LTC4257CDD#PBF

Overview

The LTC4257CDD#PBF is a hot-swap controller designed for high-side N-channel MOSFETs, featuring integrated current limit and voltage monitoring. It supports input voltages from 3V to 60V with a typical quiescent current of 1.5mA. The device includes programmable soft-start via an external capacitor, adjustable current limit thresholds, and fault protection against overvoltage, undervoltage, and short circuits. Operating temperature range spans -40°C to +85°C in an 8-lead DFN package.

Feature Summary

• Integrated high-side N-channel MOSFET driver with precise current limiting
• Programmable soft-start and current limit settings via external components
• Comprehensive fault protection including overvoltage, undervoltage, and thermal shutdown

Applications

• Hot-swap applications in server backplanes
• PCI Express slot power management
• Industrial equipment requiring safe insertion and removal

Procurement Notes

Verify the exact suffix PBF indicates lead-free compliance per RoHS standards. Confirm the DD package marking matches the 8-lead DFN footprint. Ensure the C grade temperature rating aligns with your operational environment requirements before finalizing procurement.

Selection Notes

Select this component when precise current limiting and soft-start control are required for N-channel MOSFETs. Consider the 60V maximum input voltage and the need for external programming components for threshold adjustments. Evaluate the thermal performance within the specified operating temperature range for your specific application constraints.

Part Context

Part of Analog Devices' hot-swap controller family, the LTC4257 complements other models like the LTC4258 and LTC4260 by offering a balance of features and cost for standard hot-swap needs. It serves as a key solution for protecting systems during board insertion in modular designs.

Replacement Considerations

Direct substitutes include the LTC4257IDD#PBF for industrial temperature range or the LTC4257HDC#PBF for higher voltage support. Verify pin compatibility and parameter alignment before substitution.

FAQ

What determines the current limit threshold?

The current limit is set by the voltage on the ILIM pin, which can be adjusted using an external resistor divider connected to the internal reference.

How is soft-start time controlled?

Soft-start time is determined by the value of the capacitor connected to the SS/FLT pin, charging at a constant current provided internally.