Looking for the smallest & most reliable method of dropping 360V down to ~1V for a PMIC feedback pin. Reliability is probably the most important variable here.
In general are we be better off with two 1206 resistors in series OR 1 high voltage rated 2010 resistor? Note - I'm not concerned about safety, just reliability.
The given creepage distance is approximately the same based on footprints. In either case, a failure of a single resistor will ruin the product.
A single high voltage resistor may be better, given a spot of pollution/dust across the large resistor will have a smaller probability of causing a breakdown given the same size spot on one of the smaller resistors since the spot to creepage distance ratio is smaller on the single larger resistor.
- Sealed system, internally generates a high voltage (360V DC).) As such no UL type creepage/clearence requirements needed.
- PMIC generates 360V, ~50W. System has over-current limit, etc.
- Failure of feedback network will not be a safety issue, just a reliability issue.
- Medium cost manufacturing in China, but no board pollution IPC specification.
- The high voltage is not from line voltages. This is a secondary voltage generated from 24V.