600W Zener TVS — automotive-grade bidirectional clamp
The P6SMB24CAT3: It is a single bidirectional channel in the SMB surface-mount package. The 415pF capacitance at 1 MHz is typical for a 600W-class TVS.
onsemi lists the P6SMB24CAT3 as Obsolete. The base product number is P6SMB, and the broader P6SMB series includes many active 600W TVS variants in the same SMB footprint — but a direct pin-compatible replacement with the same 24V bidirectional rating and AEC-Q101 grade would need to be verified against the original BOM's clamping voltage and capacitance requirements.
Package and footprint — DO-214AA SMB
The SMB package is a standard surface-mount outline. The SMB footprint is shared across the entire P6SMB series, so a same-package replacement with a different voltage rating can drop in without a PCB layout change — provided the clamping voltage and peak pulse current still protect the downstream circuitry.