Hot swap controller with I²C telemetry — what it does on the board
What sets this controller apart from a basic hot swap clamp is the I²C interface. You get real-time readback of current, voltage, and fault status over the bus, plus programmable settings for current limit, fault timeout, auto-retry, and latched fault behaviour. Overvoltage and undervoltage lockout thresholds are also configurable through the I²C port or external resistor dividers.
I²C interface — what you can read and set
The I²C bus on the LTC4215CUFD#PBF gives you access to an ADC that measures the voltage across the sense resistor and the supply rail. You can read the current draw of your board, the input voltage, and the status of the fault latch. On the control side, you set the current limit threshold, the overvoltage and undervoltage trip points, and the behaviour after a fault — whether it latches off, retries automatically, or times out and tries again. This telemetry is useful for system health monitoring — a BMC or service processor can poll the LTC4215 to detect a board drawing excessive current before the breaker trips, or log the power-on surge profile during qualification. The I²C address is set via pin strapping, so multiple controllers can share the same bus in a multi-slot chassis.
Package and layout — 24-QFN with exposed pad
The part comes in a 24-lead QFN measuring 4x5 mm with an exposed pad on the bottom. That pad must be soldered to the PCB ground plane for thermal relief — the controller itself dissipates little power (the 3 mA supply current is mostly the I²C interface and internal bias), but the pad also provides a low-inductance return path for the gate drive and sense circuitry. Surface-mount only, no through-hole option. The shipping medium is Tube. The tape-and-reel variant is LTC4215IUFD#TRPBF — same die, same footprint, different packaging.
Lifecycle and sourcing — active, no LTB risk
The LTC4215CUFD#PBF has Active product status and is ROHS3 compliant. No last-time-buy or end-of-life notice exists for this order code.