Transient suppression for a 24 V rail
The P6KE27CA-B is a 600 W bidirectional Zener TVS diode from Diodes Incorporated, housed in a DO-204AC (DO-15) axial-lead package. The 23.1 V standoff rating means the diode will not conduct appreciably below that level, so it sits across a 24 V supply rail without loading it during normal operation. When a transient exceeds the minimum breakdown voltage of 25.7 V, the device avalanches and clamps the surge to 37.5 V, protecting downstream silicon rated for 40 V or higher.
Clamping voltage and pulse current
For a 24 V rail feeding a DC-DC converter with a 40 V abs-max input, this clamp provides a 2.5 V safety margin before the converter's internal FET sees avalanche stress. At the maximum operating temperature of 175 °C (TJ), the derated power is approximately 25% of the 25 °C rating, or about 150 W — still sufficient for most industrial transient events on a 24 V rail, but worth checking against the expected surge energy in the application. The single bidirectional channel replaces two unidirectional diodes in anti-series, saving board space and reducing part count.
Package and board integration
The DO-15 axial package is a through-hole form factor with a body diameter of 3.6 mm and a length of 6.4 mm (typical). The leads are tin-plated copper, rated for wave-solder assembly. The axial lead bend radius should be at least 2 mm to avoid stress cracking the glass passivation layer on the die. The 175 °C upper limit is typical for glass-passivated TVS diodes and allows the device to survive brief high-temperature excursions during wave solder or rework without derating the pulse power capability.
The base product number P6KE27 covers both unidirectional and bidirectional variants in the same DO-15 package. The '-B' suffix indicates the bulk-pack option, typically supplied in tubes or loose in a bag, not tape-and-reel. For reeled quantities, the '-T' or '-TR' suffix variant is the equivalent.