LM5068 Negative Voltage Hot-Swap Controller General Description The LM5068 hot-swap controller provides intelligent control of power supply connections during the insertion and removal of circuit cards powered by live system backplanes The LM5068 provides both in-rush current control and short-circuit protection functions, and limits power supply transients in the backplane caused by the insertion of additional circuit cards. The LM5068 controls the external N-Channel MOSFET to provide programmable load current limiting and circuit breaker functions using a single external current sense resistor. The LM5068 issues a power good (PWRGD) signal at the conclusion of a successful poweron sequence. Input over-voltage or under-voltage fault conditions will cancel the PWRGD indication. The LM5068-1 and -2 indicate power good as an opendrain active high PWRGD state. The LM5068-3 and -4 indicate power-good as an open-drain active low PWRGD state. The LM5068-1 and -3 latch off after a fault condition is detected while the LM5068-2 and -4 continuously re-try at intervals set by a programmable timer. PRE LIM IN Features ARY • In-rush current limiting for safe board insertion into live backplanes • Fast response to over-current fault conditions with active current limiting • • Wide -10V to -100V input voltage range • Programmable Multi-Function Timer for board insertion de-bounce delay • Fault timer avoids nuisance trips caused by short duration load transients • • Active gate clamping during initial power application • Available with either active HIGH or active LOW power good flag Programmable Under-voltage and Over-voltage shutdown protection with adjustable hysteresis Available in both latched fault and automatic retry versions The LM5068 is available in MSOP-8 package. Samples are available now; volume production is expected in late January 2004. For additional information, contact Don Ashley at [email protected] © 2003 National Semiconductor Corporation