Clamping and breakdown margins
The 1.5KE170CA-T: Breakdown starts at 162 V minimum, and clamping is guaranteed at 234 V maximum at the 6.4 A peak pulse current. That 89 V window between standoff and clamp gives the designer margin to select a downstream DC-DC converter or linear regulator rated for the clamp ceiling. The single bidirectional channel means one device clamps both polarities — no need for two diodes in anti-series. The 175°C TJ ceiling is the absolute limit; derate the peak pulse power above 25°C per the datasheet curve.
Obsolete — sourcing through independent channels
Diodes Incorporated lists the 1.5KE170CA-T as obsolete. No pin-compatible direct replacement from Diodes is documented; a parametric search for a 1500 W bidirectional TVS in DO-201 with a 145 V standoff will identify functionally equivalent alternatives from other brands, but a board respin is not required if the package and footprint match.