What the 1.5KE7V5CA is and what it protects
The STMicroelectronics 1.5KE7V5CA is a bidirectional transient voltage suppression (TVS) diode from the 1.5KE, TRANSIL™ series. It is designed to clamp overvoltage transients on power rails, DC buses, and low-frequency signal lines in general-purpose industrial, telecom, and consumer equipment. With a 1500W peak pulse power rating and a single bidirectional channel, it protects against surges such as those defined by IEC 61000-4-5 or similar 10/1000µs and 8/20µs waveforms.
Above that, breakdown occurs at a minimum of 7.13V, and under a surge the clamping voltage is held to 14.5V maximum at the rated peak pulse current of 690A (8/20µs waveform). For a 5V or 6V rail, this part provides a tight clamp margin — the 14.5V ceiling keeps downstream silicon within safe operating area for most 12V-rated components.
Capacitance — a constraint for fast signals
The 4250pF capacitance at 1MHz is high. This part is intended for power or low-speed I/O protection, not high-speed data lines (Ethernet, USB, HDMI) where the capacitive load would distort the signal. On a 12V DC motor-drive bus or a relay coil supply, the capacitance is irrelevant.
Housed in a DO-201AA (DO-27) axial-lead package, it is a through-hole device intended for manual or wave-solder assembly. The DO-201 body is common for 1500W-rated TVS diodes and offers good thermal mass for pulse dissipation. The axial leads suit point-to-point wiring, terminal blocks, or PCB mounting with 0.4-inch lead spacing.
Lifecycle reality — obsolete, but available
The 1.5KE7V5CA is listed as obsolete. STMicroelectronics no longer manufactures this exact order code in volume. For new designs, a functionally equivalent TVS diode from the same 1.5KE family or a modern SMD alternative should be evaluated.