LTC4253/LTC4253A 48V Hot Swap Controllers with Sequencer FEATURES DESCRIPTION n Allows Safe Board Insertion and Removal from a The LTC 4253/LTC4253A negative voltage Hot Swap Live 48V Backplane controllers allow a board to be safely inserted and removed n Floating Topology Permits Very High Voltage from a live backplane. Output current is controlled by three Operation stages of current-limiting: a timed circuit breaker, active n Adjustable Analog Current Limit with Breaker Timer current limiting and a fast feedforward path that limits Ideal for Two Battery Feeds peak current under worst-case catastrophic fault condi- n Fast Response Time Limits Peak Fault Current tions. The LTC4253/LTC4253A latch off after a circuit fault. n Adjustable Undervoltage/Overvoltage Protection Adjustable undervoltage and overvoltage detectors dis- with 1% Threshold Accuracy (LTC4253A) connect the load whenever the input supply exceeds the n Three Sequenced Power Good Outputs desired operating range. The LTC4253/LTC4253As supply n Adjustable Soft-Start Current Limit input is shunt-regulated, allowing safe operation with very n Adjustable Timer with Drain Voltage Accelerated high supply voltages. A multifunction timer delays initial Response start-up and controls the circuit breakers response time. n Latchoff After Fault The circuit breakers response time can be accelerated n Available in a 16-Pin SSOP Package by sensing excessive MOSFET drain voltage, keeping the MOSFET within its safe operating area (SOA). An adjustable APPLICATIONS soft-start circuit controls MOSFET inrush current at start-up. n 48V Distributed Power Systems Three power good outputs are sequenced by an adjustable n Negative Power Supply Control timer and two ENABLE inputs to enable external power n Central Office Switching modules at start-up or disable them if the circuit breaker n High Availability Servers trips. The LTC4253A features tight 1% undervoltage/ n Disk Arrays overvoltage threshold accuracy. The LTC4253/LTC4253A 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 are available in a 16-pin SSOP. their respective owners. TYPICAL APPLICATION 48V/2.5A Hot Swap Controller 48V RTN Start-Up Behavior 2.5k 15k(1/4W)/6 + V 1F IN LOAD1 100F 48V RTN LOAD2 5.6k 5.6k 5.6k GATE 402k 10V EN2 EN3 V 10nF IN EN LOAD3 1% D IN LTC4253 DDZ13B* EN RESET SS EN 1V UV PWRGD1 4253 TA01 SENSE OV PWRGD2 50mV 32.4k 68nF SS PWRGD3 1% DRAIN 0.1F SQTIMER 1M *DIODES, INC. IRF530S V GATE OUT B3100* MOC207 0.33F 50V 48V A TIMER SENSE RECOMMENDED FOR HARSH ENVIRONMENTS. V 10 EE 4253 TA01b 1ms/DIV 0.02 B3100* 18nF 48V B 425353aff For more information www.linear.com/4253 1LTC4253/LTC4253A ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1), All voltages referred to V EE TOP VIEW Current into V (100s Pulse) .............................100mA IN EN2 1 16 PWRGD3 Current into DRAIN (100s Pulse) .........................20mA PWRGD2 2 15 EN3 V , DRAIN Minimum Voltage ................................0.3V IN PWRGD1 3 14 SQTIMER Input/Output (Except SENSE V 4 13 TIMER IN and DRAIN) Voltage ................................... 0.3V to 16V RESET 5 12 UV SENSE Voltage ........................................... 0.6V to 16V SS 6 11 OV Current Out of SENSE (20s Pulse) .................. 200mA SENSE 7 10 DRAIN Maximum Junction Temperature .......................... 125C V 8 9 GATE EE Operating Temperature Range GN PACKAGE 16-LEAD PLASTIC SSOP LTC4253C ................................................ 0C to 70C T = 125C, = 130C/W JMAX JA LTC4253I .............................................40C to 85C LTC4253AC (OBSOLETE) ......................... 0C to 70C LTC4253AI (OBSOLETE) ......................40C to 85C Storage Temperature Range .................. 65C to 150C Lead Temperature (Soldering, 10 sec) ...................300C ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC4253CGN PBF LTC4253CGN TRPBF 4253 16-Lead Plastic SSOP 0C to 70C LTC4253IGN PBF LTC4253IGN TRPBF 4253I 16-Lead Plastic SSOP 40C to 85C OBSOLETE PACKAGE LTC4253ACGN PBF LTC4253ACGN TRPBF 4253A 16-Lead Plastic SSOP 0C to 70C LTC4253AIGN PBF LTC4253AIGN TRPBF 4253AI 16-Lead Plastic SSOP 40C to 85C Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: