What are the challenges in designing power supplies for automotive ECUs?

Automotive power supply challenges include: Wide voltage range (6V during cranking to 42V load dump on 12V systems), transient protection (ISO 7637 pulses up to +/- 200V), reverse polarity protection, ripple and EMC filtering, low dropout operation, multiple voltage rails (5V, 3.3V, 1.2V), sequencing requirements, sleep current minimization (<100uA), high temperature operation, and response to battery disconnect/reconnect. Solutions use input filtering, protection circuits, switched-mode converters with linear post-regulators, and voltage monitoring.