<<As for the zener, the CS453 datasheet shows a 42V breakdown for the driver output transistor. You should use a 30 to 33 volt zener @ 10W (10 W => that from data sheet).>> How about a 5W zener? Digikey's zeners only go up to 5W from what I can tell viewing their web page. No luck at JDR either. Thanks, -Mike