It was 30-45 mins. They had a multi-page booklet with a ton of questions ranging from unit prefixes to differential amplifiers. Though they are mostly all electrical engineering questions that range from basic circuit symbol knowledge, basic knowledge about capacitors , inductors, MOSFETs and BJTs. They also asked questions about various circuits like current mirrors, op amps, and differential amplifiers. The interview was all technical questions and they stressed that the results of the technical interview don't matter as long as you show interest in what they do. I will say this was probably the oddest (not in a bad way) job interview I've ever done.