What the obsolete status means for your BOM
The 1.5SMC75AT3G: Existing builds using this TVS can still be sourced through independent channels, but quantities are lot-specific and availability must be confirmed at RFQ. No authorized-stock channel holds this part as a live inventory line.
What 64.1V standoff and 103V clamping mean for the protection envelope
The reverse standoff of 64.1V is the working voltage the TVS presents to the line when no transients are present — the protected rail should sit below this value in normal operation. The 1500W peak pulse rating defines the surge energy the part can absorb without degradation — this is a 1.5kW-class unidirectional TVS in the SMC footprint, suited for secondary protection on lower-current rails where a 1.5kW clamp handles the line. It is not a power-line protection device — the evidence explicitly marks Power Line Protection as No.
Device type and series positioning
The 1.5SMC75AT3G is a unidirectional Zener-type TVS diode — it clamps in one polarity only, unlike a bidirectional TVS which protects both rails. The series name 1.5SMC indicates the 1.5kW peak pulse power class in the SMC package; the suffix 75A designates the nominal standoff voltage (75V nominal, with the A suffix confirming the voltage binning). The T3G suffix identifies the Pb-Free / RoHS-compliant part variant.