LT4250L/LT4250H Negative 48V Hot Swap Controller FEATURES DESCRIPTION n Allows Safe Board Insertion and Removal from a The LT 4250L/LT4250H are 8-pin, negative 48V Hot Swap Live 48V Backplane controllers that allow a board to be safely inserted and n Circuit Breaker Immunity to Voltage Steps and removed from a live backplane. Inrush current is limited Current Spikes to a programmable value by controlling the gate voltage n Programmable Inrush and Short-Circuit Current of an external N-channel pass transistor. The pass tran- Limits sistor is turned off if the input voltage is less than the n Pin Compatible With LT1640L/LT1640H programmable undervoltage threshold or greater than n Operates from 18V to 80V the overvoltage threshold. A programmable current limit n Programmable Overvoltage Protection protects the system against shorts. After a 500s timeout n Programmable Undervoltage Lockout the current limit activates the electronic circuit breaker. n Power Good Control Output The PWRGD (LT4250L) or PWRGD (LT4250H) signal can n Bell-Core Compatible ON/OFF Threshold be used to directly enable a power module. The LT4250L is designed for modules with a low enable input and the LT4250H for modules with a high enable input. APPLICATIONS The LT4250L/LT4250H are available in 8-pin PDIP and n Central Office Switching SO packages n 48V Distributed Power Systems L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Hot Swap is a n Negative Power Supply Control trademark of Linear Technology Corporation. TYPICAL APPLICATION Voltage Step on Input Supply 48V RTN (SHORT PIN) 48V RTN R4 549k 8 1% V DD 3 V AND UV = EE UV DRAIN 38.5V R5 1 20V/DIV LT4250L PWRGD UV 6.49k 2 RELEASE 1% OV AT 43V R6 OV = V SENSE GATE DRAIN EE 10k I (Q1) D 71V 1% 5A/DIV 4 56 7 R3 1k, 5% * 0.1F R2 C1 10V 4250 TA01b 48V 470nF 10 C2 500s/DIV R1 INPUT 1 25V 5% 15nF 0.02 100V 5% 2 Q1 IRF530 ON/OFF 1 9 + + 48V 5V V V IN OUT 8 INPUT 2 + SENSE C3 + C4 + C5 7 * DIODES INC. SMAT70A 0.1F 100F 100F TRIM THESE COMPONENTS ARE APPLICATION 100V 6 100V 16V SENSE SPECIFIC AND MUST BE SELECTED BASED 4 5 UPON OPERATING CONDITIONS AND DESIRED V V IN OUT PERFORMANCE. SEE APPLICATIONS 4250 TA01a INFORMATION. LUCENT JW050A1-E 4250lhfa 1LT4250L/LT4250H ABSOLUTE MAXIMUM RATINGS (Note 1), All Voltages Referred to V EE Operating Temperature Range Supply Voltage (V V ) ...................... 0.3V to 100V DD EE LT4250LC/LT4250HC ............................... 0C to 70C PWRGD, PWRGD Pins ............................. 0.3V to 100V LT4250LI/LT4250HI .............................. 40C to 85C SENSE, GATE Pins ..................................... 0.3V to 20V Storage Temperature Range ................... 65C to 150C UV, OV Pins ................................................ 0.3V to 60V Lead Temperature (Soldering, 10 sec) .................. 300C DRAIN Pin ................................................... 2V to 100V Maximum Junction Temperature........................... 125C PIN CONFIGURATION TOP VIEW TOP VIEW PWRGD 1 8 V PWRGD 1 8 V DD DD OV 2 7 DRAIN OV 2 7 DRAIN UV 3 6 GATE UV 3 6 GATE V SENSE V 4 5 SENSE 4 5 EE EE N8 PACKAGE S8 PACKAGE N8 PACKAGE S8 PACKAGE 8-LEAD PDIP 8-LEAD PLASTIC SO 8-LEAD PDIP 8-LEAD PLASTIC SO T = 125C, = 120C/W (N8) T = 125C, = 120C/W (N8) JMAX JA JMAX JA T = 125C, = 150C/W (S8) T = 125C, = 150C/W (S8) JMAX JA JMAX JA ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT4250LCN8 PBF LT4250LCN8 TRPBF 4250L 8-Lead PDIP 0C to 70C LT4250LCS8 PBF LT4250LCS8 TRPBF 4250L 8-Lead PLASTIC SO 0C to 70C LT4250LIN8 PBF LT4250LIN8 TRPBF 4250LI 8-Lead PDIP 40C to 85C LT4250LIS8 PBF LT4250LIS8 TRPBF 4250LI 8-Lead PLASTIC SO 40C to 85C LT4250HCN8 PBF LT4250HCN8 TRPBF 4250H 8-Lead PDIP 0C to 70C LT4250HCS8 PBF LT4250HCS8 TRPBF 4250H 8-Lead PLASTIC SO 0C to 70C LT4250HIN8 PBF LT4250HIN8 TRPBF 4250HI 8-Lead PDIP 40C to 85C LT4250HIS8 PBF LT4250HIS8 TRPBF 4250HI 8-Lead PLASTIC SO 40C to 85C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *The temperature grade is identi ed by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based nish parts. For more information on lead free part marking, go to: