TVS clamp for a 43V rail – 1500W pulse, 69.4V clamp ceiling
The SMCJ43AE3/TR13 is a unidirectional Zener TVS diode from Microchip Technology, rated for 1500W peak pulse power (10/1000 µs waveform) with a reverse standoff voltage of 43V and a minimum breakdown voltage of 47.8V. This part is used for general-purpose transient suppression on DC power rails, signal lines, and I/O ports where the normal operating voltage is 43V or below.
Breakdown and clamping – where the protection window sits
With a 43V reverse standoff, the diode does not conduct at the rail voltage. The breakdown region starts at 47.8V minimum, so a 48V or higher transient triggers avalanche conduction. The clamp voltage of 69.4V maximum at 21.6A peak pulse current sets the upper limit the downstream circuitry must survive. The 1500W peak pulse rating defines the energy the part can absorb in a single 10/1000 µs event before failure.
Active production – no last-time-buy pressure
Microchip lists the SMCJ43AE3/TR13 as Active.
The wide range means the breakdown voltage and clamping characteristics shift with temperature, but the datasheet curves (not reproduced here) let you derate the peak pulse power at elevated temperatures.