3A fixed-output LDO for power-sensitive rails
The LP3966ES-3.3 from Texas Instruments is a single-output, positive fixed 3.3V LDO regulator rated for 3A continuous output. The maximum dropout voltage is 1.2V at the full 3A load.
Dropout voltage at 3A — what it means for the rail budget
The 1.2V maximum dropout at 3A is the number that decides whether this part works in a given power chain.
Package and thermal handling for 3A
The LP3966ES-3.3 comes in a TO-263-6 (D2Pak) surface-mount package with an exposed tab that must be soldered to a copper plane for heat sinking. At 3A output with a 1.2V dropout, the power dissipated is roughly 3.6W — that heat has to go somewhere. The DDPAK footprint on a 2oz copper board with adequate via stitching can keep the junction temperature within the -40°C to 125°C operating range. Without that thermal path, the over-temperature protection will cycle the output.
Active production — no LTB concern for new builds
The LP3966ES-3.3 carries an active lifecycle status. There is no last-time-buy notice, no end-of-life announcement, and no successor part number to track. For a BOM freeze or a new design, this part does not introduce obsolescence risk.
Protection features for fault-tolerant rails
Over-current, over-temperature, and short-circuit protection are all on-chip. If the output is shorted to ground, the current limit engages; if the die temperature exceeds the threshold, the thermal shutdown latches the output off until it cools. These are the same protection set used in automotive-grade LDOs, and they let the part survive a fault without external crowbar or fuse circuitry.