LT4250H Datasheet | Linear Technology

LT4250L/LT4250H Negative 48V Hot Swap Controller Features Allows Safe Board Insertion and Removal from a Live - 48V Backplane s Circuit Breaker Immunity to Voltage Steps and Current Spikes s Programmable Inrush and .. Short-Circuit Current Limits s Pin patible with LT1640L/LT1640H s Operates from - 20V to - 80V s Programmable Overvoltage Protection s Programmable Undervoltage Lockout s Power Good Control Output s Bell-Core patible ON/OFF Threshold s DESCRIPTIO U APPLICATIO S s s s The LT®4250L/LT4250H are 8-pin, negative 48V Hot Swap TM controllers that allow a board to be safely inserted and removed from a live backplane. Inrush current is limited to a programmable value by controlling the gate voltage of an external N-channel pass transistor. The pass transistor is turned off if the input voltage is less than the programmable undervoltage threshold or greater than the overvoltage threshold. A programmable current limit protects the system against shorts. After a 500µs timeout the current limit activates the electronic circuit breaker. The PWRGD (LT4250L) or PWRGD (LT4250H) signal can 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. The LT4250L/LT4250H are available in 8-pin PDIP and SO packages. , LTC and LT are registered trademarks of Linear Technology Corporation. Hot Swap is a trademark of Linear Technology Corporation. Central Office Switching - 48V Distributed Power Systems Negative Power Supply Control TYPICAL APPLICATIO - 48V RTN (SHORT PIN) - 48V RTN R4† 549k 1% 3 R5† 6.49k 1% R6† 10k 1% UV 8 VDD 1 UV = 38.5V UV RELEASE AT 43V OV = 71V LT4250L 2 OV VEE 4 SENSE 5 GATE 6 R3† 1k, 5% PWRGD DRAIN 7 VEE AND DRAIN 20V/DIV - - 48V INPUT 1 0.1µF 10V R1† 0.02Ω 5% C1† 470n F 25V R2 10Ω 5% C2† 15n F 100V 2 ON/OFF 1 9 VOUT+ VIN+ 8 + SENSE 7 TRIM - 6 SENSE 4 5 VOUT- VIN- LUCENT JW050A1-E ID (Q1) 5A/DIV Q1...