What the 600 W rating means for line protection
The P6KE47CA-T: For a sustained overvoltage or a longer-duration surge, the power-handling capability derates; the 9.3 A peak pulse current (at 10/1000 µs) is the current limit at the clamping voltage of 64.8 V.
Bidirectional clamp — one part for both polarities
The breakdown voltage range (44.7 V min) and the reverse standoff voltage (40.2 V) mean the device starts conducting just above the nominal rail and holds the clamp at 64.8 V max. For a 40 V DC bus or a 28 VAC signal line, the standoff voltage sits below the rail with margin, so the diode does not leak during normal operation.
Obsolete — sourcing through independent channels
Diodes Incorporated lists the P6KE47CA-T as obsolete.