LTC4252B-1/LTC4252B-2 LTC4252C-1/LTC4252C-2 Negative Voltage Hot Swap Controllers FEATURES DESCRIPTION TM n Allows Safe Board Insertion and Removal from a The LTC 4252 negative voltage Hot Swap controller Live 48V Backplane allows a board to be safely inserted and removed from a n Floating Topology Permits Very High Voltage Operation live backplane. Output current is controlled by three stages n Current Limit With Circuit Breaker Timer of current limiting: a timed circuit breaker, active current n Fast Response Time Limits Peak Fault Current limiting and a fast feedforward path that limits peak current n Programmable Soft-Start Current Limit under worst-case catastrophic fault conditions. n Programmable Timer with Drain Voltage Adjustable undervoltage and overvoltage detectors dis- Accelerated Response connect the load whenever the input supply exceeds the n 1% Undervoltage/Overvoltage Threshold (LTC4252C) desired operating range. The LTC4252s supply input is n Improved Ruggedness Shunt Regulator shunt regulated, allowing safe operation with very high Adjustable Undervoltage/Overvoltage Protection supply voltages. A multifunction timer delays initial start- LTC4252B-1/LTC4252C-1: Latch Off After Fault up and controls the circuit breakers response time. The LTC4252B-2/LTC4252C-2: Automatic Retry After Fault circuit breakers response time is accelerated by sensing Available in 8-Pin and 10-Pin MSOP Packages excessive MOSFET drain voltage, keeping the MOSFET within its safe operating area (SOA). An adjustable soft- APPLICATIONS start circuit controls MOSFET inrush current at start-up. n Hot Board Insertion The LTC4252-2 provides automatic retry after a fault. The n Electronic Circuit Breaker LTC4252C-1/LTC4252C-2 feature tight 1% undervoltage/ n 48V Distributed Power Systems overvoltage threshold accuracy. The LTC4252 is available n Negative Power Supply Control in either an 8-pin or 10-pin MSOP. n Central Office Switching n High Availability Servers The LTC4252B and LTC4252C improve the ruggedness n ATCA of the shunt regulator in the LTC4252 and LTC4252A. L, LT, LTC, 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. TYPICAL APPLICATION Start-Up Behavior 48V/2.5A Hot Swap Controller 48RTN R + IN GATE C L 3 1.8k IN SERIES 5V/DIV 100F 1/4W EACH C R3 LOAD D IN IN 48RTN ** 1F 5.1k DDZ13B (SHORT PIN) V SENSE R1 IN EN 2.5A/DIV 402k LTC4252B-1 V OUT * 1% OV PWRGD R 1M D UV DRAIN V OUT R2 Q1 20V/DIV TIMER GATE 32.4k IRF530S C 1% T SS V SENSE EE 0.33F R R C S C1 C 10 0.02 SS 10nF 68nF C C PWRGD 18nF 10V/DIV 4252B12 TA01 48V 1ms/DIV 4252B12 TA01a * M0C207 RECOMMENDED FOR HARSH ENVIRONMENTS **DIODES, INC 4252b12f 1LTC4252B-1/LTC4252B-2 LTC4252C-1/LTC4252C-2 ABSOLUTE MAXIMUM RATINGS All Voltages Referred to V (Note 1) EE Current into V (100s Pulse) .............................100mA Operating Temperature Range IN V , DRAIN Pin Minimum Voltage ........................ 0.3V LTC4252BC-1/LTC4252BC-2 IN Input/Output Pins LTC4252CC-1/LTC4252CC-2 .................... 0C to 70C (Except SENSE and DRAIN) Voltage .......... 0.3V to 16V LTC4252BI-1/LTC4252BI-2 SENSE Pin Voltage .................................... 0.6V to 16V LTC4252CI-1/LTC4252CI-2 ................. 40C to 85C Current Out of SENSE Pin (20s Pulse) .......... 200mA Storage Temperature Range .................. 65C to 150C Current into DRAIN Pin (100s Pulse) ...................20mA Lead Temperature (Soldering, 10 sec) ...................300C Maximum Junction Temperature .......................... 125C PIN CONFIGURATION TOP VIEW TOP VIEW V 1 10 TIMER IN V 1 8 TIMER IN PWRGD 2 9 UV SS 2 7 UV/OV SS 3 8 OV SENSE 3 6 DRAIN SENSE 4 7 DRAIN V 4 5 GATE EE V 5 6 GATE EE MS8 PACKAGE MS PACKAGE 8-LEAD PLASTIC MSOP 10-LEAD PLASTIC MSOP T = 125C, = 160C/W JMAX JA T = 125C, = 160C/W JMAX JA ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC4252BCMS8-1 PBF LTC4252BCMS8-1 TRPBF LTGDX 8-Lead Plastic MSOP 0C to 70C LTC4252BCMS8-2 PBF LTC4252BCMS8-2 TRPBF LTGDZ 8-Lead Plastic MSOP 0C to 70C LTC4252BIMS8-1 PBF LTC4252BIMS8-1 TRPBF LTGDX 8-Lead Plastic MSOP 40C to 85C LTC4252BIMS8-2 PBF LTC4252BIMS8-2 TRPBF LTGDZ 8-Lead Plastic MSOP 40C to 85C LTC4252BCMS-1 PBF LTC4252BCMS-1 TRPBF LTGDY 10-Lead Plastic MSOP 0C to 70C LTC4252BCMS-2 PBF LTC4252BCMS-2 TRPBF LTGFB 10-Lead Plastic MSOP 0C to 70C LTC4252BIMS-1 PBF LTC4252BIMS-1 TRPBF LTGDY 10-Lead Plastic MSOP 40C to 85C LTC4252BIMS-2 PBF LTC4252BIMS-2 TRPBF LTGFB 10-Lead Plastic MSOP 40C to 85C LTC4252CCMS-1 PBF LTC4252CCMS-1 TRPBF LTGFC 10-Lead Plastic MSOP 0C to 70C LTC4252CCMS-2 PBF LTC4252CCMS-2 TRPBF LTGFD 10-Lead Plastic MSOP 0C to 70C LTC4252CIMS-1 PBF LTC4252CIMS-1 TRPBF LTGFC 10-Lead Plastic MSOP 40C to 85C LTC4252CIMS-2 PBF LTC4252CIMS-2 TRPBF LTGFD 10-Lead Plastic MSOP 40C to 85C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. 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