The 1.5SMC27CAHM3_A/H: It clamps a 40 A surge to 37.5 V maximum, protecting downstream circuitry from transients on 24 V nominal rails.
Clamping voltage and standoff margin
Breakdown occurs at a minimum of 25.7 V, providing a 2.6 V guard band before the TVS starts shunting current. A downstream DC-DC converter or ECU with a 40 V abs-max input rating has 2.5 V of headroom above the clamp.
DO-214AB (SMC) package and reel storage
Housed in the standard DO-214AB (SMC) surface-mount package, the diode occupies the same footprint as other 1.5 kW TVS devices in this form factor. The cathode band is marked for orientation; the bidirectional variant has no polarity and can be placed in either direction. Supplied on Tape & Reel, the reels should be stored in a dry environment per JEDEC MSL level — the DO-214AB body is not hermetic, and moisture absorbed during storage can cause package cracking during reflow.