What this Zener TVS protects against
The SMAJ64AE3/TR13 is a unidirectional Zener TVS diode in the DO-214AC (SMA) surface-mount package, rated for 500W peak pulse power on the 10/1000µs waveform. It clamps transients on a 64V rail, with a minimum breakdown of 71.1V and a maximum clamping voltage of 103V at 4.9A peak pulse current.
Sizing the protection for a 64V rail
The 64V reverse standoff voltage means this TVS will not conduct on a nominal 48V or 60V bus, but will start avalanching at 71.1V minimum. The 103V clamping maximum sets the upper bound the downstream circuitry must survive — for a 64V rail, that typically means 100V-rated capacitors and 100V MOSFETs. The 4.9A peak pulse current at the 10/1000µs waveform defines the surge the device can absorb; for a given transient source impedance, the peak current the TVS sees equals (V_transient - V_clamp) / Z_source. If the expected surge exceeds 4.9A, step up to a higher power rating in the same SMAJ family or parallel two devices.
Microchip lists the SMAJ64AE3/TR13 as Active. The part ships on Tape & Reel (TR) in the DO-214AC (SMA) package.
Package and rework in the field
DO-214AC (SMA) is a two-pad footprint with the cathode marked by a band on the body. The part is small enough to swap with a standard hot-air station — no lab bench required.