Hot-swap controller monitors board current, voltages and faults -

Hot-swap controller monitors board current, voltages and faults


The LTC4261 is a negative high-voltage hot-swap controller developed by Linear Technology Corp. It features an on-board 10-bit ADC and I2 C compatible interface, allowing sophisticated power monitoring by measuring card voltages and currents as well as recording past and present fault conditions. The LTC4261 complements the company's LTC4260, a positive 48-V hot-swap controller that also features an onboard ADC and I2 C interface.

Information in the ADC’s registers can be queried using the I2 C bus and then used to determine if a card is actually using its allocated power, or operating abnormally. An irregular card can be flagged for service even before it fails. This advanced power monitoring, combined with a wide input voltage range of -12 to -100 V suits the LTC4261 for high-availability telecom/network equipment, such as AdvancedTCA systems. In these systems, careful monitoring of the health and integrity of the power distribution networks is crucial.

The LTC4261 is also designed to turn the supply voltage on and off in a controlled manner. The active current limiting results in a controlled rise in voltage across the card capacitance and protects the backplane supply from voltage drops. The in-rush and over-current limits, as well as the undervoltage/overvoltage thresholds and hysteresis are independently adjustable, giving maximum flexibility and accuracy to proprietary designs. The controller disconnects the load if it remains in current limit beyond the time-out delay and can be configured to latch off or auto-retry following the event.

Specified over the commercial and industrial temperature ranges, the LTC4261 is available from stock in 28-lead SSOP and 24-lead 4- by 5-mm QFN packages. Pricing begins at $5.95 each in 1000-piece quantities. For more information, visit

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