The LTC4260 from Linear Technology Corp. is a positive high-voltage hot-swap controller that features an on-chip 8-bit ADC and I2C compatible interface. This allows for sophisticated power monitoring by measuring card voltages and currents as well as recording past and present fault conditions. Information in the ADC's registers can be queried via the I2C bus to determine if a card is actually using its allocated power or if it is operating abnormally. An irregular card can be flagged for service, perhaps even before it fails. The advanced power monitoring and hot swap capabilities, combined with a wide input voltage range of 8.5 V up to 80 V, make the LTC4260 ideally suited for high availability telecom/network equipment, where careful monitoring of the health and integrity of the power distribution network is crucial.
The hot-swap controller is designed to turn the supply voltage on and off in a controlled manner. The active current limiting results in a controlled rise in the voltage across the card capacitance and protects the backplane supply from voltage drops. The LTC4260 disconnects the load if it remains in current limit beyond the adjustable time-out delay and can be configured to latch off or autoretry following the event. In addition, the LTC4260 monitors for under/overvoltage conditions and uses its feedback and power good comparators to determine the output voltage status.
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