cant find a data sheet, who makes those?
certainly looks impressive for only 125 W, darlingtons are fine as singles, but are hard to parallel devices.
I like the idea of a PNP driver for low V drop out, but is moot for a lab supply I suppose.
I propose at least 2 NPN pass devices, with a PNP driver! mainly for those of us that may use the schematic for designing fixed/ adjustable supplies for 'green' designs.
edit> I would be willing to trade 2 x 2N6259 GE/RCA devices shipped for a PCB
250W 170V 15A typical Beta = 25 at 10A > these are real SOA beasts
I think 1 of these> 4 x 2N3055 at 70-80V
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I could not find the data sheet on line either, it has not been in production for many years. I have Fairchild data book with the FT359 data sheet. The SOA is 10A @ 15V and 1A @ 50V. I have more devices than I will ever need and I’m happy trade/give you want for your personal use.
Design considerations for paralleling power devices must take into account the inherent imbalance in current. The current imbalance also causes thermal imbalance which exacerbates the Vbe differences causing further current imbalance. The design must account for the device that sees the highest power due to the imbalance. The designer must decide if the Darlington device advantages outweigh the disadvantages.
I worked in the engineering lab at Fairchild Semiconductor and talked to a power device test engineer regarding the 2N3055. He said the 2N3055 specifications designed to allow just about any power transistor meet the specifications. I didn’t understand until he told me the new parking lot asphalt was mixed with several tons of transistor rejects that functioned but did not meet specifications. The low performance specifications of the 2N3055 allowed the company to sell all functional rejects as a 2N3055.
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