What this 1500W bidirectional TVS protects
The 1.5KE75CA-T: It clamps transients on a 64.1 V nominal rail — the reverse standoff voltage — and breaks down at a minimum of 71.3 V to begin conducting, holding the clamp to 103 V maximum at the 14.6 A peak pulse current. Bidirectional means a single device handles both positive and negative surges, which simplifies board layout for AC-coupled signal lines or DC rails where the polarity could reverse during a fault. The 1500 W rating at 10/1000 µs is the standard telecom surge waveform — this part is sized for industrial and general-purpose transient suppression, not for power-line primary protection.
Housed in a DO-201AA (DO-27) axial-lead package, the 1.5KE75CA-T is a through-hole part. The DO-201 footprint is larger than the common DO-41 or SMA packages — the body diameter is roughly 5.3 mm and the lead diameter about 1.3 mm, so the PCB hole and pad must be sized accordingly. The wide junction temperature margin means the peak-pulse derating at elevated ambient is less aggressive than on a 150°C-rated part — at 125°C ambient the derating factor is roughly 60% of the 25°C rating, so the effective pulse power is still ~900 W.
Diodes Incorporated lists the 1.5KE75CA-T as Obsolete. The 1.5KE75 family (base product number 1.5KE75) includes unidirectional and bidirectional variants in the same package, but a direct pin-compatible replacement from Diodes Inc. is not published.