600W bidirectional Zener TVS — what you get
The STMicroelectronics P6KE18CARL is a bidirectional Zener transient voltage suppressor from the P6KE, TRANSIL™ series. It's designed for general-purpose surge protection on a 15V rail, with a minimum breakdown voltage of 17.1V and a maximum clamping voltage of 32.5V at the peak pulse current. Rated for 600W peak pulse power (10/1000µs waveform), it can handle a peak pulse current of 123A under the 8/20µs test condition. The device is housed in a DO-204AC (DO-15) axial-lead package for through-hole mounting.
Obsolete — sourcing reality
The P6KE18CARL is listed as obsolete by STMicroelectronics. Sourcing this part now goes through the independent distribution and surplus market.
Key ratings for the BOM decision
The 17.1V minimum breakdown voltage tells you this TVS starts conducting around that threshold, protecting downstream components from overvoltage. The 32.5V maximum clamping voltage is the worst-case voltage the load will see during a surge — make sure your downstream parts can survive that peak. The 600W peak pulse power rating (10/1000µs) defines the energy-handling capability for a typical lightning or inductive surge event. The 123A peak pulse current (8/20µs) is a more aggressive surge condition; this part can handle that current without failing. The 800pF capacitance at 1MHz matters for high-speed signal lines — it can load the line and degrade signal integrity, so check your application's bandwidth requirements.