2 N/2 .030 ±.005 TYP RECOMMENDED SOLDER PAD LAYOUT 1 2 3 4 5 6 7 8 .010 – .020 × 45° .053 – .069 (0.254 – 0.508) (1.346 – 1.752) .004 – .010 .008 – .010 (0.101 – 0.254) (0.203 – 0.254) 0° – 8° TYP .014 – .019 .050 .016 – .050 (0.355 – 0.483) (1.270) (0.406 – 1.270) TYP BSC S16 0502 NOTE: INCHES 1. DIMENSIONS IN (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) 4356mp12fc 22 For more information www.linear.com/LT4356MP-1

LT4356MP-1/LT4356MP-2 REVISION HISTORY (Revision history begins at Rev A) REV DATE DESCRIPTION PAGE NUMBER A 05/10 Revised Features and Description 1 Added parameters to V in the Electrical Characteristics section 3 OL Rearranged Typical Performance Characteristics 4 Revised Pin Functions section 7 Made minor text edits to the Operation section 9 Replaced Figure 6 and text edits in the Applications Information section 13-20 B 01/12 Revised Max value for I current at V = 12V 3 GATE(UP) CC Correct part number 10, 14 C 09/17 Updated TMR pin function with minimum recommended capacitance 7 4356mp12fc Information furnished by Linear Technology Corporation is believed to be accurate and reliable. 23 However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconFnoerc tmiono roef iitns fcoirrcmuitast iaosn d ewscwriwbe.dli nheeraeri.nc woimll n/LotT i4nf3ri5n6geM oPn -e1xisting patent rights.

LT4356MP-1/LT4356MP-2 TYPICAL APPLICATION Overvoltage Regulator with Linear Regulator Up to 100mA Q2 2N2905A 2.5V, 100mA C5 RSNS Q1 10µF VIN 10mΩ IRLR2908 VOUT 12V 12V, 3A D2* CLAMPED AT 16V SMAJ58A R3 10Ω R1 7 5 4 59k R6 SNS GATE OUT 100k 8 2 VCC FB R2 4.99k R4 C3 LT4356S 249k 47nF 14 AOUT IN+ 16 R5 9 10 SHDN FLT 249k 11 EN GND TMR *DIODES INC. 12 1 4356mp12 TA09 CTMR 0.1µF RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1641-1/LT1641-2 Positive High Voltage Hot Swap Controllers Active Current Limiting, Supplies From 9V to 80V LTC®1696 Overvoltage Protection Controller ThinSOT™ Package, 2.7V to 28V LTC1735 High Efficiency Synchronous Step-Down Output Fault Protection, 16-Pin SSOP Switching Regulator LTC1778 No R ™ Wide Input Range Synchronous Up to 97% Efficiency, 4V ≤ V ≤ 36V, 0.8V ≤ V ≤ (0.9)(V ), SENSE IN OUT IN Step-Down Controller I Up to 20A OUT LTC2909 Triple/Dual Inputs UV/OV Negative Monitor Pin Selectable Input Polarity Allows Negative and OV Monitoring LTC2912/LTC2913 Single/Dual UV/OV Voltage Monitor Ads UV and OV Trip Values, ±1.5% Threshold Accuracy LTC2914 Quad UV/OV Monitor For Positive and Negative Supplies LTC3727/LTC3727-1 2-Phase, Dual, Synchronous Controller 4V ≤ V ≤ 36V, 0.8V ≤ V ≤ 14V IN OUT LTC3827/LTC3827-1 Low I , Dual, Synchronous Controller 4V ≤ V ≤ 36V, 0.8V ≤ V ≤ 10V, 80µA Quiescent Current Q IN OUT LTC3835/LTC3835-1 Low I , Synchronous Step-Down Controller Single Channel LTC3827/LTC3827-1 Q LT3845 Low I , Synchronous Step-Down Controller 4V ≤ V ≤ 60V, 1.23V ≤ V ≤ 36V, 120µA Quiescent Current Q IN OUT LTC3850 Dual, 550kHz, 2-Phase Sychronous Step-Down Dual 180° Phased Controllers, V 4V to 24V, 97% Duty Cycle, IN Controller 4mm × 4mm QFN-28, SSOP-28 Packages LT4256 Positive 48V Hot Swap Controller with Foldback Current Limiting, Open-Circuit and Overcurrent Fault Output, Open-Circuit Detect Up to 80V Supply LTC4260 Positive High Voltage Hot Swap Controller with Wide Operating Range 8.5V to 80V ADC and I2C LTC4352 Ideal MOSFET ORing Diode External N-channel MOSFETs Replace ORing Diodes, 0V to 18V Operation LTC4354 Negative Voltage Diode-OR Controller Controls Two N-channel MOSFETs, 1µs Turn-Off, 80V Operation LTC4355 Positive Voltage Diode-OR Controller Controls Two N-channel MOSFETs, 0.5µs Turn-Off, 80V Operation 4356mp12fc 24 LT 0917 REV C • PRINTED IN USA www.linear.com/LT4356MP-1 For more information www.linear.com/LT4356MP-1 © LINEAR TECHNOLOGY CORPORATION 2009

Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: A nalog Devices Inc.: LT4356MPS-1#TR LT4356MPS-2#PBF LT4356MPMS-1#TR LT4356MPS-1#TRPBF LT4356MPMS-1 LT4356MPS- 2#TR LT4356MPS-2#TRPBF LT4356MPS-1 LT4356MPS-2 LT4356MPS-1#PBF LT4356MPMS-1#TRPBF LT4356MPMS-1#PBF