HV300

HV300 Hotswap, Inrush Current Limiter Controllers (Negative Supply Rail) Features ► PWRGD = Active HIGH ► -10V to -90V input voltage range ► Few external components ► 0.33mA typical standby supply current ► Programmable over/under voltage limits with hysteresis ► Programmable current limit ► Active control during all phases of start-up ► Programmable timing ► 8-Lead SOIC package Applications ► Central office switching ► Servers ► POTS line cards ► ISDN line cards ► xDSL line cards ► PBX Systems ► Powered Ethernet for VoIP ► Distributed power systems ► Negative power supply control ► Antenna and fixed wireless systems General Description The Supertex HV300, Hotswap Controller, Negative Supply controls the power supply connection during insertion of cards or modules into live backplanes. It may be used in traditional ‘negative 48V’ powered systems or for higher voltage busses up to negative 90V. Operation during the initial power up prevents turn-on glitches, and after complete charging of load capacitors (typically found in filters at the input of DC-DC converters) the HV300 issues a power good signal. This signal is typically used to enable the DC-DC converter. Once a PWRGD signal has been established, the device sleeps in a low power state, important for large systems with many individual hotswap cards or modules. An external power MOSFET is required as the pass element, plus a ramp capacitor, and resistors to establish current limiting and over and under voltage lockouts. T...