Linear Technology Corporation introduces the LTC4261, a negative high voltage Hot Swap™ controller. It features an onboard 10-bit ADC and I2C compatible interface, allowing sophisticated power monitoring by measuring card voltages and currents as well as recording past and present fault conditions. The LTC4261 complements Linear Technology's LTC4260, a positive 48V Hot Swap controller that also features an onboard ADC and I2C interface.
Information in the ADC's registers can be queried via the I2C 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 -12V to -100V and Hot Swap capabilities, make the LTC4261 ideally suited 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 inrush and overcurrent 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.
The LTC4261 has additional features to interrupt the host when a fault has occurred, notify when output power is good, detect insertion of a board, and turn off the pass transistor if an external supply monitor fails to indicate powergood within a timeout period.
Specified over the commercial and industrial temperature ranges, the LTC4261 is available from stock in 28-lead SSOP and 24-lead 4mm x 5mm QFN packages. Pricing begins at $5.95 each in 1,000-piece quantities.
Summary of Features: LTC3809-1
Allows Safe Insertion into Live Backplane
10-Bit ADC Monitors Current & Voltage
I2C /SMBus Compatible Interface
Wide Operating Voltage Range: -12V to -100V
Independently Adjustable Inrush and Overcurrent Limits
Adjustable UV/OV Thresholds and Hysteresis
Programmable Latchoff or Autoretry after Faults
Alerts Host after Faults
Foldback Current Limit
Available in 28-Lead SSOP & 24- Lead (4mm x 5mm) QFN Packages