1MHz switching — what it means for the transformer
The 1MHz maximum switching frequency is the headline parameter for this controller.
Full-bridge topology with 100% duty cycle
This controller implements full-bridge topology, which is the standard choice for higher-power isolated converters (typically 500W to several kW) where the primary-side switches see only half the input voltage compared to a half-bridge. The 100% duty cycle capability means the controller can drive the primary switches to full on-time, maximizing power throughput. Combined with current-mode control (implied by the current-limiting fault protection), it offers good line transient rejection and inherent cycle-by-cycle current limiting.
Lifecycle and sourcing reality
The UC3875DWPTR is listed as Active in production status. It is ROHS3 compliant. For BOM planning, this means no immediate obsolescence risk — the part is qualified for new designs and ongoing production.
