Obsolete – sourcing window for sustainment
The 1.5KE9.1A is officially marked Obsolete by onsemi. For a BOM line that depends on this part, the only path is to source existing stock or qualify a form-fit-function replacement.
1500W peak pulse – what it means for the rail
Rated for 1500 W peak pulse power at 10/1000 µs waveform. That energy rating determines how much transient overvoltage the diode can shunt before failing. For a 7.78 V standoff rail, the 13.4 V clamp limits the voltage seen by downstream components. The 112 A peak pulse current tells you the diode can handle a high-energy surge, but the actual margin depends on the source impedance and the waveform duration.
DO-201AD axial – through-hole mounting note
The DO-201AD axial package is a through-hole form factor. The leads are bent and soldered into plated through-holes; the body is cylindrical. No exposed thermal pad – heat dissipates through the leads and the PCB copper. The -65°C to 175°C junction temperature range covers military and industrial thermal profiles, but the derating curve for peak pulse power above 25°C must be applied.
Unidirectional – no bidirectional variant in this order code
The 1.5KE9.1A is a single unidirectional channel. The 1.5KE series includes bidirectional versions (suffix CA), but this specific order code is unidirectional. If your application requires bidirectional clamping, the 1.5KE9.1CA is the corresponding part.